Gentoo

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Installation

The Gentoo Handbook is usually a very good guide through the whole installation process. In short:

Download a bootable CD image:

 http://distfiles.gentoo.org/releases/x86/autobuilds/current-iso/

Verify signature:

gpg --keyserver subkeys.pgp.net --recv-keys 96D8BF6D 2D182910 17072058
 
gpg --verify install-x86-minimal-*.iso.DIGESTS.asc
sha1sum -c   install-x86-minimal-*.iso.DIGESTS

Setup networking:

ifconfig eth0 10.0.0.30 netmask 255.255.255.0
route add default gw 10.0.0.1
echo "nameserver 10.0.0.1" > /etc/resolv.conf

Enable ssh and set a password - that way we'll be able to install the system remotely:

/etc/init.d/sshd start
passwd

While we're at it, set the system time:

ntpdate pool.ntp.org

Continue with the actual setup:

parted                   # Create partitions
mkfs.ext4 /dev/sda1      # Create filesystem
mkswap    /dev/sda2      # Initialize swapspace
mount -t ext4 /dev/sda1 /mnt/gentoo
swapon /dev/sda2

Download stage tarball and portage snapshot:

cd /mnt/gentoo
LATEST=`wget -q http://distfiles.gentoo.org/releases/x86/autobuilds/latest-stage3-i686.txt -O - | tail -1`
wget http://distfiles.gentoo.org/releases/x86/autobuilds/$LATEST{,.DIGESTS.asc,.DIGESTS}
wget http://distfiles.gentoo.org/releases/snapshots/current/portage-latest.tar.xz{,.gpgsig,.md5sum}
 
md5sum -c    stage3-*.tar.bz2.DIGESTS
gpg --verify stage3-*.tar.bz2.DIGESTS.asc
 
md5sum -c    portage-latest.tar.xz.md5sum
gpg --verify portage-latest.tar.xz.gpgsig

Unpack:

tar -xjpvf stage3-*.tar.bz2
xz -dc portage-latest.tar.xz | tar -C /mnt/gentoo/usr -xvf -

Check make.conf, as we'll build a few things afterwards:

$ cat /mnt/gentoo/etc/make.conf
CFLAGS="-O2 -march=i686 -pipe"
CXXFLAGS="${CFLAGS}"
CHOST="i686-pc-linux-gnu"
MAKEOPTS="-j4"
 
$ mirrorselect -i -o >> /mnt/gentoo/etc/make.conf

Chroot into our new system:

mount -t proc none /mnt/gentoo/proc
mount --rbind /dev /mnt/gentoo/dev
chroot /mnt/gentoo /bin/bash
env-update
source /etc/profile
export PS1="(chroot) $PS1"

Set root password:

passwd

Configure locale:

$ grep ^[a-z] /etc/locale.gen
en_US.UTF-8 UTF-8
$ locale-gen

Configure timezone:

cp /usr/share/zoneinfo/PST8PDT /etc/localtime

Update portage tree, select system profile

$ emerge --sync
$ eselect profile list
Available profile symlink targets:
[1]   default/linux/x86/10.0 *
[2]   default/linux/x86/10.0/selinux
[3]   default/linux/x86/10.0/desktop
[4]   default/linux/x86/10.0/desktop/gnome
[5]   default/linux/x86/10.0/desktop/kde
[6]   default/linux/x86/10.0/developer
[7]   default/linux/x86/10.0/server
[8]   hardened/linux/x86
[9]   hardened/linux/x86/selinux

$ eselect profile set 1

Emerge and activate a few programs:

emerge syslog-ng vixie-cron bash-completion less vim [dhcpcd, xfsprogs, reiserfsprogs, jfsutils]
rc-update add syslog-ng default
rc-update add vixie-cron default
rc-update add sshd default

Oh, to actually enable bash-completion, this hack might be helpful:

cd /etc/bash_completion.d/
  for c in /usr/share/bash-completion/[a-z]*; do ln -s $c `basename $c`
done


Configure network:

$ grep . /etc/conf.d/hostname /etc/conf.d/net
/etc/conf.d/hostname:hostname="foobar"
/etc/conf.d/net:dns_domain_lo="example.com"
/etc/conf.d/net:nis_domain_lo="example.com"
/etc/conf.d/net:#config_eth0="dhcp"
/etc/conf.d/net:config_eth0="10.0.0.30  netmask 255.255.255.0 brd 10.0.0.255"
/etc/conf.d/net:routes_eth0="default via 10.0.0.1"
 
$ cd /etc/init.d
$ ln -s net.lo net.eth0
$ rc-update add net.eth0 default

Configure kernel, manually:

emerge gentoo-sources

cd /usr/src/linux
make menuconfig
[...]
 
make && make modules_install
cp System.map arch/x86/boot/bzImage /boot/

Configure kernel, with genkernel, check modules to be loaded:

$ emerge genkernel
$ genkernel all
 
$ grep ^m /etc/conf.d/modules
modules="3c59x"

Configure fstab:

$ grep ^/ /etc/fstab 
/dev/sda1     /       ext4   noatime                       0 1
/dev/sda2     none    swap   sw                            0 0
tmpfs         /tmp    tmpfs  nodev,nosuid,noexec,mode=1777 0 0
proc          /proc   proc   nodev,nosuid,noexec,hidepid=2 0 0

Install bootloader:

$ emerge grub
$ cat /boot/grub/grub.conf 
default 0
timeout 30
# splashimage=(hd0,0)/boot/grub/splash.xpm.gz
 
title Gentoo Linux
root (hd0,0)
kernel /boot/bzImage root=/dev/sda1
# initrd /boot/initramfs
$ grep -v rootfs /proc/mounts > /etc/mtab
$ grub-install --no-floppy /dev/sda

If this last step fails, try manually:

$ grub --no-floppy
> root (hd0,0)
> setup (hd0)
> quit

There's also /etc/rc.conf, /etc/conf.d/keymaps and /etc/conf.d/hwclock to setup, but this can be done later as well.

Reboot into the newly installed system:

exit
cd /
umount -l /mnt/gentoo/dev{/shm,/pts,}
umount -l /mnt/gentoo{/boot,/proc,}
reboot

When rebooting was successful and the new system is up & running, remove the tarballs:

rm /stage3-*.tar.bz2* /portage-latest.tar*

Postinstall

distcc, ccache

$ cat /etc/make.conf
[...]
MAKEOPTS="-j6"
FEATURES="ccache distcc"                    ← Order matters!
CCACHE_DIR="/var/tmp/ccache"
CCACHE_SIZE="2G"
# CC="gcc"                                  ← Can help if the distcc nodes are
# CXX="c++"                                   using different compiler versions

See distcc for details.

cachefilesd

Use cachefilesd to speed up NFS mounts by caching contents:

emerge cachefilesd
rc-update add cachefilesd default

Now NFS filesystems can be mounted with fsc and will be cached to /var/cache/fscache/

Updating

Update the portage tree, this might take a few minutes:

emerge --sync

Update a specific package, e.g. curl:

emerge --update --deep --newuse --ask curl

Update the whole system, this might take even longer:

  • with deep dependency checking
  • including build dependencies
  • check for newly modified USE flags
  • ask before doing anything
emerge --update --deep --newuse --ask --with-bdeps=y world

Update configuration files in /etc after world has been updated:

etc-update

Removing orphaned dependencies:

emerge --depclean --ask
emerge gentoolkit && revdep-rebuild

Kernel Update

Before updating the kernel, make sure the "symlink" flag is set, so that the /usr/src/linux symlink gets updated too:

$ grep symlink /etc/portage/make.conf
USE="symlink"

Update the kernel sources:

emerge --update sys-kernel/hardened-sources      # Or /vanilla-sources or /gentoo-sources, etc...

We can build the kernel as a mere user:

cd /usr/src/linux
DIR=/var/tmp/linux
mkdir $DIR
sudo zcat /proc/config.gz > $DIR/.config
make     O=$DIR oldconfig
make -j4 O=$DIR

Install the kernel as root:

sudo make O=$DIR modules_install

cd $DIR
V=$(awk '/Kernel Configuration/ {print $3}' .config)       # In this case, "3.7.0-hardened"

sudo cp arch/x86/boot/bzImage /boot/bzImage-$V
sudo cp System.map /boot/System.map-$V
sudo cp .config /boot/config-$V

Be sure to update the bootloader as well!

Upgrading

There's not really an upgrade path, but to follow the #Updating instructions above. Sometimes a new release provides a new profile, which can be selected via eselect profile.

Portage

make.conf

PORTDIR=/usr/portage
PORTAGE_TMPDIR=/var/tmp
DISTDIR=/usr/portage/distfiles           # Fixme: is there a way to relocate /usr/portage/metadata?
# NOCOLOR=true

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