This is Gentoo's testing wiki. It is a non-operational environment and its textual content is outdated.
Please visit our production wiki at https://wiki.gentoo.org
Gentoo Linux Handbook: Installing Gentoo
Do not try to follow instructions directly from the Handbook:Parts namespace (or any of its sub-pages). Handbook:Parts is a meta handbook used for transcluding text. Use the architecture-specific Handbooks found in the Handbook list.
Introduction
Welcome
First of all, welcome to Gentoo! You are about to enter the world of choices and performance. Gentoo is all about choices. When installing Gentoo, this is made clear several times - users can choose how much they want to compile themselves, how to install Gentoo, what system logger to use, etc.
Gentoo is a fast, modern meta-distribution with a clean and flexible design. It is built on an ecosystem of free software and does not hide what is beneath the hood from its users. Portage, the package maintenance system which Gentoo uses, is written in Python, meaning the user can easily view and modify the source code. Gentoo's packaging system uses source code (although support for pre-compiled packages is included too) and configuring Gentoo happens through regular text files. In other words, openness everywhere.
It is very important that everyone understands that choices are what makes Gentoo run. We try not to force users into anything they do not like. If anyone believes otherwise, please bug report it.
How the installation is structured
The Gentoo Installation can be seen as a 10-step procedure, corresponding to the next set of chapters. Each step results in a certain state:
| Step | Result |
|---|---|
| 1 | The user is in a working environment ready to install Gentoo. |
| 2 | The Internet connection is ready to install Gentoo. |
| 3 | The hard disks are initialized to host the Gentoo installation. |
| 4 | The installation environment is prepared and the user is ready to chroot into the new environment. |
| 5 | Core packages, which are the same on all Gentoo installations, are installed. |
| 6 | The Linux kernel is installed. |
| 7 | The user will have configured most of the Gentoo system configuration files. |
| 8 | The necessary system tools are installed. |
| 9 | The proper boot loader has been installed and configured. |
| 10 | The freshly installed Gentoo Linux environment is ready to be explored. |
Whenever a certain choice is presented the handbook will try to explain the pros and cons of each choice. Although the text then continues with a default choice (identified by "Default: " in the title), the other possibilities will be documented as well (marked by "Alternative: " in the title). Do not think that the default is what Gentoo recommends. It is however what Gentoo believes most users will use.
Sometimes an optional step can be followed. Such steps are marked as "Optional: " and are therefore not needed to install Gentoo. However, some optional steps are dependent on a previously made decision. The instructions will inform the reader when this happens, both when the decision is made, and right before the optional step is described.
Installation options for Gentoo
Gentoo can be installed in many different ways. It can be downloaded and installed from official Gentoo installation media such as our CDs and DVDs. The installation media can be installed on a USB stick or accessed via a netbooted environment. Alternatively, Gentoo can be installed from non-official media such as an already installed distribution or a non-Gentoo bootable disk (such as Knoppix).
This document covers the installation using official Gentoo Installation media or, in certain cases, netbooting.
For help on the other installation approaches, including using non-Gentoo CDs, please read our Alternative installation guide.
We also provide a Gentoo installation tips and tricks document that might be useful to read as well.
Troubles
If a problem is found in the installation (or in the installation documentation), please visit our bug tracking system and check if the bug is known. If not, please create a bug report for it so we can take care of it. Do not be afraid of the developers who are assigned to the bugs - they (generally) don't eat people.
Note though that, although this document is architecture-specific, it might contain references to other architectures as well. This is due to the fact that large parts of the Gentoo Handbook use installation source text that is shared for all architectures (to avoid duplication of efforts and starvation of development resources). We will try to keep this to a minimum to avoid confusion.
If there is some uncertainty whether or not the problem is a user-problem (some error made despite having read the documentation carefully) or a software-problem (some error we made despite having tested the installation/documentation carefully) everybody is welcome to join the #gentoo channel on irc.freenode.net. Of course, everyone is welcome otherwise too as our chat channel covers the broad Gentoo spectrum.
Speaking of which, if there are any additional questions regarding Gentoo, check out the Frequently Asked Questions article. There are also FAQs on the Gentoo Forums.
Hardware requirements
Before we start, we first list what hardware requirements are needed to successfully install Gentoo on a box.
| Minimal CD | LiveDVD | |
|---|---|---|
| CPU | ||
| Memory | ||
| Disk space | ||
| Swap space |
Gentoo Linux installation media
Minimal installation CD
As of August 23, 2018 the official Minimal CDs are capable of booting in UEFI mode. Previous versions boot in BIOS (MBR) mode only. Readers looking to make their system UEFI bootable must download the latest ISO.
The Gentoo minimal installation CD is a bootable image which contains a self-sustained Gentoo environment. It allows the user to boot Linux from the CD or other installation media. During the boot process the hardware is detected and the appropriate drivers are loaded. The image is maintained by Gentoo developers and allows anyone to install Gentoo if an active Internet connection is available.
The Minimal Installation CD is called install--minimal-<release>.iso.
The occasional Gentoo LiveDVD
Occasionally, a special DVD is crafted by the Gentoo Ten project which can be used to install Gentoo. The instructions further down this chapter target the Minimal Installation CD so might be a bit different. However, the LiveDVD (or any other bootable Linux environment) supports getting a root prompt by just invoking sudo su - or sudo -i in a terminal.
What are stages then?
A stage3 tarball is an archive containing a minimal Gentoo environment, suitable to continue the Gentoo installation using the instructions in this manual. Previously, the Gentoo Handbook described the installation using one of three stage tarballs. While Gentoo still offers stage1 and stage2 tarballs, the official installation method uses the stage3 tarball. If you are interested in performing a Gentoo installation using a stage1 or stage2 tarball, please read the Gentoo FAQ on How do I install Gentoo using a stage1 or stage2 tarball?
Stage3 tarballs can be downloaded from releases//autobuilds/ on any of the official Gentoo mirrors. Stage files update frequently and are not included on the installation images.
Downloading
Obtain the media
The default installation media that Gentoo Linux uses are the minimal installation CDs, which host a bootable, very small Gentoo Linux environment. This environment contains all the right tools to install Gentoo. The CD images themselves can be downloaded from the downloads page (recommended) or by manually browsing to the ISO location on one of the many available mirrors.
If downloading from a mirror, the minimal installation CDs can be found as follows:
- Go to the releases/ directory.
- Select the directory for the relevant target architecture (such as /).
- Select the autobuilds/ directory.
- For amd64 and x86 architectures select either the current-install-amd64-minimal/ or current-install-x86-minimal/ directory (respectively). For all other architectures navigate to the current-iso/ directory.
Some target architectures such as arm, mips, and s390 will not have minimal install CDs. At this time the Gentoo Release Engineering project does not support building .iso files for these targets.
Inside this location, the installation media file is the file with the .iso suffix. For instance, take a look at the following listing:
[DIR] hardened/ 05-Dec-2014 01:42 - [ ] install--minimal-20141204.iso 04-Dec-2014 21:04 208M [ ] install--minimal-20141204.iso.CONTENTS 04-Dec-2014 21:04 3.0K [ ] install--minimal-20141204.iso.DIGESTS 04-Dec-2014 21:04 740 [TXT] install--minimal-20141204.iso.DIGESTS.asc 05-Dec-2014 01:42 1.6K [ ] stage3--20141204.tar.bz2 04-Dec-2014 21:04 198M [ ] stage3--20141204.tar.bz2.CONTENTS 04-Dec-2014 21:04 4.6M [ ] stage3--20141204.tar.bz2.DIGESTS 04-Dec-2014 21:04 720 [TXT] stage3--20141204.tar.bz2.DIGESTS.asc 05-Dec-2014 01:42 1.5K
In the above example, the install--minimal-20141204.iso file is the minimal installation CD itself. But as can be seen, other related files exist as well:
- A .CONTENTS file which is a text file listing all files available on the installation media. This file can be useful to verify if particular firmware or drivers are available on the installation media before downloading it.
- A .DIGESTS file which contains the hash of the ISO file itself, in various hashing formats/algorithms. This file can be used to verify if the downloaded ISO file is corrupt or not.
- A .DIGESTS.asc file which not only contains the hash of the ISO file (like the .DIGESTS file), but also a cryptographic signature of that file. This can be used to both verify if the downloaded ISO file is corrupt or not, as well as verify that the download is indeed provided by the Gentoo Release Engineering team and has not been tampered with.
Ignore the other files available at this location for now - those will come back when the installation has proceeded further. Download the .iso file and, if verification of the download is wanted, download the .DIGESTS.asc file for the .iso file as well. The .CONTENTS file does not need to be downloaded as the installation instructions will not refer to this file anymore, and the .DIGESTS file should contain the same information as the .DIGESTS.asc file, except that the latter also contains a signature on top of it.
Verifying the downloaded files
This is an optional step and not necessary to install Gentoo Linux. However, it is recommended as it ensures that the downloaded file is not corrupt and has indeed been provided by the Gentoo Infrastructure team.
Through the .DIGESTS and .DIGESTS.asc files, the validity of the ISO file can be confirmed using the right set of tools. This verification is usually done in two steps:
- First, the cryptographic signature is validated to make sure that the installation file is provided by the Gentoo Release Engineering team
- If the cryptographic signature validates, then the checksum is verified to make sure that the downloaded file itself is not corrupted
Microsoft Windows based verification
On a Microsoft Windows system, chances are low that the right set of tools to verify checksums and cryptographic signatures are in place.
To first verify the cryptographic signature, tools such as GPG4Win can be used. After installation, the public keys of the Gentoo Release Engineering team need to be imported. The list of keys is available on the signatures page. Once imported, the user can then verify the signature of the .DIGESTS.asc file.
This does not verify that the .DIGESTS file is correct, only that the .DIGESTS.asc file is. That also implies that the checksum should be verified against the values in the .DIGESTS.asc file, which is why the instructions above only refer to downloading the .DIGESTS.asc file.
The checksum itself can be verified using the Hashcalc application, although many others exist as well. Most of the time, these tools will show the user the calculated checksum, and the user is requested to verify this checksum with the value that is inside the .DIGESTS.asc file.
Linux based verification
On a Linux system, the most common method for verifying the cryptographic signature is to use the app-crypt/gnupg software. With this package installed, the following commands can be used to verify the cryptographic signature of the .DIGESTS.asc file.
First, download the right set of keys as made available on the signatures page:
user $gpg --keyserver hkps://hkps.pool.sks-keyservers.net --recv-keys 0xBB572E0E2D182910gpg: requesting key 0xBB572E0E2D182910 from hkp server pool.sks-keyservers.net gpg: key 0xBB572E0E2D182910: "Gentoo Linux Release Engineering (Automated Weekly Release Key) <releng@gentoo.org>" 1 new signature gpg: 3 marginal(s) needed, 1 complete(s) needed, classic trust model gpg: depth: 0 valid: 3 signed: 20 trust: 0-, 0q, 0n, 0m, 0f, 3u gpg: depth: 1 valid: 20 signed: 12 trust: 9-, 0q, 0n, 9m, 2f, 0u gpg: next trustdb check due at 2018-09-15 gpg: Total number processed: 1 gpg: new signatures: 1
Next verify the cryptographic signature of the .DIGESTS.asc file:
user $gpg --verify install--minimal-20141204.iso.DIGESTS.ascgpg: Signature made Fri 05 Dec 2014 02:42:44 AM CET gpg: using RSA key 0xBB572E0E2D182910 gpg: Good signature from "Gentoo Linux Release Engineering (Automated Weekly Release Key) <releng@gentoo.org>" [unknown] gpg: WARNING: This key is not certified with a trusted signature! gpg: There is no indication that the signature belongs to the owner. Primary key fingerprint: 13EB BDBE DE7A 1277 5DFD B1BA BB57 2E0E 2D18 2910
To be absolutely certain that everything is valid, verify the fingerprint shown with the fingerprint on the Gentoo signatures page.
With the cryptographic signature validated, next verify the checksum to make sure the downloaded ISO file is not corrupted. The .DIGESTS.asc file contains multiple hashing algorithms, so one of the methods to validate the right one is to first look at the checksum registered in the .DIGESTS.asc file. For instance, to get the SHA512 checksum:
user $grep -A 1 -i sha512 install--minimal-20141204.iso.DIGESTS.asc# SHA512 HASH 364d32c4f8420605f8a9fa3a0fc55864d5b0d1af11aa62b7a4d4699a427e5144b2d918225dfb7c5dec8d3f0fe2cddb7cc306da6f0cef4f01abec33eec74f3024 install--minimal-20141204.iso -- # SHA512 HASH 0719a8954dc7432750de2e3076c8b843a2c79f5e60defe43fcca8c32ab26681dfb9898b102e211174a895ff4c8c41ddd9e9a00ad6434d36c68d74bd02f19b57f install--minimal-20141204.iso.CONTENTS
In the above output, two SHA512 checksums are shown - one for the install--minimal-20141204.iso file and one for its accompanying .CONTENTS file. Only the first checksum is of interest, as it needs to be compared with the calculated SHA512 checksum which can be generated as follows:
user $sha512sum install--minimal-20141204.iso364d32c4f8420605f8a9fa3a0fc55864d5b0d1af11aa62b7a4d4699a427e5144b2d918225dfb7c5dec8d3f0fe2cddb7cc306da6f0cef4f01abec33eec74f3024 install--minimal-20141204.iso
As both checksums match, the file is not corrupted and the installation can continue.
Burning a disk
Of course, with just an ISO file downloaded, the Gentoo Linux installation cannot be started. The ISO file needs to be burned on a CD to boot from, and in such a way that its content is burned on the CD, not just the file itself. Below a few common methods are described - a more elaborate set of instructions can be found in Our FAQ on burning an ISO file.
Burning with Microsoft Windows
On Microsoft Windows, a number of tools exist that support burning ISOs on CDs.
- With EasyCD Creator, select File, Record CD from CD image. Then change the Files of type to ISO image file. Then locate the ISO file and click Open. After clicking on Start recording the ISO image will be burned correctly onto the CD-R.
- With Nero Burning ROM, cancel the wizard which automatically pops up and select Burn Image from the File menu. Select the image to burn and click Open. Now hit the Burn button and watch the brand new CD being burnt.
Burning with Linux
On Linux, the ISO file can be burned on a CD using the cdrecord command, part of the app-cdr/cdrtools package.
For instance, to burn the ISO file on the CD in the /dev/sr0 device (this is the first CD device on the system - substitute with the right device file if necessary):
user $cdrecord dev=/dev/sr0 install--minimal-20141204.isoUsers that prefer a graphical user interface can use K3B, part of the kde-apps/k3b package. In K3B, go to Tools and use Burn CD Image. Then follow the instructions provided by K3B.
Booting
This is a placeholder for architecture-specific booting information
Extra hardware configuration
When the Installation medium boots, it tries to detect all the hardware devices and loads the appropriate kernel modules to support the hardware. In the vast majority of cases, it does a very good job. However, in some cases it may not auto-load the kernel modules needed by the system. If the PCI auto-detection missed some of the system's hardware, the appropriate kernel modules have to be loaded manually.
In the next example the 8139too module (which supports certain kinds of network interfaces) is loaded:
root #modprobe 8139tooOptional: User accounts
If other people need access to the installation environment, or there is need to run commands as a non-root user on the installation medium (such as to chat using irssi without root privileges for security reasons), then an additional user account needs to be created and the root password set to a strong password.
To change the root password, use the passwd utility:
root #passwdNew password: (Enter the new password) Re-enter password: (Re-enter the password)
To create a user account, first enter their credentials, followed by the account's password. The useradd and passwd commands are used for these tasks.
In the next example, a user called john is created:
root #useradd -m -G users john
root #passwd johnNew password: (Enter john's password) Re-enter password: (Re-enter john's password)
To switch from the (current) root user to the newly created user account, use the su command:
root #su - johnOptional: Viewing documentation while installing
TTYs
To view the Gentoo handbook during the installation, first create a user account as described above. Then press Alt+F2 to go to a new terminal.
During the installation, the links command can be used to browse the Gentoo handbook - of course only from the moment that the Internet connection is working.
user $links https://wiki.gentoo.org/wiki/Handbook:PartsTo go back to the original terminal, press Alt+F1.
GNU Screen
The GNU Screen utility is installed by default on official Gentoo installation media. It may be more efficient for the seasoned Linux enthusiast to use screen to view installation instructions via split panes rather than the multiple TTY method mentioned above.
Optional: Starting the SSH daemon
To allow other users to access the system during the installation (perhaps to support during an installation, or even do it remotely), a user account needs to be created (as was documented earlier on) and the SSH daemon needs to be started.
To fire up the SSH daemon on an OpenRC init, execute the following command:
root #rc-service sshd startIf users log on to the system, they will see a message that the host key for this system needs to be confirmed (through what is called a fingerprint). This behavior is typical and can be expected for initial connections to an SSH server. However, later when the system is set up and someone logs on to the newly created system, the SSH client will warn that the host key has been changed. This is because the user now logs on to - for SSH - a different server (namely the freshly installed Gentoo system rather than the live environment that the installation is currently using). Follow the instructions given on the screen then to replace the host key on the client system.
To be able to use sshd, the network needs to function properly. Continue with the chapter on Configuring the network.
Automatic network detection
Maybe it just works?
If the system is plugged into an Ethernet network with a DHCP server, it is very likely that the networking configuration has already been set up automatically. If so, then the many included network-aware commands on the installation CD such as ssh, scp, ping, irssi, wget, and links, among others, will work immediately.
Determine interface names
ifconfig command
If networking has been configured, the ifconfig command should list one or more network interfaces (besides lo). In the example below eth0 shows up:
root #ifconfigeth0 Link encap:Ethernet HWaddr 00:50:BA:8F:61:7A
inet addr:192.168.0.2 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::50:ba8f:617a/10 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1498792 errors:0 dropped:0 overruns:0 frame:0
TX packets:1284980 errors:0 dropped:0 overruns:0 carrier:0
collisions:1984 txqueuelen:100
RX bytes:485691215 (463.1 Mb) TX bytes:123951388 (118.2 Mb)
Interrupt:11 Base address:0xe800
As a result of the shift towards predictable network interface names, the interface name on the system can be quite different from the old eth0 naming convention. Recent installation media might show regular network interfaces names like eno0, ens1, or enp5s0. Look for the interface in the ifconfig output that has an IP address related to the local network.
If no interfaces are displayed when the standard ifconfig command is used, try using the same command with the
-a option. This option forces the utility to show all network interfaces detected by the system whether they be in an up or down state. If ifconfig -a produces no results then the hardware is faulty or the driver for the interface has not been loaded into the kernel. Both situations reach beyond the scope of this Handbook. Contact #gentoo for support.ip command
As an alternative to ifconfig, the ip command can be used to determine interface names. The following example shows the output of ip addr (of another system so the information shown is different from the previous example):
root #ip addr2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
link/ether e8:40:f2:ac:25:7a brd ff:ff:ff:ff:ff:ff
inet 10.0.20.77/22 brd 10.0.23.255 scope global eno1
valid_lft forever preferred_lft forever
inet6 fe80::ea40:f2ff:feac:257a/64 scope link
valid_lft forever preferred_lft forever
The output above may be a bit more complicated to read than alternative. The interface name in the above example directly follows the number; it is eno1.
In the remainder of this document, the handbook will assume that the operating network interface is called eth0.
Optional: Configure any proxies
If the Internet is accessed through a proxy, then it is necessary to set up proxy information during the installation. It is very easy to define a proxy: just define a variable which contains the proxy server information.
In most cases, it is sufficient to define the variables using the server hostname. As an example, we assume the proxy is called proxy.gentoo.org and the port is 8080.
To set up an HTTP proxy (for HTTP and HTTPS traffic):
root #export http_proxy="http://proxy.gentoo.org:8080"To set up an FTP proxy:
root #export ftp_proxy="ftp://proxy.gentoo.org:8080"To set up an RSYNC proxy:
root #export RSYNC_PROXY="proxy.gentoo.org:8080"If the proxy requires a username and password, use the following syntax for the variable:
http://username:password@proxy.gentoo.org:8080
Testing the network
Try pinging your ISP's DNS server (found in /etc/resolv.conf) and a web site of choice. This ensures that the network is functioning properly and that the network packets are reaching the net, DNS name resolution is working correctly, etc.
root #ping -c 3 www.gentoo.orgIf this all works, then the remainder of this chapter can be skipped to jump right to the next step of the installation instructions (Preparing the disks).
Automatic network configuration
If the network doesn't work immediately, some installation media allow the user to use net-setup (for regular or wireless networks), pppoe-setup (for ADSL users) or pptp (for PPTP users).
If the installation medium does not contain any of these tools, continue with the Manual network configuration.
- Regular Ethernet users should continue with Default: Using net-setup
- ADSL users should continue with Alternative: Using PPP
- PPTP users should continue with Alternative: Using PPTP
Default: Using net-setup
The simplest way to set up networking if it didn't get configured automatically is to run the net-setup script:
root #net-setup eth0net-setup will ask some questions about the network environment. When all is done, the network connection should work. Test the network connection as stated before. If the tests are positive, congratulations! Skip the rest of this section and continue with Preparing the disks.
If the network still doesn't work, continue with Manual network configuration.
Alternative: Using PPP
Assuming PPPoE is needed to connect to the Internet, the installation CD (any version) has made things easier by including ppp. Use the provided pppoe-setup script to configure the connection. During the setup the Ethernet device that is connected to your ADSL modem, the username and password, the IPs of the DNS servers and if a basic firewall is needed or not will be asked.
root #pppoe-setup
root #pppoe-startIf something goes wrong, double-check that the username and password are correct by looking at etc/ppp/pap-secrets or /etc/ppp/chap-secrets and make sure to use the right Ethernet device. If the Ethernet device does not exist, the appropriate network modules need to be loaded. In that case continue with Manual network configuration as it will explain how to load the appropriate network modules there.
If everything worked, continue with Preparing the disks.
Alternative: Using PPTP
If PPTP support is needed, use pptpclient which is provided by the installation CDs. But first make sure that the configuration is correct. Edit /etc/ppp/pap-secrets or /etc/ppp/chap-secrets so it contains the correct username/password combination:
root #nano -w /etc/ppp/chap-secretsThen adjust /etc/ppp/options.pptp if necessary:
root #nano -w /etc/ppp/options.pptpWhen all that is done, run pptp (along with the options that couldn't be set in options.pptp) to connect the server:
root #pptp <server ip>Now continue with Preparing the disks.
Manual network configuration
Loading the appropriate network modules
When the Installation CD boots, it tries to detect all the hardware devices and loads the appropriate kernel modules (drivers) to support the hardware. In the vast majority of cases, it does a very good job. However, in some cases, it may not auto-load the kernel modules needed.
If net-setup or pppoe-setup failed, then it is possible that the network card wasn't found immediately. This means users may have to load the appropriate kernel modules manually.
To find out what kernel modules are provided for networking, use the ls command:
root #ls /lib/modules/`uname -r`/kernel/drivers/netIf a driver is found for the network device, use modprobe to load the kernel module. For instance, to load the pcnet32 module:
root #modprobe pcnet32To check if the network card is now detected, use ifconfig. A detected network card would result in something like this (again, eth0 here is just an example):
root #ifconfig eth0eth0 Link encap:Ethernet HWaddr FE:FD:00:00:00:00
BROADCAST NOARP MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
If however the following error is shown, the network card is not detected:
root #ifconfig eth0eth0: error fetching interface information: Device not found
The available network interface names on the system can be listed through the /sys file system:
root #ls /sys/class/netdummy0 eth0 lo sit0 tap0 wlan0
In the above example, 6 interfaces are found. The eth0 one is most likely the (wired) Ethernet adapter whereas wlan0 is the wireless one.
Assuming that the network card is now detected, retry net-setup or pppoe-setup again (which should work now), but for the hardcore people we explain how to configure the network manually as well.
Select one of the following sections based on your network setup:
- Using DHCP for automatic IP retrieval
- Preparing for wireless access if a wireless network is used
- Understanding network terminology explains the basics about networking
- Using ifconfig and route explains how to set up networking manually
Using DHCP
DHCP (Dynamic Host Configuration Protocol) makes it possible to automatically receive networking information (IP address, netmask, broadcast address, gateway, nameservers etc.). This only works if a DHCP server is in the network (or if the ISP provider provides a DHCP service). To have a network interface receive this information automatically, use dhcpcd:
root #dhcpcd eth0Some network administrators require that the hostname and domainname provided by the DHCP server is used by the system. In that case, use:
root #dhcpcd -HD eth0If this works (try pinging some Internet server, like Google's 8.8.8.8 or Cloudflare's 1.1.1.1), then everything is set and ready to continue. Skip the rest of this section and continue with Preparing the disks.
Preparing for wireless access
Support for the iw command might be architecture-specific. If the command is not available see if the net-wireless/iw package is available for the current architecture. The iw command will be unavailable unless the net-wireless/iw package has been installed.
When using a wireless (802.11) card, the wireless settings need to be configured before going any further. To see the current wireless settings on the card, one can use iw. Running iw might show something like:
root #iw dev wlp9s0 infoInterface wlp9s0 ifindex 3 wdev 0x1 addr 00:00:00:00:00:00 type managed wiphy 0 channel 11 (2462 MHz), width: 20 MHz (no HT), center1: 2462 MHz txpower 30.00 dBm
To check for a current connection:
root #iw dev wlp9s0 linkNot connected.
or
root #iw dev wlp9s0 linkConnected to 00:00:00:00:00:00 (on wlp9s0) SSID: GentooNode freq: 2462 RX: 3279 bytes (25 packets) TX: 1049 bytes (7 packets) signal: -23 dBm tx bitrate: 1.0 MBit/s
Some wireless cards may have a device name of wlan0 or ra0 instead of wlp9s0. Run ip link to determine the correct device name.
For most users, there are only two settings needed to connect, the ESSID (aka wireless network name) and, optionally, the WEP key.
- First, ensure the interface is active:
root #ip link set dev wlp9s0 up
- To connect to an open network with the name GentooNode:
root #iw dev wlp9s0 connect -w GentooNode
- To connect with a hex WEP key, prefix the key with
d::
root #iw dev wlp9s0 connect -w GentooNode key 0:d:1234123412341234abcd
- To connect with an ASCII WEP key:
root #iw dev wlp9s0 connect -w GentooNode key 0:some-password
If the wireless network is set up with WPA or WPA2, then wpa_supplicant needs to be used. For more information on configuring wireless networking in Gentoo Linux, please read the Wireless networking chapter in the Gentoo Handbook.
Confirm the wireless settings by using iw dev wlp9s0 link. Once wireless is working, continue configuring the IP level networking options as described in the next section (Understanding network terminology) or use the net-setup tool as described previously.
Understanding network terminology
If the IP address, broadcast address, netmask and nameservers are known, then skip this subsection and continue with Using ifconfig and route.
If all of the above fails, the network will need to be configured manually. This is not difficult at all. However, some knowledge of network terminology and basic concepts might be necessary. After reading this section, users will know what a gateway is, what a netmask serves for, how a broadcast address is formed and why systems need nameservers.
In a network, hosts are identified by their IP address (Internet Protocol address). Such an address is perceived as a combination of four numbers between 0 and 255. Well, at least when using IPv4 (IP version 4). In reality, such an IPv4 address consists of 32 bits (ones and zeros). Let's view an example:
IP Address (numbers): 192.168.0.2
IP Address (bits): 11000000 10101000 00000000 00000010
-------- -------- -------- --------
192 168 0 2The successor of IPv4, IPv6, uses 128 bits (ones and zeros). In this section, the focus is on IPv4 addresses.
Such an IP address is unique to a host as far as all accessible networks are concerned (i.e. every host that one wants to be able to reach must have a unique IP address). In order to distinguish between hosts inside and outside a network, the IP address is divided in two parts: the network part and the host part.
The separation is written down with the netmask, a collection of ones followed by a collection of zeros. The part of the IP that can be mapped on the ones is the network-part, the other one is the host-part. As usual, the netmask can be written down as an IP address.
IP address: 192 168 0 2
11000000 10101000 00000000 00000010
Netmask: 11111111 11111111 11111111 00000000
255 255 255 0
+--------------------------+--------+
Network HostIn other words, 192.168.0.14 is part of the example network, but 192.168.1.2 is not.
The broadcast address is an IP address with the same network-part as the network, but with only ones as host-part. Every host on the network listens to this IP address. It is truly meant for broadcasting packets.
IP address: 192 168 0 2
11000000 10101000 00000000 00000010
Broadcast: 11000000 10101000 00000000 11111111
192 168 0 255
+--------------------------+--------+
Network HostTo be able to surf on the Internet, each computer in the network must know which host shares the Internet connection. This host is called the gateway. Since it is a regular host, it has a regular IP address (for instance 192.168.0.1).
Previously we stated that every host has its own IP address. To be able to reach this host by a name (instead of an IP address) we need a service that translates a name (such as dev.gentoo.org) to an IP address (such as 64.5.62.82). Such a service is called a name service. To use such a service, the necessary name servers need to be defined in /etc/resolv.conf.
In some cases, the gateway also serves as a nameserver. Otherwise the nameservers provided by the ISP need to be entered in this file.
To summarize, the following information is needed before continuing:
| Network item | Example |
|---|---|
| The system IP address | 192.168.0.2 |
| Netmask | 255.255.255.0 |
| Broadcast | 192.168.0.255 |
| Gateway | 192.168.0.1 |
| Nameserver(s) | 195.130.130.5, 195.130.130.133 |
Using ifconfig and route
Setting up the network consists of three steps:
- Assign an IP address using ifconfig
- Set up routing to the gateway using route
- Finish up by placing the nameserver IPs in /etc/resolv.conf
To assign an IP address, the IP address, broadcast address and netmask are needed. Then execute the following command, substituting ${IP_ADDR} with the right IP address, ${BROADCAST} with the right broadcast address and ${NETMASK} with the right netmask:
root #ifconfig eth0 ${IP_ADDR} broadcast ${BROADCAST} netmask ${NETMASK} upSet up routing using route. Substitute ${GATEWAY} with the right gateway IP address:
root #route add default gw ${GATEWAY}Now open /etc/resolv.conf:
root #nano -w /etc/resolv.confFill in the nameserver(s) using the following as a template. Make sure to substitute ${NAMESERVER1} and ${NAMESERVER2} with the appropriate nameserver addresses:
/etc/resolv.confDefault resolv.conf templatenameserver ${NAMESERVER1}
nameserver ${NAMESERVER2}
That's it. Now test the network by pinging some Internet server (like Google's 8.8.8.8 or Cloudflare's 1.1.1.1). If this works, congratulations then. Continue with Preparing the disks.
Introduction to block devices
Block devices
Let's take a good look at disk-oriented aspects of Gentoo Linux and Linux in general, including Linux filesystems, partitions, and block devices. Once the ins and outs of disks and filesystems are understood, partitions and filesystems can be established for the Gentoo Linux installation.
To begin, let's look at block devices. The most famous block device is probably the one that represents the first drive in a Linux system, namely /dev/sda. SCSI and Serial ATA drives are both labeled /dev/sd*; even IDE drives are labeled /dev/sd* with the libata framework in the kernel. When using the old device framework, then the first IDE drive is /dev/hda.
The block devices above represent an abstract interface to the disk. User programs can use these block devices to interact with the disk without worrying about whether the drives are IDE, SCSI, or something else. The program can simply address the storage on the disk as a bunch of contiguous, randomly-accessible 512-byte blocks.
Introduction to block devices
Block devices
Placeholder for introduction to block devices specific to that architecture
Designing a partition scheme
Placeholder for designing a partition scheme specific to that architecture
Creating file systems
Introduction
Now that the partitions are created, it is time to place a filesystem on them. In the next section the various file systems that Linux supports are described. Readers that already know which filesystem to use can continue with Applying a filesystem to a partition. The others should read on to learn about the available filesystems...
Filesystems
Several filesystems are available. Some of them are found stable on the architecture - it is advised to read up on the filesystems and their support state before selecting a more experimental one for important partitions.
- btrfs
- A next generation filesystem that provides many advanced features such as snapshotting, self-healing through checksums, transparent compression, subvolumes and integrated RAID. A few distributions have begun to ship it as an out-of-the-box option, but it is not production ready. Reports of filesystem corruption are common. Its developers urge people to run the latest kernel version for safety because the older ones have known problems. This has been the case for years and it is too early to tell if things have changed. Fixes for corruption issues are rarely backported to older kernels. Proceed with caution when using this filesystem!
- ext2
- This is the tried and true Linux filesystem but doesn't have metadata journaling, which means that routine ext2 filesystem checks at startup time can be quite time-consuming. There is now quite a selection of newer-generation journaled filesystems that can be checked for consistency very quickly and are thus generally preferred over their non-journaled counterparts. Journaled filesystems prevent long delays when the system is booted and the filesystem happens to be in an inconsistent state.
- ext3
- The journaled version of the ext2 filesystem, providing metadata journaling for fast recovery in addition to other enhanced journaling modes like full data and ordered data journaling. It uses an HTree index that enables high performance in almost all situations. In short, ext3 is a very good and reliable filesystem.
- ext4
- Initially created as a fork of ext3, ext4 brings new features, performance improvements, and removal of size limits with moderate changes to the on-disk format. It can span volumes up to 1 EB and with maximum file size of 16TB. Instead of the classic ext2/3 bitmap block allocation ext4 uses extents, which improve large file performance and reduce fragmentation. Ext4 also provides more sophisticated block allocation algorithms (delayed allocation and multiblock allocation) giving the filesystem driver more ways to optimize the layout of data on the disk. Ext4 is the recommended all-purpose all-platform filesystem.
- f2fs
- The Flash-Friendly File System was originally created by Samsung for the use with NAND flash memory. As of Q2, 2016, this filesystem is still considered immature, but it is a decent choice when installing Gentoo to microSD cards, USB drives, or other flash-based storage devices.
- JFS
- IBM's high-performance journaling filesystem. JFS is a light, fast and reliable B+tree-based filesystem with good performance in various conditions.
- ReiserFS
- A B+tree-based journaled filesystem that has good overall performance, especially when dealing with many tiny files at the cost of more CPU cycles. ReiserFS appears to be less maintained than other filesystems.
- XFS
- A filesystem with metadata journaling which comes with a robust feature-set and is optimized for scalability. XFS seems to be less forgiving to various hardware problems.
- vfat
- Also known as FAT32, is supported by Linux but does not support any permission settings. It is mostly used for interoperability with other operating systems (mainly Microsoft Windows) but is also a necessity for some system firmware (like UEFI).
- NTFS
- This "New Technology" filesystem is the flagship filesystem of Microsoft Windows. Similar to vfat above it does not store permission settings or extended attributes necessary for BSD or Linux to function properly, therefore it cannot be used as a root filesystem. It should only be used for interoperability with Microsoft Windows systems (note the emphasis on only).
When using ext2, ext3, or ext4 on a small partition (less than 8GB), then the file system must be created with the proper options to reserve enough inodes. The mke2fs (mkfs.ext2) application uses the "bytes-per-inode" setting to calculate how many inodes a file system should have. On smaller partitions, it is advised to increase the calculated number of inodes.
On ext2, ext3 and ext4, this can be done using one of the following commands, respectively:
root #mkfs.ext2 -T small /dev/<device>root #mkfs.ext3 -T small /dev/<device>root #mkfs.ext4 -T small /dev/<device>This will generally quadruple the number of inodes for a given file system as its "bytes-per-inode" reduces from one every 16kB to one every 4kB. This can be tuned even further by providing the ratio:
root #mkfs.ext2 -i <ratio> /dev/<device>Applying a filesystem to a partition
To create a filesystem on a partition or volume, there are user space utilities available for each possible filesystem. Click the filesystem's name in the table below for additional information on each filesystem:
| Filesystem | Creation command | On minimal CD? | Package |
|---|---|---|---|
| btrfs | mkfs.btrfs | Yes | sys-fs/btrfs-progs |
| ext2 | mkfs.ext2 | Yes | sys-fs/e2fsprogs |
| ext3 | mkfs.ext3 | Yes | sys-fs/e2fsprogs |
| ext4 | mkfs.ext4 | Yes | sys-fs/e2fsprogs |
| f2fs | mkfs.f2fs | Yes | sys-fs/f2fs-tools |
| jfs | mkfs.jfs | Yes | sys-fs/jfsutils |
| reiserfs | mkfs.reiserfs | Yes | sys-fs/reiserfsprogs |
| xfs | mkfs.xfs | Yes | sys-fs/xfsprogs |
| vfat | mkfs.vfat | Yes | sys-fs/dosfstools |
| NTFS | mkfs.ntfs | Yes | sys-fs/ntfs3g |
For instance, to have the root partition () in ext4 as used in the example partition structure, the following commands would be used:
root #mkfs.ext4 Now create the filesystems on the newly created partitions (or logical volumes).
Activating the swap partition
mkswap is the command that is used to initialize swap partitions:
root #mkswap To activate the swap partition, use swapon:
root #swapon Create and activate the swap with the commands mentioned above.
Mounting the root partition
Now that the partitions are initialized and are housing a filesystem, it is time to mount those partitions. Use the mount command, but don't forget to create the necessary mount directories for every partition created. As an example we mount the root partition:
root #mount /mnt/gentooIf /tmp/ needs to reside on a separate partition, be sure to change its permissions after mounting:
root #chmod 1777 /mnt/gentoo/tmpLater in the instructions the proc filesystem (a virtual interface with the kernel) as well as other kernel pseudo-filesystems will be mounted. But first we install the Gentoo installation files.
Installing a stage tarball
Setting the date and time
Before installing Gentoo, it is a good idea to be sure the date and time are set correctly. A mis-configured clock may lead to strange results: base system files should be extracted with accurate time stamps. In fact, due to several websites and services using encrypted communications (SSL/TLS), it might not be possible to download the installation files at all if the system clock is too far skewed!
Verify the current date and time by running the date command:
root #dateMon Oct 3 13:16:22 PDT 2016
If the date/time displayed is wrong, update it using one of the methods below.
Motherboards that do not include a Real-Time Clock (RTC) should be configured to automatically sync the system clock with a time server. This is also true for systems that do include a RTC, but have a failed battery.
Automatic
Official Gentoo installation media includes the ntpd command (available through the net-misc/ntp package). Official media includes a configuration file pointing to ntp.org time servers. It can be used to automatically sync the system clock to UTC time using a time server. Using this method requires a working network configuration and may not be available on all architectures.
Automatic time sync comes at a price. It will reveal the system's IP address and related network information to a time server (in the case of the example below ntp.org). Users with privacy concerns should be aware of this before setting the system clock using the below method.
root #ntpd -q -gManual
The date command can also be used to perform a manual set on the system clock. Use the MMDDhhmmYYYY syntax (Month, Day, hour, minute and Year).
UTC time is recommended for all Linux systems. Later on during the installation a timezone will be defined. This will modify the display of the clock to local time.
For instance, to set the date to October 3rd, 13:16 in the year 2016:
root #date 100313162016Choosing a stage tarball
Multilib (32 and 64-bit)
Choosing a base tarball for the system can save a considerable amount of time later on in the installation process, specifically when it is time to choose a system profile. The selection of a stage tarball will directly impact future system configuration and can save a headache or two later on down the line. The multilib tarball uses 64-bit libraries when possible, and only falls back to the 32-bit versions when necessary for compatibility. This is an excellent option for the majority of installations because it provides a great amount of flexibility for customization in the future. Those who desire their systems to be capable of easily switching profiles should download the multilib tarball option for their respective processor architecture.
Most users should not use the 'advanced' tarballs options; they are for specific software or hardware configurations.
No-multilib (pure 64-bit)
Selecting a no-multilib tarball to be the base of the system provides a complete 64-bit operating system environment. This effectively renders the ability to switch to multilib profiles improbable, but possible. Those who are just starting out with Gentoo should not choose a no-multilib tarball unless it is absolutely necessary.
Be aware, migrating from a no-multilib to a multilib system requires an extremely well-working knowledge of Gentoo and the lower-level toolchain (it may even cause our Toolchain developers to shudder a little). It is not for the faint of heart and is beyond the scope of this guide.
Downloading the stage tarball
Go to the Gentoo mount point where the root file system is mounted (most likely /mnt/gentoo):
root #cd /mnt/gentooDepending on the installation medium, the only tool necessary to download a stage tarball is a web browser.
Graphical browsers
Those using environments with fully graphical web browsers will have no problem copying a stage file URL from the main website's download section. Simply select the appropriate tab, right click the link to the stage file, then Copy link address (Firefox) or Copy link location (Chromium) to copy the link to the clipboard, then paste the link to the wget utility on the command-line to download the stage tarball:
root #wget <PASTED_STAGE_URL>Command-line browsers
More traditional readers or 'old timer' Gentoo users, working exclusively from command-line may prefer using links, a non-graphical, menu-driven browser. To download a stage, surf to the Gentoo mirror list like so:
root #links https://www.gentoo.org/downloads/mirrors/To use an HTTP proxy with links, pass on the URL with the -http-proxy option:
root #links -http-proxy proxy.server.com:8080 https://www.gentoo.org/downloads/mirrors/Next to links there is also the lynx browser. Like links it is a non-graphical browser but it is not menu-driven.
root #lynx https://www.gentoo.org/downloads/mirrors/If a proxy needs to be defined, export the http_proxy and/or ftp_proxy variables:
root #export http_proxy="http://proxy.server.com:port"
root #export ftp_proxy="http://proxy.server.com:port"On the mirror list, select a mirror close by. Usually HTTP mirrors suffice, but other protocols are available as well. Move to the releases//autobuilds/ directory. There all available stage files are displayed (they might be stored within subdirectories named after the individual sub-architectures). Select one and press d to download.
After the stage file download completes, it is possible to verify the integrity and validate the contents of the stage tarball. Those interested should proceed to the next section.
Those not interested in verifying and validating the stage file can close the command-line browser by pressing q and can move directly to the Unpacking the stage tarball section.
Verifying and validating
Some tarballs are being delivered via xz compression. When downloading a tarball ending in .tar.xz, be sure to adjust the tarball filename from .tar.bz2 in the following commands.
Like with the minimal installation CDs, additional downloads to verify and validate the stage file are available. Although these steps may be skipped, these files are provided for users who care about the legitimacy of the file(s) they just downloaded.
- A .CONTENTS file that contains a list of all files inside the stage tarball.
- A .DIGESTS file that contains checksums of the stage file in different algorithms.
- A .DIGESTS.asc file that, like the .DIGESTS file, contains checksums of the stage file in different algorithms, but is also cryptographically signed to ensure it is provided by the Gentoo project.
Use openssl and compare the output with the checksums provided by the .DIGESTS or .DIGESTS.asc files.
For instance, to validate the SHA512 checksum:
root #openssl dgst -r -sha512 stage3--<release>.tar.?(bz2|xz)Another way is to use the sha512sum command:
root #sha512sum stage3--<release>.tar.?(bz2|xz)To validate the Whirlpool checksum:
root #openssl dgst -r -whirlpool stage3--<release>.tar.?(bz2|xz)Compare the output of these commands with the value registered in the .DIGESTS(.asc) files. The values need to match, otherwise the downloaded file might be corrupt (or the digests file is).
Just like with the ISO file, it is also possible to verify the cryptographic signature of the .DIGESTS.asc file using gpg to make sure the checksums have not been tampered with:
root #gpg --verify stage3--<release>.tar.?(bz2|xz){.DIGESTS.asc,} Unpacking the stage tarball
Now unpack the downloaded stage onto the system. We use tar to proceed:
root #tar xpvf stage3-*.tar.bz2 --xattrs-include='*.*' --numeric-ownerMake sure that the same options (xpf and --xattrs-include='*.*') are used. The x stands for extract, the p for preserve permissions and the f to denote that we want to extract a file (not standard input). --xattrs-include='*.*' is to include preservation of the the extended attributes in all namespaces stored in the archive. Finally, --numeric-owner is used to ensure that the user and group IDs of the files being extracted from the tarball will remain the same as Gentoo's release engineering team intended (even if adventurous users are not using official Gentoo installation media).
Now that the stage file is unpacked, proceed with Configuring the compile options.
Configuring compile options
Introduction
To optimize Gentoo, it is possible to set a couple of variables which impacts the behavior of Portage, Gentoo's officially supported package manager. All those variables can be set as environment variables (using export) but that isn't permanent. To keep the settings, Portage reads in the /etc/portage/make.conf file, a configuration file for Portage.
A commented listing of all possible variables can be found in /mnt/gentoo/usr/share/portage/config/make.conf.example. For a successful Gentoo installation only the variables that are mentioned below need to be set.
Fire up an editor (in this guide we use nano) to alter the optimization variables we will discuss hereafter.
root #nano -w /mnt/gentoo/etc/portage/make.confFrom the make.conf.example file it is obvious how the file should be structured: commented lines start with "#", other lines define variables using the VARIABLE="content" syntax. Several of those variables are discussed next.
CFLAGS and CXXFLAGS
The CFLAGS and CXXFLAGS variables define the optimization flags for GCC C and C++ compilers respectively. Although those are defined generally here, for maximum performance one would need to optimize these flags for each program separately. The reason for this is because every program is different. However, this is not manageable, hence the definition of these flags in the make.conf file.
In make.conf one should define the optimization flags that will make the system the most responsive generally. Don't place experimental settings in this variable; too much optimization can make programs behave bad (crash, or even worse, malfunction).
We will not explain all possible optimization options. To understand them all, read the GNU Online Manual(s) or the gcc info page (info gcc - only works on a working Linux system). The make.conf.example file itself also contains lots of examples and information; don't forget to read it too.
A first setting is the -march= or -mtune= flag, which specifies the name of the target architecture. Possible options are described in the make.conf.example file (as comments). A commonly used value is native as that tells the compiler to select the target architecture of the current system (the one users are installing Gentoo on).
A second one is the -O flag (that is a capital O, not a zero), which specifies the gcc optimization class flag. Possible classes are s (for size-optimized), 0 (zero - for no optimizations), 1, 2 or even 3 for more speed-optimization flags (every class has the same flags as the one before, plus some extras). -O2 is the recommended default. -O3 is known to cause problems when used system-wide, so we recommend to stick to -O2.
Another popular optimization flag is -pipe (use pipes rather than temporary files for communication between the various stages of compilation). It has no impact on the generated code, but uses more memory. On systems with low memory, gcc might get killed. In that case, do not use this flag.
Using -fomit-frame-pointer (which doesn't keep the frame pointer in a register for functions that don't need one) might have serious repercussions on the debugging of applications.
When the CFLAGS and CXXFLAGS variables are defined, combine the several optimization flags in one string. The default values contained in the stage3 archive that is unpacked should be good enough. The following one is just an example:
# Compiler flags to set for all languages COMMON_FLAGS="" # Use the same settings for both variables CFLAGS="${COMMON_FLAGS}" CXXFLAGS="${COMMON_FLAGS}"
Although the GCC optimization article has more information on how the various compilation options can affect a system, the Safe CFLAGS article may be a more practical place for beginners to start optimizing their systems.
MAKEOPTS
The MAKEOPTS variable defines how many parallel compilations should occur when installing a package. A good choice is the number of CPUs (or CPU cores) in the system plus one, but this guideline isn't always perfect.
MAKEOPTS="-j2"
Ready, set, go!
Update the /mnt/gentoo/etc/portage/make.conf file to match personal preference and save (nano users would hit Ctrl+X).
Then continue with Installing the Gentoo base system.
Chrooting
Optional: Selecting mirrors
Distribution files
In order to download source code quickly it is recommended to select a fast mirror. Portage will look in the make.conf file for the GENTOO_MIRRORS variable and use the mirrors listed therein. It is possible to surf to the Gentoo mirror list and search for a mirror (or mirrors) that is close to the system's physical location (as those are most frequently the fastest ones). However, we provide a nice tool called mirrorselect which provides users with a nice interface to select the mirrors needed. Just navigate to the mirrors of choice and press Spacebar to select one or more mirrors.
root #mirrorselect -i -o >> /mnt/gentoo/etc/portage/make.confGentoo ebuild repository
A second important step in selecting mirrors is to configure the Gentoo ebuild repository via the /etc/portage/repos.conf/gentoo.conf file. This file contains the sync information needed to update the package repository (the collection of ebuilds and related files containing all the information Portage needs to download and install software packages).
Configuring the repository can be done in a few simple steps. First, if it does not exist, create the repos.conf directory:
root #mkdir --parents /mnt/gentoo/etc/portage/repos.confNext, copy the Gentoo repository configuration file provided by Portage to the (newly created) repos.conf directory:
root #cp /mnt/gentoo/usr/share/portage/config/repos.conf /mnt/gentoo/etc/portage/repos.conf/gentoo.confTake a peek with a text editor or by using the cat command. The inside of the file should be in .ini format and look like this:
/mnt/gentoo/etc/portage/repos.conf/gentoo.conf[DEFAULT] main-repo = gentoo [gentoo] location = /usr/portage sync-type = rsync sync-uri = rsync://rsync.gentoo.org/gentoo-portage auto-sync = yes sync-rsync-verify-jobs = 1 sync-rsync-verify-metamanifest = yes sync-rsync-verify-max-age = 24 sync-openpgp-key-path = /usr/share/openpgp-keys/gentoo-release.asc sync-openpgp-key-refresh-retry-count = 40 sync-openpgp-key-refresh-retry-overall-timeout = 1200 sync-openpgp-key-refresh-retry-delay-exp-base = 2 sync-openpgp-key-refresh-retry-delay-max = 60 sync-openpgp-key-refresh-retry-delay-mult = 4 # for daily squashfs snapshots #sync-type = squashdelta #sync-uri = mirror://gentoo/../snapshots/squashfs
The default sync-uri variable value listed above will determine a mirror location based on a rotation. This will aid in easing bandwidth stress on Gentoo's infrastructure and will provide a fail-safe in case a specific mirror is offline. It is recommended the default URI is retained unless a local, private Portage mirror will be used.
For those interested, the official specification for Portage's plug-in sync API can be found in the Portage project's Sync article.
Copy DNS info
One thing still remains to be done before entering the new environment and that is copying over the DNS information in /etc/resolv.conf. This needs to be done to ensure that networking still works even after entering the new environment. /etc/resolv.conf contains the name servers for the network.
To copy this information, it is recommended to pass the --dereference option to the cp command. This ensures that, if /etc/resolv.conf is a symbolic link, that the link's target file is copied instead of the symbolic link itself. Otherwise in the new environment the symbolic link would point to a non-existing file (as the link's target is most likely not available inside the new environment).
root #cp --dereference /etc/resolv.conf /mnt/gentoo/etc/Mounting the necessary filesystems
In a few moments, the Linux root will be changed towards the new location. To make sure that the new environment works properly, certain filesystems need to be made available there as well.
The filesystems that need to be made available are:
- /proc/ which is a pseudo-filesystem (it looks like regular files, but is actually generated on-the-fly) from which the Linux kernel exposes information to the environment
- /sys/ which is a pseudo-filesystem, like /proc/ which it was once meant to replace, and is more structured than /proc/
- /dev/ is a regular file system, partially managed by the Linux device manager (usually udev), which contains all device files
The /proc/ location will be mounted on /mnt/gentoo/proc/ whereas the other two are bind-mounted. The latter means that, for instance, /mnt/gentoo/sys/ will actually be /sys/ (it is just a second entry point to the same filesystem) whereas /mnt/gentoo/proc/ is a new mount (instance so to speak) of the filesystem.
root #mount --types proc /proc /mnt/gentoo/proc
root #mount --rbind /sys /mnt/gentoo/sys
root #mount --make-rslave /mnt/gentoo/sys
root #mount --rbind /dev /mnt/gentoo/dev
root #mount --make-rslave /mnt/gentoo/dev
The
--make-rslave operations are needed for systemd support later in the installation.When using non-Gentoo installation media, this might not be sufficient. Some distributions make /dev/shm a symbolic link to /run/shm/ which, after the chroot, becomes invalid. Making /dev/shm/ a proper tmpfs mount up front can fix this:
root #test -L /dev/shm && rm /dev/shm && mkdir /dev/shm
root #mount --types tmpfs --options nosuid,nodev,noexec shm /dev/shm
Also ensure that mode 1777 is set:
root # chmod 1777 /dev/shmEntering the new environment
Now that all partitions are initialized and the base environment installed, it is time to enter the new installation environment by chrooting into it. This means that the session will change its root (most top-level location that can be accessed) from the current installation environment (installation CD or other installation medium) to the installation system (namely the initialized partitions). Hence the name, change root or chroot.
This chrooting is done in three steps:
- The root location is changed from / (on the installation medium) to /mnt/gentoo/ (on the partitions) using chroot
- Some settings (those in /etc/profile) are reloaded in memory using the source command
- The primary prompt is changed to help us remember that this session is inside a chroot environment.
root #chroot /mnt/gentoo /bin/bash
root #source /etc/profile
root #export PS1="(chroot) ${PS1}"From this point, all actions performed are immediately on the new Gentoo Linux environment. Of course it is far from finished, which is why the installation still has some sections left!
If the Gentoo installation is interrupted anywhere after this point, it should be possible to 'resume' the installation at this step. There is no need to repartition the disks again! Simply mount the root partition and run the steps above starting with copying the DNS info to re-enter the working environment. This is also useful for fixing bootloader issues. More information can be found in the chroot article.
Configuring Portage
Installing an ebuild repository snapshot from the web
Next step is to install a snapshot of the main ebuild repository. This snapshot contains a collection of files that informs Portage about available software titles (for installation), which profiles the system administrator can select, package or profile specific news items, etc.
The use of emerge-webrsync is recommended for those who are behind restrictive firewalls (because it uses HTTP/FTP protocols for downloading the snapshot) and saves network bandwidth. Readers who have no network or bandwidth restrictions can happily skip down to the next section.
This will fetch the latest snapshot (which is released on a daily basis) from one of Gentoo's mirrors and install it onto the system:
root #emerge-webrsyncDuring this operation, emerge-webrsync might complain about a missing /usr/portage/ location. This is to be expected and nothing to worry about - the tool will create the location.
From this point onward, Portage might mention that certain updates are recommended to be executed. This is because system packages installed through the stage file might have newer versions available; Portage is now aware of new packages because of the repository snapshot. Package updates can be safely ignored for now; updates can be delayed after the Gentoo installation has finished.
Optional: Updating the Gentoo ebuild repository
It is possible to update the Gentoo ebuild repository to the latest version. The previous emerge-webrsync command will have installed a very recent snapshot (usually recent up to 24h) so this step is definitely optional.
Suppose there is a need for the last package updates (up to 1 hour), then use emerge --sync. This command will use the rsync protocol to update the Gentoo ebuild repository (which was fetched earlier on through emerge-webrsync) to the latest state.
root #emerge --syncOn slow terminals, like some framebuffers or serial consoles, it is recommended to use the --quiet option to speed up the process:
root #emerge --sync --quietReading news items
When the Gentoo ebuild repository is synchronized to the system, Portage may warn the user with messages similar to the following:
* IMPORTANT: 2 news items need reading for repository 'gentoo'.
* Use eselect news to read news items.
News items were created to provide a communication medium to push critical messages to users via the rsync tree. To manage them, use eselect news. The eselect application is a Gentoo application that allows for a common management interface towards system changes and operations. In this case, eselect is asked to use its news module.
For the news module, three operations are most used:
- With
listan overview of the available news items is displayed. - With
readthe news items can be read. - With
purgenews items can be removed once they have been read and will not be reread anymore.
root #eselect news list
root #eselect news readMore information about the newsreader is available through its manual page:
root #man news.eselectChoosing the right profile
Do not select any of the the 17.1 profiles until reading the corresponding 17.1 news item. This profile is experimental and requires special migration instructions.
A profile is a building block for any Gentoo system. Not only does it specify default values for USE, CFLAGS, and other important variables, it also locks the system to a certain range of package versions. These settings are all maintained by Gentoo's Portage developers.
You can see what profile the system is currently using with eselect, now using the profile module:
root #eselect profile listAvailable profile symlink targets: [1] default/linux//13.0 * [2] default/linux//13.0/desktop [3] default/linux//13.0/desktop/gnome [4] default/linux//13.0/desktop/kde
The output of the command is just an example and evolves over time.
As can be seen, there are also desktop subprofiles available for some architectures.
Profile upgrades are not to be taken lightly. When selecting the initial profile, make sure to use profile corresponding to the same version as the one initially used by stage3 (e.g. 13.0). Each new profile version is announced through a news item containing migration instructions. Make sure to read it and follow them before switching to a newer profile.
After viewing the available profiles for the architecture, users can select a different profile for the system:
root #eselect profile set 2This is a placeholder for architecture-specific profile information
The
developer subprofile is specifically for Gentoo Linux development and is not meant to be used by casual users.Updating the @world set
At this point, it is wise to update the system's @world set so that a base can be established.
This following step is necessary so the system can apply any updates or USE flag changes which have appeared since the stage3 was built and from any profile selection:
root #emerge --ask --verbose --update --deep --newuse @worldIf a full scale desktop environment profile has been selected this process could greatly extend the amount of time necessary for the install process. Those in a time crunch can work by this 'rule of thumb': the shorter the profile name, the less specific the system's @world set; the less specific the @world set, the fewer packages the system will require. In other words:
- selecting
default/linux/amd64/13.0will require very few packages to be updated, whereas - selecting
default/linux/amd64/13.0/desktop/gnome/systemdwill require many packages to be installed since the init system is changing from OpenRC to systemd, and the GNOME desktop environment framework will be installed.
Configuring the USE variable
USE is one of the most powerful variables Gentoo provides to its users. Several programs can be compiled with or without optional support for certain items. For instance, some programs can be compiled with support for GTK+ or with support for Qt. Others can be compiled with or without SSL support. Some programs can even be compiled with framebuffer support (svgalib) instead of X11 support (X-server).
Most distributions compile their packages with support for as much as possible, increasing the size of the programs and startup time, not to mention an enormous amount of dependencies. With Gentoo users can define what options a package should be compiled with. This is where USE comes into play.
In the USE variable users define keywords which are mapped onto compile-options. For instance, ssl will compile SSL support in the programs that support it. -X will remove X-server support (note the minus sign in front). gnome gtk -kde -qt4 -qt5 will compile programs with GNOME (and GTK+) support, and not with KDE (and Qt) support, making the system fully tweaked for GNOME (if the architecture supports it).
The default USE settings are placed in the make.defaults files of the Gentoo profile used by the system. Gentoo uses a (complex) inheritance system for its profiles, which we will not dive into at this stage. The easiest way to check the currently active USE settings is to run emerge --info and select the line that starts with USE:
root #emerge --info | grep ^USEUSE="X acl alsa amd64 berkdb bindist bzip2 cli cracklib crypt cxx dri ..."
The above example is truncated, the actual list of USE values is much, much larger.
A full description on the available USE flags can be found on the system in /usr/portage/profiles/use.desc.
root #less /usr/portage/profiles/use.descInside the less command, scrolling can be done using the ↑ and ↓ keys, and exited by pressing q.
As an example we show a USE setting for a KDE-based system with DVD, ALSA, and CD recording support:
root #nano -w /etc/portage/make.conf/etc/portage/make.confEnabling USE for a KDE-based system with DVD, ALSA and CD recording supportUSE="-gtk -gnome qt4 qt5 kde dvd alsa cdr"
When USE is defined in /etc/portage/make.conf it is added (or removed if the USE flag starts with the - sign) from that default list. Users who want to ignore any default USE settings and manage it completely themselves should start the USE definition in make.conf with -*:
/etc/portage/make.confIgnoring default USE flagsUSE="-* X acl alsa"
Although possible, setting
-* (as seen in the example above) is discouraged as carefully chosen USE flag defaults may be configured in some ebuilds to prevent conflicts and other errors.
Timezone
Select the timezone for the system. Look for the available timezones in /usr/share/zoneinfo/, then write it in the /etc/timezone file.
root #ls /usr/share/zoneinfoSuppose the timezone of choice is Europe/Brussels:
root #echo "Europe/Brussels" > /etc/timezonePlease avoid the /usr/share/zoneinfo/Etc/GMT* timezones as their names do not indicate the expected zones. For instance, GMT-8 is in fact GMT+8.
Next, reconfigure the sys-libs/timezone-data package, which will update the /etc/localtime file for us, based on the /etc/timezone entry. The /etc/localtime file is used by the system C library to know the timezone the system is in.
root #emerge --config sys-libs/timezone-dataConfigure locales
Most users will want to use only one or two locales on their system.
Locales specify not only the language that the user should use to interact with the system, but also what the rules are for sorting strings, displaying dates and times, etc.
The locales that a system should support should be mentioned in /etc/locale.gen.
root #nano -w /etc/locale.genThe following locales are an example to get both English (United States) and German (Germany) with the accompanying character formats (like UTF-8).
/etc/locale.genEnabling US and DE locales with the appropriate character formatsen_US ISO-8859-1 en_US.UTF-8 UTF-8 de_DE ISO-8859-1 de_DE.UTF-8 UTF-8
We strongly suggest to use at least one UTF-8 locale because some applications may require it.
The next step is to run locale-gen. It will generate all the locales specified in the /etc/locale.gen file.
root #locale-genTo verify that the selected locales are now available, run locale -a.
Once done, it is now time to set the system-wide locale settings. Again we use eselect for this, now with the locale module.
With eselect locale list, the available targets are displayed:
root #eselect locale listAvailable targets for the LANG variable: [1] C [2] POSIX [3] en_US [4] en_US.iso88591 [5] en_US.utf8 [6] de_DE [7] de_DE.iso88591 [8] de_DE.iso885915 [9] de_DE.utf8 [ ] (free form)
With eselect locale set VALUE the correct locale can be set:
root #eselect locale set 9Manually, this can still be accomplished through the /etc/env.d/02locale file:
/etc/env.d/02localeManually setting system locale definitionsLANG="de_DE.UTF-8" LC_COLLATE="C"
Make sure a locale is set, as the system would otherwise display warnings and errors during kernel builds and other software deployments later in the installation.
Now reload the environment:
root #env-update && source /etc/profile && export PS1="(chroot) $PS1"We made a full Localization guide to help the user guide through this process. Another interesting article is the UTF-8 guide for very specific information to enable UTF-8 on the system.
Installing the sources
The core around which all distributions are built is the Linux kernel. It is the layer between the user programs and the system hardware. Gentoo provides its users several possible kernel sources. A full listing with description is available at the Kernel overview page.
For -based systems Gentoo recommends the sys-kernel/ package.
Choose an appropriate kernel source and install it using emerge:
root #emerge --ask sys-kernel/This will install the Linux kernel sources in /usr/src/ in which a symbolic link called linux will be pointing to the installed kernel source:
root #ls -l /usr/src/linuxlrwxrwxrwx 1 root root 12 Oct 13 11:04 /usr/src/linux -> linux-
Now it is time to configure and compile the kernel sources. There are two approaches for this:
- The kernel is manually configured and built.
- A tool called genkernel is used to automatically build and install the Linux kernel.
We explain the manual configuration as the default choice here as it is the best way to optimize an environment.
Default: Manual configuration
Introduction
Manually configuring a kernel is often seen as the most difficult procedure a Linux user ever has to perform. Nothing is less true - after configuring a couple of kernels no-one even remembers that it was difficult ;)
However, one thing is true: it is vital to know the system when a kernel is configured manually. Most information can be gathered by emerging sys-apps/pciutils which contains the lspci command:
root #emerge --ask sys-apps/pciutilsInside the chroot, it is safe to ignore any pcilib warnings (like pcilib: cannot open /sys/bus/pci/devices) that lspci might throw out.
Another source of system information is to run lsmod to see what kernel modules the installation CD uses as it might provide a nice hint on what to enable.
Now go to the kernel source directory and execute make menuconfig. This will fire up menu-driven configuration screen.
root #cd /usr/src/linux
root #make menuconfigThe Linux kernel configuration has many, many sections. Let's first list some options that must be activated (otherwise Gentoo will not function, or not function properly without additional tweaks). We also have a Gentoo kernel configuration guide on the Gentoo wiki that might help out further.
Activating required options
Make sure that every driver that is vital to the booting of the system (such as SCSI controller, etc.) is compiled in the kernel and not as a module, otherwise the system will not be able to boot completely.
Next select the exact processor type. It is also recommended to enable MCE features (if available) so that users are able to be notified of any hardware problems. On some architectures (such as x86_64), these errors are not printed to dmesg, but to /dev/mcelog. This requires the app-admin/mcelog package.
Also select Maintain a devtmpfs file system to mount at /dev so that critical device files are already available early in the boot process (CONFIG_DEVTMPFS and CONFIG_DEVTMPFS_MOUNT):
Device Drivers ---> Generic Driver Options ---> [*] Maintain a devtmpfs filesystem to mount at /dev [ ] Automount devtmpfs at /dev, after the kernel mounted the rootfs
Verify SCSI disk support has been activated (CONFIG_BLK_DEV_SD):
Device Drivers ---> SCSI device support ---> <*> SCSI disk support
Now go to File Systems and select support for the filesystems you use. Don't compile the file system that is used for the root filesystem as module, otherwise the Gentoo system will not be able to mount the partition. Also select Virtual memory and /proc file system. Select one or more of the following options as needed by the system (CONFIG_EXT2_FS, CONFIG_EXT3_FS, CONFIG_EXT4_FS, CONFIG_MSDOS_FS, CONFIG_VFAT_FS, CONFIG_PROC_FS, and CONFIG_TMPFS):
File systems ---> <*> Second extended fs support <*> The Extended 3 (ext3) filesystem <*> The Extended 4 (ext4) filesystem <*> Reiserfs support <*> JFS filesystem support <*> XFS filesystem support <*> Btrfs filesystem support DOS/FAT/NT Filesystems ---> <*> MSDOS fs support <*> VFAT (Windows-95) fs support Pseudo Filesystems ---> [*] /proc file system support [*] Tmpfs virtual memory file system support (former shm fs)
If PPPoE is used to connect to the Internet, or a dial-up modem, then enable the following options (CONFIG_PPP, CONFIG_PPP_ASYNC, and CONFIG_PPP_SYNC_TTY):
Device Drivers ---> Network device support ---> <*> PPP (point-to-point protocol) support <*> PPP support for async serial ports <*> PPP support for sync tty ports
The two compression options won't harm but are not definitely needed, neither does the PPP over Ethernet option, that might only be used by ppp when configured to do kernel mode PPPoE.
Don't forget to include support in the kernel for the network (Ethernet or wireless) cards.
Most systems also have multiple cores at their disposal, so it is important to activate Symmetric multi-processing support (CONFIG_SMP):
Processor type and features ---> [*] Symmetric multi-processing support
In multi-core systems, each core counts as one processor.
If USB input devices (like keyboard or mouse) or other USB devices will be used, do not forget to enable those as well (CONFIG_HID_GENERIC and CONFIG_USB_HID, CONFIG_USB_SUPPORT, CONFIG_USB_XHCI_HCD, CONFIG_USB_EHCI_HCD, CONFIG_USB_OHCI_HCD):
Device Drivers ---> HID support ---> -*- HID bus support <*> Generic HID driver [*] Battery level reporting for HID devices USB HID support ---> <*> USB HID transport layer [*] USB support ---> <*> xHCI HCD (USB 3.0) support <*> EHCI HCD (USB 2.0) support <*> OHCI HCD (USB 1.1) support
Architecture specific kernel configurations
Placeholder for architecture-specific kernel build information
Compiling and installing
Placeholder for instructions for building and installing the kernel sources
Optional: Building an initramfs
In certain cases it is necessary to build an initramfs - an initial ram-based file system. The most common reason is when important file system locations (like /usr/ or /var/) are on separate partitions. With an initramfs, these partitions can be mounted using the tools available inside the initramfs.
Without an initramfs, there is a huge risk that the system will not boot up properly as the tools that are responsible for mounting the file systems need information that resides on those file systems. An initramfs will pull in the necessary files into an archive which is used right after the kernel boots, but before the control is handed over to the init tool. Scripts on the initramfs will then make sure that the partitions are properly mounted before the system continues booting.
To install an initramfs, install sys-kernel/genkernel first, then have it generate an initramfs:
root #emerge --ask sys-kernel/genkernelroot #genkernel --install initramfsIn order to enable specific support in the initramfs, such as LVM or RAID, add in the appropriate options to genkernel. See genkernel --help for more information. In the next example support is enabled for LVM and software RAID (mdadm):
root #genkernel --lvm --mdadm --install initramfsThe initramfs will be stored in /boot/. The resulting file can be found by simply listing the files starting with initramfs:
root #ls /boot/initramfs*Now continue with Kernel modules.
Alternative: Using genkernel
If a manual configuration looks too daunting, then using genkernel is recommended. It will configure and build the kernel automatically.
genkernel works by configuring a kernel nearly identically to the way the installation CD kernel is configured. This means that when genkernel is used to build the kernel, the system will generally detect all hardware at boot-time, just like the installation CD does. Because genkernel doesn't require any manual kernel configuration, it is an ideal solution for those users who may not be comfortable compiling their own kernels.
Now, let's see how to use genkernel. First, emerge the sys-kernel/genkernel ebuild:
root #emerge --ask sys-kernel/genkernelNext, edit the /etc/fstab file so that the line containing /boot/ as second field has the first field pointing to the right device. If the partitioning example from the handbook is followed, then this device is most likely with the ext2 file system. This would make the entry in the file look like so:
root #nano -w /etc/fstab/etc/fstabConfiguring the /boot mountpoint/boot ext2 defaults 0 2
Further in the Gentoo installation, /etc/fstab will be configured again. The /boot setting is needed right now as the genkernel application reads in this configuration.
Now, compile the kernel sources by running genkernel all. Be aware though, as genkernel compiles a kernel that supports almost all hardware, this compilation will take quite a while to finish!
If the boot partition doesn't use ext2 or ext3 as filesystem it might be necessary to manually configure the kernel using genkernel --menuconfig all and add support for this particular filesystem in the kernel (i.e. not as a module). Users of LVM2 will probably want to add
--lvm as an argument as well.root #genkernel allOnce genkernel completes, a kernel, full set of modules and initial ram disk (initramfs) will be created. We will use the kernel and initrd when configuring a boot loader later in this document. Write down the names of the kernel and initrd as this information is used when the boot loader configuration file is edited. The initrd will be started immediately after booting to perform hardware autodetection (just like on the installation CD) before the "real" system starts up.
root #ls /boot/kernel* /boot/initramfs*Kernel modules
Configuring the modules
Hardware modules are optional to be listed manually. udev will normally load all hardware modules that are detected to be connected in most cases. However, it is not harmful for automatically detected modules to be listed. Sometimes exotic hardware requires help to load their drivers.
List the modules that need to be loaded automatically in /etc/modules-load.d/*.conf files one module per line. Extra options for the modules, if necessary, should be set in /etc/modprobe.d/*.conf files.
To view all available modules, run the following find command. Don't forget to substitute "<kernel version>" with the version of the kernel just compiled:
root #find /lib/modules/<kernel version>/ -type f -iname '*.o' -or -iname '*.ko' | lessFor instance, to automatically load the 3c59x.ko module (which is the driver for a specific 3Com network card family), edit the /etc/modules-load.d/network.conf file and enter the module name in it. The actual file name is insignificant to the loader.
root #mkdir -p /etc/modules-load.d
root #nano -w /etc/modules-load.d/network.conf
/etc/modules-load.d/network.confForce loading 3c59x module3c59x
Continue the installation with Configuring the system.
Optional: Installing firmware
Some drivers require additional firmware to be installed on the system before they work. This is often the case for network interfaces, especially wireless network interfaces. Also, modern video chips, from vendors like AMD, NVidia, and Intel when using open source drivers, often need external firmware files. Most of the firmware is packaged in sys-kernel/linux-firmware:
root #emerge --ask sys-kernel/linux-firmware
Filesystem information
About fstab
Under Linux, all partitions used by the system must be listed in /etc/fstab. This file contains the mount points of those partitions (where they are seen in the file system structure), how they should be mounted and with what special options (automatically or not, whether users can mount them or not, etc.)
Creating the fstab file
The /etc/fstab file uses a table-like syntax. Every line consists of six fields, separated by whitespace (space(s), tabs or a mixture). Each field has its own meaning:
- The first field shows the block special device or remote filesystem to be mounted. Several kinds of device identifiers are available for block special device nodes, including paths to device files, filesystem labels and UUIDs, and partition labels and UUIDs.
- The second field shows the mount point at which the partition should be mounted.
- The third field shows the filesystem used by the partition.
- The fourth field shows the mount options used by mount when it wants to mount the partition. As every filesystem has its own mount options, users are encouraged to read the mount man page (man mount) for a full listing. Multiple mount options are comma-separated.
- The fifth field is used by dump to determine if the partition needs to be dumped or not. This can generally be left as 0 (zero).
- The sixth field is used by fsck to determine the order in which filesystems should be checked if the system wasn't shut down properly. The root filesystem should have 1 while the rest should have 2 (or 0 if a filesystem check isn't necessary).
The default /etc/fstab file provided by Gentoo is not a valid fstab file but instead more of a template.
root #nano -w /etc/fstabIn the remainder of the text, we use the default /dev/sd* block device files as partition.
Filesystem labels and UUIDs
Both MBR (BIOS) and GPT include support for filesystem labels and filesystem UUIDs. These attributes can be defined in /etc/fstab as alternatives for the mount command to use when attempting to find and mount block devices. Filesystem labels and UUIDs are identified by the LABEL and UUID prefix and can be viewed with the blkid command:
root #blkidIf the filesystem inside a partition is wiped, then the filesystem label and the UUID values will be subsequently altered or removed.
Because of uniqueness, readers that are using an MBR-style partition table are recommended to use UUIDs over labels to define mountable volumes in /etc/fstab.
Partition labels and UUIDs
Users who have gone the GPT route have a couple more 'robust' options available to define partitions in /etc/fstab. Partition labels and partition UUIDs can be used to identify the block device's individual partition(s), regardless of what filesystem has been chosen for the partition itself. Partition labels and UUIDs are identified by the PARTLABEL and PARTUUID prefixes respectively and can be viewed nicely in the terminal by running the blkid command:
root #blkidWhile not always true for partition labels, using a UUID to identify a partition in fstab provides a guarantee that the bootloader will not be confused when looking for a certain volume, even if the filesystem would be changed in the future. Using the older default block device files (/dev/sd*N) for defining the partitions in fstab is risky for systems that are restarted often and have SATA block devices added and removed regularly.
The naming for block device files depends on a number of factors, including how and in what order the disks are attached to the system. They also could show up in a different order depending on which of the devices are detected by the kernel first during the early boot process. With this being stated, unless one intends to constantly fiddle with the disk ordering, using default block device files is a simple and straightforward approach.
Add the rules that match the previously decided partitioning scheme and append rules for devices such as CD-ROM drive(s), and of course, if other partitions or drives are used, for those too.
Below is a more elaborate example of an /etc/fstab file:
/etc/fstabA full /etc/fstab examplenone swap sw 0 0 / ext4 noatime 0 1 /dev/cdrom /mnt/cdrom auto noauto,user 0 0
When auto is used in the third field, it makes the mount command guess what the filesystem would be. This is recommended for removable media as they can be created with one of many filesystems. The user option in the fourth field makes it possible for non-root users to mount the CD.
To improve performance, most users would want to add the noatime mount option, which results in a faster system since access times aren't registered (those are not needed generally anyway). This is also recommended for solid state drive (SSD) users, who should also enable the discard mount option (ext4 and btrfs only for now) which makes the TRIM command work.
Double-check the /etc/fstab file, save and quit to continue.
Networking information
Host and domain information
One of the choices the user has to make is name his/her PC. This seems to be quite easy, but lots of users are having difficulties finding the appropriate name for their Linux PC. To speed things up, know that the decision is not final - it can be changed afterwards. In the examples below, the hostname tux is used within the domain homenetwork.
root #nano -w /etc/conf.d/hostname# Set the hostname variable to the selected host name hostname="tux"
Second, if a domain name is needed, set it in /etc/conf.d/net. This is only necessary if the ISP or network administrator says so, or if the network has a DNS server but not a DHCP server. Don't worry about DNS or domain names if the system uses DHCP for dynamic IP address allocation and network configuration.
The /etc/conf.d/net file does not exist by default, so needs to be created.
root #nano -w /etc/conf.d/net# Set the dns_domain_lo variable to the selected domain name dns_domain_lo="homenetwork"
If no domain name is configured, then users will notice they get "This is hostname.(none)" messages at their login screen. This should then be fixed by editing /etc/issue and deleting the string
.\O from that file.If a NIS domain is needed (users that do not know this will not need one), define that one too:
root #nano -w /etc/conf.d/net# Set the nis_domain_lo variable to the selected NIS domain name nis_domain_lo="my-nisdomain"
For more information on configuring DNS and NIS, please read the examples provided in /usr/share/doc/netifrc-*/net.example.bz2 which can be read using bzless. Also, it might be interesting to install net-dns/openresolv to help manage the DNS/NIS setup.
Configuring the network
During the Gentoo Linux installation, networking was already configured. However, that was for the installation CD itself and not for the installed environment. Right now, the network configuration is made for the installed Gentoo Linux system.
More detailed information about networking, including advanced topics like bonding, bridging, 802.1Q VLANs or wireless networking is covered in the Gentoo Network Configuration section.
All networking information is gathered in /etc/conf.d/net. It uses a straightforward yet perhaps not intuitive syntax. But don't fear, everything is explained below. A fully commented example that covers many different configurations is available in /usr/share/doc/netifrc-*/net.example.bz2.
First install net-misc/netifrc:
root #emerge --ask --noreplace net-misc/netifrcDHCP is used by default. For DHCP to work, a DHCP client needs to be installed. This is described later in Installing Necessary System Tools.
If the network connection needs to be configured because of specific DHCP options or because DHCP is not used at all, then open /etc/conf.d/net:
root #nano -w /etc/conf.d/netSet both config_eth0 and routes_eth0 to enter IP address information and routing information:
This assumes that the network interface will be called eth0. This is, however, very system dependent. It is recommended to assume that the interface is named the same as the interface name when booted from the installation media if the installation media is sufficiently recent. More information can be found in Network Interface Naming.
/etc/conf.d/netStatic IP definitionconfig_eth0="192.168.0.2 netmask 255.255.255.0 brd 192.168.0.255" routes_eth0="default via 192.168.0.1"
To use DHCP, define config_eth0:
/etc/conf.d/netDHCP definitionconfig_eth0="dhcp"
Please read /usr/share/doc/netifrc-*/net.example.bz2 for a list of all available options. Be sure to also read up on the DHCP client man page if specific DHCP options need to be set.
If the system has several network interfaces, then repeat the above steps for config_eth1, config_eth2, etc.
Now save the configuration and exit to continue.
Automatically start networking at boot
To have the network interfaces activated at boot, they need to be added to the default runlevel.
root #cd /etc/init.d
root #ln -s net.lo net.eth0
root #rc-update add net.eth0 defaultIf the system has several network interfaces, then the appropriate net.* files need to be created just like we did with net.eth0.
If after booting the system we find out that the assumption about the network interface name (which is currently documented as eth0) was wrong, then execute the following steps to rectify this:
- Update the /etc/conf.d/net file with the correct interface name (like
enp3s0instead ofeth0). - Create new symbolic link (like /etc/init.d/net.enp3s0).
- Remove the old symbolic link (rm /etc/init.d/net.eth0).
- Add the new one to the default runlevel.
- Remove the old one using rc-update del net.eth0 default.
The hosts file
Next inform Linux about the network environment. This is defined in /etc/hosts and helps in resolving host names to IP addresses for hosts that aren't resolved by the nameserver.
root #nano -w /etc/hosts/etc/hostsFilling in the networking information# This defines the current system and must be set 127.0.0.1 tux.homenetwork tux localhost # Optional definition of extra systems on the network 192.168.0.5 jenny.homenetwork jenny 192.168.0.6 benny.homenetwork benny
Save and exit the editor to continue.
Optional: Get PCMCIA working
PCMCIA users should now install the sys-apps/pcmciautils package.
root #emerge --ask sys-apps/pcmciautilsSystem information
Root password
Set the root password using the passwd command.
root #passwdThe root Linux account is an all-powerful account, so pick a strong password. Later an additional regular user account will be created for daily operations.
Init and boot configuration
Gentoo (at least when using OpenRC) uses /etc/rc.conf to configure the services, startup, and shutdown of a system. Open up /etc/rc.conf and enjoy all the comments in the file. Review the settings and change where needed.
root #nano -w /etc/rc.confNext, open /etc/conf.d/keymaps to handle keyboard configuration. Edit it to configure and select the right keyboard.
root #nano -w /etc/conf.d/keymapsTake special care with the keymap variable. If the wrong keymap is selected, then weird results will come up when typing on the keyboard.
Finally, edit /etc/conf.d/hwclock to set the clock options. Edit it according to personal preference.
root #nano -w /etc/conf.d/hwclockIf the hardware clock is not using UTC, then it is necessary to set clock="local" in the file. Otherwise the system might show clock skew behavior.
System logger
Some tools are missing from the stage3 archive because several packages provide the same functionality. It is now up to the user to choose which ones to install.
The first tool to decide on has to provide logging facilities for the system. Unix and Linux have an excellent history of logging capabilities - if needed, everything that happens on the system can be logged in log files. This happens through the system logger.
Gentoo offers several system logger utilities. A few of these include:
- app-admin/sysklogd - Offers the traditional set of system logging daemons. The default logging configuration works well out of the box which makes this package a good option for beginners.
- app-admin/syslog-ng - An advanced system logger. Requires additional configuration for anything beyond logging to one big file. More advanced users may choose this package based on it's logging potential; be aware additional configuration is a necessity for any kind of smart logging.
- app-admin/metalog - A highly-configurable system logger.
Others are available through Portage as well - the number of available packages increases on a daily basis.
If sysklogd or syslog-ng are going to be used, it is recommended to install and configure logrotate afterwards as those system loggers don't provide any rotation mechanism for the log files.
systemd provides its own logging facility called the "journal". Installing a separate syslog provider is optional on systems running systemd, and may require additional configuration to have the syslog daemon read messages from the journal.
To install the system logger of choice, emerge it and have it added to the default runlevel using rc-update. The following example installs app-admin/sysklogd:
root #emerge --ask app-admin/sysklogdroot #rc-update add sysklogd defaultOptional: Cron daemon
Next is the cron daemon. Although it is optional and not required for every system, it is wise to install one.
A cron daemon executes scheduled commands. It is very handy if some command needs to be executed regularly (for instance daily, weekly or monthly).
Gentoo offers several possible cron daemons, including sys-process/bcron, sys-process/dcron, sys-process/fcron, and sys-process/cronie. Installing one of them is similar to installing a system logger. The following example uses sys-process/cronie:
root #emerge --ask sys-process/cronieroot #rc-update add cronie defaultIf dcron or fcron are used, an additional initialization command needs to be executed:
root #crontab /etc/crontabOptional: File indexing
In order to index the file system to provide faster file location capabilities, install sys-apps/mlocate.
root #emerge --ask sys-apps/mlocateOptional: Remote access
To be able to access the system remotely after installation, add the sshd init script to the default runlevel:
root #rc-update add sshd defaultIf serial console access is needed (which is possible in case of remote servers), uncomment the serial console section in /etc/inittab:
root #nano -w /etc/inittab# SERIAL CONSOLES s0:12345:respawn:/sbin/agetty 9600 ttyS0 vt100 s1:12345:respawn:/sbin/agetty 9600 ttyS1 vt100
Filesystem tools
Depending on the filesystems used, it is necessary to install the required file system utilities (for checking the filesystem integrity, creating additional file systems etc.). Note that tools for managing ext2, ext3, or ext4 filesystems (sys-fs/e2fsprogs) are already installed as a part of the @system set.
The following table lists the tools to install if a certain filesystem is used:
| Filesystem | Package |
|---|---|
| Ext2, 3, and 4 | sys-fs/e2fsprogs |
| XFS | sys-fs/xfsprogs |
| ReiserFS | sys-fs/reiserfsprogs |
| JFS | sys-fs/jfsutils |
| VFAT (FAT32, ...) | sys-fs/dosfstools |
| Btrfs | sys-fs/btrfs-progs |
For more information on filesystems in Gentoo see the filesystem article.
Networking tools
If there is no need for any additional networking tools, continue immediately with the section on Configuring a bootloader.
Installing a DHCP client
Although optional, the majority of users will find that they need a DHCP client to connect to the DHCP server on their network. Please take this opportunity to install a DHCP client. If this step is forgotten, then the system might not be able to get on the network thus making it impossible to download a DHCP client afterward.
In order for the system to automatically obtain an IP address for one or more network interface(s) using netifrc scripts, it is necessary to install a DHCP client. We recommend the use of net-misc/dhcpcd although many other DHCP clients are available through the Gentoo repository:
root #emerge --ask net-misc/dhcpcdMore information on dhcpcd can be found in the dhcpcd article.
Optional: Installing a PPPoE client
If PPP is used to connect to the internet, install the net-dialup/ppp package:
root #emerge --ask net-dialup/pppOptional: Install wireless networking tools
If the system will be connecting to wireless networks, install the net-wireless/iw package for Open or WEP networks and/or the net-wireless/wpa_supplicant package for WPA or WPA2 networks. iw is also a useful basic diagnostic tool for scanning wireless networks.
root #emerge --ask net-wireless/iw net-wireless/wpa_supplicantNow continue with Configuring the bootloader.
Placeholder for architecture-specific bootloader installation
Rebooting the system
Exit the chrooted environment and unmount all mounted partitions. Then type in that one magical command that initiates the final, true test: reboot.
root #exitcdimage ~#cd
cdimage ~#umount -l /mnt/gentoo/dev{/shm,/pts,}
cdimage ~#umount -R /mnt/gentoo
cdimage ~#rebootDo not forget to remove the bootable CD, otherwise the CD might be booted again instead of the new Gentoo system.
Once rebooted in the freshly installed Gentoo environment, finish up with Finalizing the Gentoo installation.
User administration
Adding a user for daily use
Working as root on a Unix/Linux system is dangerous and should be avoided as much as possible. Therefore it is strongly recommended to add a user for day-to-day use.
The groups the user is member of define what activities the user can perform. The following table lists a number of important groups:
| Group | Description |
|---|---|
| audio | Be able to access the audio devices. |
| cdrom | Be able to directly access optical devices. |
| floppy | Be able to directly access floppy devices. |
| games | Be able to play games. |
| portage | Be able to access portage restricted resources. |
| usb | Be able to access USB devices. |
| video | Be able to access video capturing hardware and doing hardware acceleration. |
| wheel | Be able to use su. |
For instance, to create a user called larry who is member of the wheel, users, and audio groups, log in as root first (only root can create users) and run useradd:
Login:rootPassword: (Enter the root password)
root #useradd -m -G users,wheel,audio -s /bin/bash larry
root #passwd larryPassword: (Enter the password for larry) Re-enter password: (Re-enter the password to verify)
If a user ever needs to perform some task as root, they can use su - to temporarily receive root privileges. Another way is to use the sudo package which is, if correctly configured, very secure.
Disk cleanup
Removing tarballs
With the Gentoo installation finished and the system rebooted, if everything has gone well, we can now remove the downloaded stage3 tarball from the hard disk. Remember that they were downloaded to the / directory.
root #rm /stage3-*.tar.bz2*Where to go from here
Documentation
Not sure where to go from here? There are many paths to explore... Gentoo provides its users with lots of possibilities, and therefore lots of documented (and less documented) features.
Definitely take a look at the next part of the Gentoo Handbook entitled Working with Gentoo which explains how to keep the software up to date, install additional software packages, details on USE flags, the OpenRC init system, etc.
Apart from the handbook, readers should also feel encouraged to explore other corners of the Gentoo wiki to find additional, community-provided documentation. The Gentoo wiki team also offers a Documentation topic overview which lists a selection of wiki articles by category. For instance, it refers to the localization guide to make a system feel more at home (particularly useful for users who speak English as a second language).
Gentoo online
Everyone is of course always welcome on our Gentoo forums or on one of our Gentoo IRC channels.
We also have several mailing lists open to our users.
Enjoy Gentoo!