Merge pull request #123841 from hercules-ci/podman-socket

nixos/podman: Add docker socket support

4 files changed, 164 insertions, 1 deletions

diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index e51c833a01ca..c45f3268b975 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -1113,6 +1113,7 @@
   ./virtualisation/openvswitch.nix
   ./virtualisation/parallels-guest.nix
   ./virtualisation/podman.nix
+  ./virtualisation/podman-network-socket-ghostunnel.nix
   ./virtualisation/qemu-guest-agent.nix
   ./virtualisation/railcar.nix
   ./virtualisation/spice-usb-redirection.nix
diff --git a/nixos/modules/virtualisation/podman-network-socket-ghostunnel.nix b/nixos/modules/virtualisation/podman-network-socket-ghostunnel.nix
new file mode 100644
index 000000000000..1f1ada7f0891
--- /dev/null
+++ b/nixos/modules/virtualisation/podman-network-socket-ghostunnel.nix
@@ -0,0 +1,34 @@
+{ config, lib, pkg, ... }:
+let
+  inherit (lib)
+    mkOption
+    types
+    ;
+
+  cfg = config.virtualisation.podman.networkSocket;
+
+in
+{
+  options.virtualisation.podman.networkSocket = {
+    server = mkOption {
+      type = types.enum [ "ghostunnel" ];
+    };
+  };
+
+  config = {
+
+    services.ghostunnel = lib.mkIf (cfg.enable && cfg.server == "ghostunnel") {
+      enable = true;
+      servers."podman-socket" = {
+        inherit (cfg.tls) cert key cacert;
+        listen = "${cfg.listenAddress}:${toString cfg.port}";
+        target = "unix:/run/podman/podman.sock";
+        allowAll = lib.mkDefault true;
+      };
+    };
+    systemd.services.ghostunnel-server-podman-socket.serviceConfig.SupplementaryGroups = ["podman"];
+
+  };
+
+  meta.maintainers = lib.teams.podman.members ++ [ lib.maintainers.roberth ];
+}
diff --git a/nixos/modules/virtualisation/podman-network-socket.nix b/nixos/modules/virtualisation/podman-network-socket.nix
new file mode 100644
index 000000000000..1429164630b3
--- /dev/null
+++ b/nixos/modules/virtualisation/podman-network-socket.nix
@@ -0,0 +1,91 @@
+{ config, lib, pkg, ... }:
+let
+  inherit (lib)
+    mkOption
+    types
+    ;
+
+  cfg = config.virtualisation.podman.networkSocket;
+
+in
+{
+  options.virtualisation.podman.networkSocket = {
+    enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Make the Podman and Docker compatibility API available over the network
+        with TLS client certificate authentication.
+
+        This allows Docker clients to connect with the equivalents of the Docker
+        CLI <code>-H</code> and <code>--tls*</code> family of options.
+
+        For certificate setup, see https://docs.docker.com/engine/security/protect-access/
+
+        This option is independent of <xref linkend="opt-virtualisation.podman.dockerSocket.enable"/>.
+      '';
+    };
+
+    server = mkOption {
+      type = types.enum [];
+      description = ''
+        Choice of TLS proxy server.
+      '';
+      example = "ghostunnel";
+    };
+
+    openFirewall = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Whether to open the port in the firewall.
+      '';
+    };
+
+    tls.cacert = mkOption {
+      type = types.path;
+      description = ''
+        Path to CA certificate to use for client authentication.
+      '';
+    };
+
+    tls.cert = mkOption {
+      type = types.path;
+      description = ''
+        Path to certificate describing the server.
+      '';
+    };
+
+    tls.key = mkOption {
+      type = types.path;
+      description = ''
+        Path to the private key corresponding to the server certificate.
+
+        Use a string for this setting. Otherwise it will be copied to the Nix
+        store first, where it is readable by any system process.
+      '';
+    };
+
+    port = mkOption {
+      type = types.port;
+      default = 2376;
+      description = ''
+        TCP port number for receiving TLS connections.
+      '';
+    };
+    listenAddress = mkOption {
+      type = types.str;
+      default = "0.0.0.0";
+      description = ''
+        Interface address for receiving TLS connections.
+      '';
+    };
+  };
+
+  config = {
+    networking.firewall.allowedTCPPorts =
+      lib.optional (cfg.enable && cfg.openFirewall) cfg.port;
+  };
+
+  meta.maintainers = lib.teams.podman.members ++ [ lib.maintainers.roberth ];
+}
diff --git a/nixos/modules/virtualisation/podman.nix b/nixos/modules/virtualisation/podman.nix
index d6421d488b8b..01ff84bc6293 100644
--- a/nixos/modules/virtualisation/podman.nix
+++ b/nixos/modules/virtualisation/podman.nix
@@ -25,6 +25,7 @@ let
 in
 {
   imports = [
+    ./podman-network-socket.nix
     (lib.mkRenamedOptionModule [ "virtualisation" "podman" "libpod" ] [ "virtualisation" "containers" "containersConf" ])
   ];
 
@@ -46,6 +47,20 @@ in
         '';
       };
 
+    dockerSocket.enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Make the Podman socket available in place of the Docker socket, so
+        Docker tools can find the Podman socket.
+
+        Podman implements the Docker API.
+
+        Users must be in the <code>podman</code> group in order to connect. As
+        with Docker, members of this group can gain root access.
+      '';
+    };
+
     dockerCompat = mkOption {
       type = types.bool;
       default = false;
@@ -111,14 +126,36 @@ in
       };
 
       systemd.sockets.podman.wantedBy = [ "sockets.target" ];
+      systemd.sockets.podman.socketConfig.SocketGroup = "podman";
+
+      systemd.tmpfiles.packages = [
+        # The /run/podman rule interferes with our podman group, so we remove
+        # it and let the systemd socket logic take care of it.
+        (pkgs.runCommand "podman-tmpfiles-nixos" { package = cfg.package; } ''
+          mkdir -p $out/lib/tmpfiles.d/
+          grep -v 'D! /run/podman 0700 root root' \
+            <$package/lib/tmpfiles.d/podman.conf \
+            >$out/lib/tmpfiles.d/podman.conf
+        '') ];
 
-      systemd.tmpfiles.packages = [ cfg.package ];
+      systemd.tmpfiles.rules =
+        lib.optionals cfg.dockerSocket.enable [
+          "L! /run/docker.sock - - - - /run/podman/podman.sock"
+        ];
+
+      users.groups.podman = {};
 
       assertions = [
         {
           assertion = cfg.dockerCompat -> !config.virtualisation.docker.enable;
           message = "Option dockerCompat conflicts with docker";
         }
+        {
+          assertion = cfg.dockerSocket.enable -> !config.virtualisation.docker.enable;
+          message = ''
+            The options virtualisation.podman.dockerSocket.enable and virtualisation.docker.enable conflict, because only one can serve the socket.
+          '';
+        }
       ];
     }
   ]);