documentation/docs/alpine-server-setup/installation.md

Installation

To install the Alpine Linux distribution on the system, the datasets of the system pool and the EFI partitions have to be mounted to the main system.

First import and decrypt the system pool

# zpool import -N -R /mnt tank
# zfs load-key -L file:///tmp/tank.key tank

Mount the datasets in the system pool and decrypt the home dataset

# zfs mount tank/root/alpine
# zfs mount tank/home
# zfs mount tank/var

Mount the ESP

# mkdir /mnt/esp
# mount /dev/md/esp /mnt/esp -t vfat

Then install Alpine Linux

# setup-disk -m sys /mnt

This will also add grub as bootloader which will be replaced but for now it will reside on the ESP.

To have a functional chroot into the system, bind the system process directories

# for i in dev proc sys run; do
> mount --rbind --make-rslave /$i /mnt/$i
> done
# chroot /mnt

The other setup scripts can be used to configure key aspects of the system. Besides that a few necessary services have to be activated.

# setup-hostname <hostname>
# setup-keymap us us-euro
# setup-timezone -i <area>/<subarea>
# setup-ntp openntpd
# setup-sshd -c dropbear
# rc-update add acpid default
# rc-update add seedrng boot
# rm -rf /var/tmp
# ln -s /tmp /var/tmp
# passwd root

The root password does not really matter because it is going to be locked after a user has been created.

Set the hwclock to use UTC in /etc/conf.d/hwclock and disable writing the time to hardware. Running a NTP negates its usability.

clock="UTC"
clock_hctosys="NO"
clock_systohc="NO"

Configure the ESP raid array to mount

# modprobe raid1
# echo raid1 >> /etc/modules-load.d/raid1.conf
# mdadm --detail --scan >> /etc/mdadm.conf
# rc-update add mdadm boot
# rc-update add mdadm-raid boot

Configure ZFS to mount

rc-update add zfs-import sysinit
rc-update add zfs-mount sysinit

Edit /etc/fstab for correct mounts:

/dev/md/esp    /esp        vfat    defaults,nodev,nosuid,noexec                            0 2
tmpfs          /tmp        tmpfs   rw,size=4G,nr_inodes=5k,nodev,nosuid,noexec,mode=1777   0 0
proc           /proc       proc    nodev,nosuid,noexec,hidepid=2                           0 0

By default, Alpine Linux uses mkinitfs to create an initial ram filesystem, although it is minimal that also means that it lacks some functionality which is needed for a proper setup. Because of this mkinitfs and grub-efi will be replaced with booster and secureboot-hook.

# apk add booster secureboot-hook sbctl
# apk del mkinitfs grub-efi

To configure booster edit /etc/booster.yaml:

enable_zfs: true
busybox: false
modules: vfat,nls_cp437,nls_iso8859_1

The most important step is the creation of a UKI using secureboot-hook which also automatically signs them. First the hook itself will have to be tweaked to use booster instead of mkinitfs, edit /etc/kernel-hooks.d/50-secureboot.hook and change the line:

/sbin/mkinitfs -o "$tmpdir"/initramfs "$NEW_VERSION-$FLAVOR"

to:

/usr/bin/booster build "$tmpdir"/initramfs --kernel-version "$NEW_VERSION-$FLAVOR"

and configure /etc/kernel-hooks.d/secureboot.conf for cmdline and secureboot.

cmdline="rw zfs=tank/root/alpine quiet splash"

signing_cert="/usr/share/secureboot/keys/db/db.pem"
signing_key="/usr/share/secureboot/keys/db/db.key"

output_dir="/esp/efi/linux"
output_name="alpine-linux-{flavor}.efi"

Use sbctl to create secureboot keys and sign them.

# sbctl create-keys
# sbctl enroll-keys

Whilst enrolling the keys it might be necessary to add the --microsoft flag if you are unable to use custom keys.

Set the cache-file of the ZFS pool

# zpool set cachefile=/etc/zfs/zpool.cache tank

Now to see if everything went successfully, run:

# apk fix kernel-hooks

and it should give no warnings if done properly.

As discussed earlier grub will be replaced, install gummiboot as a bootloader.

# apk add gummiboot
# mkdir /esp/loader
# mkdir /esp/efi/boot
# cp /usr/lib/gummiboot/gummibootx64.efi /esp/efi/boot/bootx64.efi

Sign the bootloader with sbctl

# sbctl sign -s /esp/efi/boot/bootx64.efi

and also remove some remnants of grub.

# rm -rf /boot/grub
# rm -rf /etc/default
# cd /boot && unlink boot && cd ..

gummiboot can be configured with the file /esp/loader/loader.conf with which the timeout and the default OS can be specified.

default alpine-linux-lts.efi
timeout 2
editor no

Here, there should be lines explaining the setup of automatic decryption with TPM using Clevis. Which is still in development...

Now exit the chroot and you should be able to reboot into a working Alpine system.

# exit
# umount -lf /mnt
# zpool export tank
# reboot