Install Gentoo on BtrFS subvolumes + UEFI

00-gentoo-installation-partitioning.bash

#!/usr/bin/env bash

# WARNING!!
# This will obliterate all the data in your partition!! (not actually true, but act as if it was)
# Do NOT execute this script if you don't fully understand it!

# a few vars
amount_of_swap=$( free --si -g | grep Mem: | gawk '{ print $2 + 1}' )

# create directories
mkdir -p /mnt/gentoo

# create partitions
# I would add your amount of RAM + something (1 GB maybe?) to the swap partition (#3) instead of 9.
sgdisk -Z /dev/vda
sgdisk -o /dev/vda
sgdisk -n 1::+1024M -t 1:ef02 /dev/vda
sgdisk -n 2::+1G -t 2:8300 /dev/vda
sgdisk -n 3::+${amount_of_swap}G -t 3:8200 /dev/vda
sgdisk -n 4:: -t 4:8300 /dev/vda

# create filesystems
mkfs -t vfat -F 32 /dev/vda1
mkfs -t btrfs -L boot /dev/vda2
mkfs -t btrfs -L btrfsroot /dev/vda4
mkswap /dev/vda3

# mount
## root
mount /dev/vda4 /mnt/gentoo
mkdir -p /mnt/gentoo/boot

## boot
mount /dev/vda2 /mnt/gentoo/boot
mkdir -p /mnt/gentoo/boot/efi


# create subvols
cd /mnt/gentoo
btrfs subvol create root
btrfs subvol create home
btrfs subvol create srv
btrfs subvol create var

# unmount
cd ..
umount -l gentoo

01-gentoo-installation.bash

#!/usr/bin/env bash
# This is a recipe; not a script. You should try to run it chunk by chunck.
# The shebang is only for syntax highlighting

# Chroot
## Please, run this right after running script 00
mount -o defaults,relatime,compress=lzo,autodefrag,subvol=root /dev/vda4 /mnt/gentoo

## create dirs for mounts
cd /mnt/gentoo
mkdir srv home root var boot

## mount
mount -o defaults,relatime,compress=lzo,autodefrag,subvol=home /dev/vda4 /mnt/gentoo/home
mount -o defaults,relatime,compress=lzo,autodefrag,subvol=srv /dev/vda4 /mnt/gentoo/srv
mount -o defaults,relatime,compress=lzo,autodefrag,subvol=var /dev/vda4 /mnt/gentoo/var
mount -o defaults,relatime /dev/vda2 /mnt/gentoo/boot

### efi partition
mount -o defaults,noatime /dev/vda1 /mnt/gentoo/boot/efi

## get gentoo stage3
curl -LO https://bouncer.gentoo.org/fetch/root/all/releases/amd64/autobuilds/20211121T170545Z/stage3-amd64-nomultilib-systemd-20211121T170545Z.tar.xz

## uncompress
tar -xapf stage3-amd64-nomultilib-systemd-20211121T170545Z.tar.xz
rm -f $_

## mount proc, sys and dev
mount --types proc /proc /mnt/gentoo/proc
mount --rbind /sys /mnt/gentoo/sys
mount --make-rslave /mnt/gentoo/sys
mount --rbind /dev /mnt/gentoo/dev
mount --make-rslave /mnt/gentoo/dev

## activate swap
swapon /dev/vda3

## get dns
cp -u /etc/resolv.conf /mnt/gentoo/etc/

## chroot
env -i HOME=/root TERM=$TERM chroot . bash -l

## environment
env-update
source /etc/profile
export PS1="(chroot) $PS1"

# emerge
## sync repo first
emaint -A sync

## update portage
emerge --oneshot portage

# portage (git)
# ref: https://wiki.gentoo.org/wiki/Portage_with_Git

## install dependencies for emerge with git
emerge -Dju app-eselect/eselect-repository dev-vcs/git

## setup portage to use git instead of rsync
eselect repository remove gentoo
eselect repository add gentoo git https://github.com/gentoo-mirror/gentoo.git
rm -r /var/db/repos/gentoo

## sync
emaint sync -r gentoo

# Setup
## fstab
cat << 'EOF' > /etc/fstab
# <fs>      <mountpoint>    <type>  <opts>                                              <dump/pass>
shm         /dev/shm        tmpfs   nodev,nosuid,noexec                                 0 0
/dev/vda4   /               btrfs   rw,relatime,compress=zstd:1,autodefrag,subvol=root   0 0
/dev/vda4   /home           btrfs   rw,relatime,compress=zstd:1,autodefrag,subvol=home   0 0
/dev/vda4   /srv            btrfs   rw,relatime,compress=zstd:1,autodefrag,subvol=srv    0 0
/dev/vda4   /var            btrfs   rw,relatime,compress=zstd:1,autodefrag,subvol=var    0 0
/dev/vda3   none            swap    sw                                                  0 0
/dev/vda2   /boot           btrfs   rw,relatime                                          1 2
/dev/vda1   /boot/efi       vfat    umask=0077,shortname=winnt                          0 2

EOF

## local time in MX
ln -sf /usr/share/zoneinfo/Etc/UTC /etc/localtime

## add cpu flags
emerge app-portage/cpuid2cpuflags
cpu_flags=$( cpuid2cpuflags | cut -d ' ' -f '2-' )

## append to my make.conf
use_remove='-accessibility -altivec -apache2 -aqua -big-endian -bindist -boundschecking -bsf -canna -clamav -connman -coreaudio -custom-cflags -debug -dedicated -emacs -handbook -ibm -infiniband -iwmmxt -kde -kontact -libav -libedit -libressl -libsamplerate -mono -mule -neon -oci8 -oci8-instant-client -oracle -oss -pch -pcmcia -plasma -qmail-spp -qt4 -qt5 -static -syslog -sysvipc -tcpd -xemacs -yahoo -zsh-completion'
use_add='symlink unicode vim-syntax'
make_opts="-j$(( $( nproc ) + 1 ))"

cat << EOF > /etc/portage/make.conf
CFLAGS="-mtune=native -O2 -pipe"
CXXFLAGS=\${CFLAGS}
CHOST="x86_64-pc-linux-gnu"
CPU_FLAGS_X86="${cpu_flags}"

GRUB_PLATFORMS="efi-64"

# enable this if you like living on the edge
#ACCEPT_KEYWORDS="~amd64"
MAKEOPTS="${make_opts}"

ADD="${use_add}"
REMOVE="${use_remove}"
USE="\$REMOVE \$ADD"

# Portage Opts
FEATURES="parallel-fetch parallel-install ebuild-locks"
EMERGE_DEFAULT_OPTS="--with-bdeps=y"
AUTOCLEAN="yes"
EOF

## set profiles
eselect profile set default/linux/amd64/17.1/no-multilib/systemd/merged-usr

## update everything and cleanup
emerge -DNju @world
emerge -c

## configure os-prober to mount grub
cat << 'EOF' > /etc/portage/package.use/os-prober
>=sys-boot/grub-2.06-r7 mount

EOF

## install useful apps
emerge -DNju vim bash-completion btrfs-progs
emerge -DNju app-portage/eix app-portage/gentoolkit sys-process/htop sys-process/lsof sys-boot/os-prober

## install vanilla sources and genkernel-next
mkdir -p /etc/portage/package.license

cat << 'EOF' > /etc/portage/package.license/linux-firmware
sys-kernel/linux-firmware linux-fw-redistributable no-source-code

EOF

emerge -DNju genkernel sys-kernel/gentoo-sources sys-kernel/linux-firmware

## Remember to enable:
## 	 * all virtio devices; at least: virtio_pci and virtio_blk
##	 * btrfs support
genkernel --menuconfig --btrfs --virtio all

# Configure real root and stuff
# Do not forget to append systemd to the kernel command line: GRUB_CMDLINE_LINUX="real_init=/lib/systemd/systemd quiet"
vim /etc/default/grub

## install grub
grub-install --target=x86_64-efi --efi-directory=/boot/efi

# update grub
grub-mkconfig -o /boot/grub/grub.cfg

# systemd
## Setup machine ID to activate journaling
systemd-machine-id-setup

## DHCP
cat << 'EOF' > /etc/systemd/network/20-default.network
[Match]
Name = enp*

[Network]
DHCP = yes

EOF

systemctl enable systemd-networkd.socket

# set root password
passwd

# reboot (and pray, think wishfully, cross your fingers or whatever you do to influence reality... not!)
reboot

# after reboot
## set hostname
# hostnamectl set-hostname my.example.tld

## set locale (after reboot)
# localectl set-locale LANG=<LOCALE>

## set time and date
# timedatectl --help

well done, super helpful

Glad to know it was useful! :D

This seems to be missing information regarding EFI. I don't see you mounting your EFI partition at any point. I'm not a noob, but I'm not an expert, but /dev/sda1 should be mounted on the efi directory under /boot BEFORE you can install grub. Unless I'm overlooking something?

EDIT: Otherwise very helpful, Thank you for this. Helped since I know what I need to do, just not always the order or specific commands by memory and I don't always want to dig through the Gentoo Handbook.

@oicydwa you're correct! I overlooked that part. Thank you for pointing it out. :D

I'll see if I can work on it during the weekend. If you can give it a try and figure it out, please, report it back so we can improve this one. :)

I'll see if I can work on it during the weekend. If you can give it a try and figure it out, please, report it back so we can improve this one. :)

Really all that's needed is to mount (according to your example) /dev/sda1 (the efi partition) to /boot/efi.
So basically insert below anytime before grub-install:

mkdir /boot/efi
mount /dev/sda1 /boot/efi

Or if before chroot:

mkdir /mnt/gentoo/boot/efi
mount /dev/sda1 /mnt/gentoo/boot/efi

@oicydwa it took more than that. Had to add something to make.conf and the grub install command changes.

OK, updated at Thu Nov 25, 2021. It works at the time of update! ;D

Fixed fstab's /boot/efi entry.

Finished updating it.

Added:

• portage using git (much faster syncs and as many as you like during the day)
• some random fixes.
• relatime where possible.
• merged-usr.