To install Gentoo this guide will be using the Alpine Extended Iso. It provides all of the necessary utilities for bootstrapping Gentoo and is overal pleasant to work with. Make sure to boot with Secureboot in setup mode or to already have keys ready to deploy.

After booting the Alpine Linux extended ISO, partition the disks. For this action internet is required since `zfs`, `sgdisk` and various other necessary packages are not included on the extended ISO, therefore they need to be obtained from the alpine package repository.

To set it up `setup-interfaces` and `setup-apkrepos` will be used.

``` shell
root # setup-interfaces -ar
root # setup-apkrepos -c1
```

> To use Wi-Fi simply run `setup-interfaces -r` and select `wlan0` or similar.

A few packages will have to be installed first,

``` shell
root # apk add zfs lsblk sgdisk wipefs dosfstools
```

and load the ZFS kernel module

``` shell
root # modprobe zfs
```

Wipe the existing disk partitions

``` shell
root # zpool labelclear -f /dev/<disk>
root # wipefs -a /dev/<disk>
root # sgdisk --zap-all /dev/<disk>
```

Create on the disk an `EFI system` partition (ESP) and a `Linux filesystem` partition

``` shell
root # sgdisk -n 1:1m:+512m -t 1:ef00 /dev/<disk>
root # sgdisk -n 2:0:-10m -t 2:8300 /dev/<disk>
```

Reload the device nodes

``` shell
root # mdev -s
```

Then, format the ESP with a FAT32 filesystem

``` shell
root # mkfs.fat -F 32 -n esp /dev/<disk>1
```

## ZFS pool creation

The ZFS system pool is going to be encrypted. First generate an encryption key and save it temporarily to the file `/tmp/rpool.key` with:

``` shell
root # cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 20 | head -n 1 > /tmp/rpool.key && cat /tmp/rpool.key
```

> Later on in the guide `zlevis` will be used for automatic decryption, so this key only has to be entered a few times. However, if any changes are made to the bios or secureboot then this key will be needed again, so make sure to save it.

Create the system pool:

``` shell
root # zpool create -f \
        -o ashift=12 \
        -O compression=lz4 \
        -O acltype=posix \ 
        -O xattr=sa \
        -O dnodesize=auto \
        -O encryption=on \
        -O keyformat=passphrase \
        -O keylocation=prompt \
        -m none \
        rpool /dev/<disk>2
```

Then create the system datasets:

``` shell
root # zfs create -o mountpoint=none rpool/root
root # zfs create -o mountpoint=legacy -o quota=48g rpool/root/gentoo
root # zfs create -o mountpoint=legacy -o quota=32g rpool/root/gentoo/var
root # zfs create -o mountpoint=/home -o atime=off -o setuid=off -o devices=off -o quota=<home-quota> rpool/home
```

> Setting the `<home-quota>` depends on the total size of the pool, generally try to reserve some empty space in the pool.