Podman

Installation

Podman can be installed via podman package in the community repository.

# apk add podman

Running as root

To run podman you'll need to enable the cgroups service, consider enabling cgroups v2.

# rc-update add cgroups

# rc-service cgroups start

You might need to restart your machine for this to work properly.

If you are running on top of Btrfs, consider setting storage driver to btrfs:

$ cat /etc/containers/storage.conf

driver = "btrfs"

If you're running inside a container, change the storage driver to vfs

Running in rootless mode

For rootless support (replace <USER> with your username):

# modprobe tun # echo tun >>/etc/modules # echo <USER>:100000:65536 >/etc/subuid # echo <USER>:100000:65536 >/etc/subgid

Run an example container to verify everything works:

$ podman run --rm hello-world

Shared mount

Containers on linux might require filesystems to be mounted with different propagation than the kernel default of 'private'. If you see a warning:

WARN[0000] "/" is not a shared mount, this could cause issues or missing mounts with rootless containers

you might want to fix this temporarily, for currently running system:

# mount --make-rshared /

and try the command that caused the warning again.

Alternatively, you could use following command:

# findmnt -o PROPAGATION /

which should print:

   PROPAGATION
   shared

For a permanent fix (after a OpenRC PR#526 is released - in newer version than 0.54.2-r1), edit /etc/fstab:

# $EDITOR /etc/fstab

Add shared option to the root partition:

  /dev/sda2 / ext4 rw,relatime,shared 0 1

and after a reboot test it out similarly as above.

Docker compose

Podman provides a drop-in replacement for docker compose. The podman-compose package provides this.

Each time that docker compose is used, a warning will remind that this is using podman under the hood. This warning can be squelched permanently by running:

# touch /etc/containers/nodocker