Podman: Difference between revisions

Latest revision as of 19:47, 24 August 2024

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

@@ Line 1: / Line 1: @@
 == Installation ==
-The Podman package is from the alpine version 3.14 on in the 'community' repository.
+Podman can be installed via {{Pkg|podman}} package in the community repository.
-  apk add podman
+{{Cmd|# apk add podman}}
-For rootless support:
+=== Running as root ===
-  apk add fuse-overlayfs shadow slirp4netns
+To run podman you'll need to enable the <code>cgroups</code> service, consider enabling [[OpenRC#cgroups v2|cgroups v2]].
-  modprobe tun
-  usermod --add-subuids 100000-165535 <user>
-  usermod --add-subgids 100000-165535 <user>
-  podman system migrate
-Run an example container to verify everything works
+{{Cmd|# rc-update add cgroups}}
+{{Cmd|# rc-service cgroups start}}
-  podman run --rm hello-world
+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 <code>btrfs</code>:
+{{Cmd|$ cat /etc/containers/storage.conf | grep 'driver ='}}
+ driver = "btrfs"
+If you're running inside a container, change the storage driver to <code>vfs</code>
+=== Running in rootless mode ===
+For rootless support (replace <USER> with your username):
+{{Cmd|# modprobe tun
+&#35; echo tun >>/etc/modules
+&#35; echo <USER>:100000:65536 >/etc/subuid
+&#35; echo <USER>:100000:65536 >/etc/subgid}}
+Run an example container to verify everything works:
+{{Cmd|$ 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:
+{{Cmd|# mount --make-rshared /}}
+and try the command that caused the warning again.
+Alternatively, you could use following command:
+{{Cmd|# findmnt -o PROPAGATION /}}
+which should print:
+    PROPAGATION
+    shared
+For a permanent fix (after a [https://github.com/OpenRC/openrc/pull/526 OpenRC PR#526] is released - in newer version than 0.54.2-r1), edit {{path|/etc/fstab}}:
+   {{cmd|# $EDITOR /etc/fstab}}
+Add <code>shared</code> 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 {{Pkg|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:
+{{cmd|# touch /etc/containers/nodocker}}
+[[Category:Virtualization]]