Podman: Difference between revisions

Latest revision as of 20:41, 26 September 2024

Podman can run rootless containers and be a drop-in replacement for Docker.

Setup

To enable Podman support, add following lines to your system configuration

# Enable common container config files in /etc/containers
virtualisation.containers.enable = true;
virtualisation = {
  podman = {
    enable = true;
    # Create a `docker` alias for podman, to use it as a drop-in replacement
    dockerCompat = true;
    # Required for containers under podman-compose to be able to talk to each other.
    defaultNetwork.settings.dns_enabled = true;
  };
};

users.users.myuser = {
  isNormalUser = true;
  extraGroups = [ "podman" ];
};

Replace myuser with your current user. A reboot or re-login might be required for the permissions to take effect after applying changes.

Tips and tricks

podman-compose

podman-compose is a drop-in replacement for docker-compose

Using podman with ZFS

Rootless can't use ZFS directly but the overlay needs POSIX ACL enabled for the underlying ZFS filesystem, ie., acltype=posixacl

Best to mount a dataset under /var/lib/containers/storage with property acltype=posixacl.

Use Podman within nix-shell

https://gist.github.com/adisbladis/187204cb772800489ee3dac4acdd9947

Note that rootless podman requires newuidmap (from shadow). If you're not on NixOS, this cannot be supplied by the Nix package 'shadow' since setuid/setgid programs are not currently supported by Nix.

Run Podman containers as systemd services

{
  virtualisation.oci-containers.backend = "podman";
  virtualisation.oci-containers.containers = {
    container-name = {
      image = "container-image";
      autoStart = true;
      ports = [ "127.0.0.1:1234:1234" ];
    };
  };
}

@@ Line 1: / Line 1: @@
-== Install podman ==
+[https://podman.io/ Podman] can run rootless containers and be a drop-in replacement for [[Docker]].
-<syntaxHighlight lang="nix">
+== Setup ==
-{ pkgs, ... }:
+To enable Podman support, add following lines to your system configuration<syntaxhighlight lang="nix">
-{
+# Enable common container config files in /etc/containers
-   environment.systemPackages = with pkgs; [ podman runc conmon slirp4netns fuse-overlayfs ];
+virtualisation.containers.enable = true;
-}
+virtualisation = {
-</syntaxHighlight>
+  podman = {
+    enable = true;
+    # Create a `docker` alias for podman, to use it as a drop-in replacement
+    dockerCompat = true;
+    # Required for containers under podman-compose to be able to talk to each other.
+    defaultNetwork.settings.dns_enabled = true;
+  };
+};
+users.users.myuser = {
+   isNormalUser = true;
+  extraGroups = [ "podman" ];
+};
+</syntaxhighlight>Replace <code>myuser</code> with your current user. A reboot or re-login might be required for the permissions to take effect after applying changes.
+== Tips and tricks ==
+=== podman-compose ===
+<code>podman-compose</code> is a drop-in replacement for <code>docker-compose</code>
+=== Using podman with ZFS ===
-== Configure subuid/subgid for your user ==
+Rootless can't use [[ZFS]] directly but the overlay needs POSIX ACL enabled for the underlying ZFS filesystem, ie., <code>acltype=posixacl</code>
-<syntaxHighlight lang="nix">
+Best to mount a dataset under <code>/var/lib/containers/storage</code> with property <code>acltype=posixacl</code>.
-users.users.username.subUidRanges = [{ startUid = 100000; count = 65536; }];
-users.users.username.subGidRanges = [{ startGid = 100000; count = 65536; }];
-</syntaxHighlight>
+=== Use Podman within nix-shell ===
+https://gist.github.com/adisbladis/187204cb772800489ee3dac4acdd9947
-== Create configuration files ==
+Note that rootless podman requires newuidmap (from shadow). If you're not on NixOS, this cannot be supplied by the Nix package 'shadow' since [https://nixos.org/manual/nix/unstable/expressions/derivations.html setuid/setgid programs are not currently supported by Nix].
+=== Run Podman containers as systemd services ===
 <syntaxHighlight lang="nix">
-environment.etc."containers/policy.json" = {
+{
-  mode="0644";
+  virtualisation.oci-containers.backend = "podman";
-   text=''
+   virtualisation.oci-containers.containers = {
-     {
+     container-name = {
-       "default": [
+       image = "container-image";
-        {
+       autoStart = true;
-          "type": "insecureAcceptAnything"
+       ports = [ "127.0.0.1:1234:1234" ];
-        }
+     };
-       ],
+   };
-       "transports":
+}
-        {
+</syntaxHighlight>
-          "docker-daemon":
-            {
-              "": [{"type":"insecureAcceptAnything"}]
-            }
-        }
-     }
-   '';
-};
-environment.etc."containers/registries.conf" = {
+[[Category:Software]]
-  mode="0644";
+[[Category:Server]]
-  text=''
+[[Category:Container]]
-    [registries.search]
-    registries = ['docker.io', 'quay.io']
-  '';
-};
-</syntaxHighlight>