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

# Provisioning

After flasing the Alpine Linux extended ISO, partition a disk. For this action internet is required since `gptfdisk` is not included on the extended ISO, therefore it needs to be obtained from the repository.

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

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

A few packages will have to be installed first:

```
# apk add cryptsetup lsblk btrfs-progs gptfdisk dosfstools acpid
```

The drive should be partitioned using `gdisk` (or `cfdisk`). It should have at least two partitions with one `EFI System` partition and one `Linux filesystem` partition and look something like this:

| Number of partition | Size | Type |
|:-----:|:-----:|:-----:|
| 1     |  512 MB or more | EFI System        |
| 2     |  Rest of the drive | Linux filesystem  |

Then to create the filesystem on the efi partition.

```
# mkfs.fat -F 32 -n efi /dev/<disk>1
```

The main partition of the system is going to be encrypted using `cryptsetup`. First generate a key that will be used to encrypt the device and save it temporarily to the file `/tmp/crypt-key.txt` with:

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

Later on in the guide `clevis` 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 write it down.

Then format the partition using `cryptsetup`:

```
# cryptsetup luksFormat /dev/<disk>2 --type luks2  --cipher aes-xts-plain64 --hash sha512 --iter-time 4000 --key-size 512 --pbkdf argon2id --verify-passphrase
[Enter the generated key]
# cryptsetup open --type luks /dev/<disk>2 luks
```

Now to create a btrfs filesystem on the main partition use:

```
# mkfs.btrfs -L main -n 32k /dev/mapper/luks
```

with `-n` the `nodesize`, larger nodesize gives better packing and less fragmentation at the cost of more expensive memory operations while updating metadata blocks. The default is 16k.

The main partition needs to be mounted.

```
# mount /dev/mapper/luks /mnt -t btrfs
```

To create the necessary subvolumes in the main volume:

```
for i in root home var nix; do
> btrfs subvolume create /mnt/@$i
> done
```

Unmount the main partition. 

```
# umount -lf /mnt
```