Assumtions

System is Debian version 11.1 Bullseye
Use bit older version of docker which comes from Debian, not one which is docker project provides itself.
Host has 2 disks
- /dev/sda for OS itself
- /dev/sdb is dedicated for ZFS storage used by docker Nothing stops you to run Debian with Root-on-ZFS and build ZFS only system. It just pain to install at this moment. If you run Ubuntu than you are lucky, go for it.

Steps

Install Debian on /dev/sda
edit /etc/apt/sources.lst and add “contrib and non-free” to the list
```
deb http://deb.debian.org/debian/ bullseye main contrib non-free
```

#apt update
#apt install zfs-dkms docker.io

Create ZFS pool and set properties for root dataset

 #/sbin/modprobe zfs
 #zpool create storage /dev/sdb
 #zpool status
   pool: storage
  state: ONLINE
 config:

 	NAME        STATE     READ WRITE CKSUM
 	storage     ONLINE       0     0     0
 	  sdb       ONLINE       0     0     0

  errors: No known data errors
 #zfs set compression=zstd-3 atime=off storage
 #zfs create -o mountpoint=/var/lib/docker storage/docker

Stop docker

  #systemctl stop docker.socket docker.service

Remove docker storage folder - it will destroy all docker/images/volumes in the system
```
   #rm -rf /var/lib/docker
```

Create docker dataset mounted to /var/lib/docker

   #zfs create -o mountpoint=/var/lib/docker storage/docker

Configure Docker to use zfs. Edit /etc/docker/daemon.json and set the storage-driver to zfs. If the file was empty before, it should now look like this:
```
 {
   "storage-driver": "zfs"
 }
```

Check that docker is using ZFS for storage

# docker info | grep Storage
Storage Driver: zfs

Done

Deploying generic docker hosting on Debian Bullseye with ZFS backend

Assumtions

Steps