Install Alpine Linux on Encrypted Btrfs partition

alpine-install.md

Alpine Linux Installation on Encrypted Btrfs partition

Setup keymap, hostname, interfaces and network

setup-alpine

When prompted to select the disk for installation, press Ctrl+C to cancel the guided installation process.

Add required packages for installation

apk add cryptsetup e2fsprogs btrfs-progs dosfstools parted mkinitfs

Partitioning

Create a EFI and Luks partition

parted /dev/sdX -a optimal
mklabel gpt
mkpart primany fat32 0% 200M
name 1 esp
set 1 esp on
mkpart primary btrfs 200M 100%
name 2 luks

Encrypt partition with LUKS

cryptsetup luksFormat /dev/sdX2

Unlock the partition

cryptsetup luksOpen /dev/sdX2 luks

Format LUKS partition as Btrfs

mkfs.btrfs /dev/mapper/luks

Create Btrfs subvolumes

mount /dev/mapper/luks /mnt
btrfs sub create /mnt/root
btrfs sub create /mnt/home
btrfs sub create /mnt/var
umount /mnt

Mount subvolumes

mount -o noatime,nodiratime,compress=zstd,space_cache=v2,ssd,subvol=root /dev/mapper/luks /mnt
mkdir -p /mnt/home
mkdir -p /mnt/var
mount -o noatime,nodiratime,compress=zstd,space_cache=v2,ssd,subvol=home /dev/mapper/luks /mnt/home
mount -o noatime,nodiratime,compress=zstd,space_cache=v2,ssd,subvol=var /dev/mapper/luks /mnt/var

Mount EFI partition

mkfs.fat -F32 /dev/sdX1
mkdir -p /mnt/boot
mount -t vfat /dev/sdX1 /mnt/boot

Install the system

setup-disk -m sys /mnt/

Initramfs config

Edit /mnt/etc/mkinitfs/mkinitfs.conf and add cryptsetup to the features. Rebuild initramfs

mkinitfs -c /mnt/etc/mkinitfs/mkinitfs.conf -b /mnt $(ls /mnt/lib/modules/)

CHROOT

Mount necessary partitions

mount -t proc /proc /mnt/proc
mount --rbind /dev /mnt/dev
mount --make-rslave /mnt/dev
mount --rbind /sys /mnt/sys

Chroot on installation directory

chroot /mnt
source /etc/profile
export PS1="(chroot) $PS1"

Bootloader Configuration

Install necessary packages

apk add grub grub-efi efibootmgr

Edit /etc/default/grub and modify GRUB_CMDLINE_LINUX_DEFAULT

GRUB_CMDLINE_LINUX_DEFAULT="... cryptroot=UUID=<UUID of /dev/sdX2> cryptdm=luks rootflags=subvol=root rootfstype=btrfs"

Install grub

grub-install --target=x86_64-efi --efi-directory=/boot
grub-mkconfig -o /boot/grub/grub.cfg