Add NetworkAlias= support to quadlet

Adds a `NetworkAlias=` key to both .container and .pod quadlet files,
which translates to the `--network-alias` option to `podman run` and
`podman pod create` respectively. Can be repeated multiple times.

Signed-off-by: Félix Saparelli <felix@passcod.name>

docs/source/markdown/podman-systemd.unit.5.md

@@ -282,6 +282,7 @@ Valid options for `[Container]` are listed below:
 | Mask=/proc/sys/foo\:/proc/sys/bar    | --security-opt mask=/proc/sys/foo:/proc/sys/bar      |
 | Mount=type=...                       | --mount type=...                                     |
 | Network=host                         | --net host                                           |
+| NetworkAlias=name                    | --network-alias name                                 |
 | NoNewPrivileges=true                 | --security-opt no-new-privileges                     |
 | Notify=true                          | --sdnotify container                                 |
 | PidsLimit=10000                      | --pids-limit 10000                                   |
@@ -594,6 +595,15 @@ created by using a `$name.network` Quadlet file.
 
 This key can be listed multiple times.
 
+### `NetworkAlias=`
+
+Add a network-scoped alias for the container. This has the same format as the `--network-alias`
+option to `podman run`. Aliases can be used to group containers together in DNS resolution: for
+example, setting `NetworkAlias=web` on multiple containers will make a DNS query for `web` resolve
+to all the containers with that alias.
+
+This key can be listed multiple times.
+
 ### `NoNewPrivileges=` (defaults to `false`)
 
 If enabled, this disables the container processes from gaining additional privileges via things like
@@ -828,6 +838,7 @@ Valid options for `[Pod]` are listed below:
 | ContainersConfModule=/etc/nvd\.conf | --module=/etc/nvd\.conf                |
 | GlobalArgs=--log-level=debug        | --log-level=debug                      |
 | Network=host                        | --network host                         |
+| NetworkAlias=name                   | --network-alias name                   |
 | PodmanArgs=\-\-cpus=2               | --cpus=2                               |
 | PodName=name                        | --name=name                            |
 | PublishPort=50-59                   | --publish 50-59                        |
@@ -866,6 +877,15 @@ or on `$name-network.service` if the `.network` unit is not found
 
 This key can be listed multiple times.
 
+### `NetworkAlias=`
+
+Add a network-scoped alias for the pod. This has the same format as the `--network-alias` option to
+`podman pod create`. Aliases can be used to group containers together in DNS resolution: for
+example, setting `NetworkAlias=web` on multiple containers will make a DNS query for `web` resolve
+to all the containers with that alias.
+
+This key can be listed multiple times.
+
 ### `PodmanArgs=`
 
 This key contains a list of arguments passed directly to the end of the `podman pod create` command

pkg/systemd/quadlet/quadlet.go

@@ -114,6 +114,7 @@ const (
 	KeyMask                  = "Mask"
 	KeyMount                 = "Mount"
 	KeyNetwork               = "Network"
+	KeyNetworkAlias          = "NetworkAlias"
 	KeyNetworkName           = "NetworkName"
 	KeyNoNewPrivileges       = "NoNewPrivileges"
 	KeyNotify                = "Notify"
@@ -217,6 +218,7 @@ var (
 		KeyMask:                  true,
 		KeyMount:                 true,
 		KeyNetwork:               true,
+		KeyNetworkAlias:          true,
 		KeyNoNewPrivileges:       true,
 		KeyNotify:                true,
 		KeyPidsLimit:             true,
@@ -363,6 +365,7 @@ var (
 		KeyContainersConfModule: true,
 		KeyGlobalArgs:           true,
 		KeyNetwork:              true,
+		KeyNetworkAlias:         true,
 		KeyPodName:              true,
 		KeyPodmanArgs:           true,
 		KeyPublishPort:          true,
@@ -560,6 +563,11 @@ func ConvertContainer(container *parser.UnitFile, names map[string]string, isUse
 
 	addNetworks(container, ContainerGroup, service, names, podman)
 
+	networkAliases := container.LookupAll(ContainerGroup, KeyNetworkAlias)
+	for _, networkAlias := range networkAliases {
+		podman.add("--network-alias", networkAlias)
+	}
+
 	// Run with a pid1 init to reap zombies by default (as most apps don't do that)
 	runInit, ok := container.LookupBoolean(ContainerGroup, KeyRunInit)
 	if ok {
@@ -1536,6 +1544,11 @@ func ConvertPod(podUnit *parser.UnitFile, name string, podsInfoMap map[string]*P
 
 	addNetworks(podUnit, PodGroup, service, names, execStartPre)
 
+	networkAliases := podUnit.LookupAll(PodGroup, KeyNetworkAlias)
+	for _, networkAlias := range networkAliases {
+		execStartPre.add("--network-alias", networkAlias)
+	}
+
 	if err := addVolumes(podUnit, service, PodGroup, names, execStartPre); err != nil {
 		return nil, err
 	}

test/e2e/quadlet/network-alias.container

@@ -0,0 +1,6 @@
+[Container]
+Image=localhost/imagename
+## assert-podman-args-key-val "--network-alias" "," "name"
+NetworkAlias=name
+## assert-podman-args-key-val "--network-alias" "," "othername"
+NetworkAlias=othername

test/e2e/quadlet/network-alias.pod

@@ -0,0 +1,6 @@
+## assert-podman-pre-args --network-alias name
+## assert-podman-pre-args --network-alias othername
+
+[Pod]
+NetworkAlias=name
+NetworkAlias=othername

test/e2e/quadlet_test.go

@@ -873,6 +873,7 @@ BOGUS=foo
 		Entry("template@.container", "template@.container", 0, ""),
 		Entry("template@instance.container", "template@instance.container", 0, ""),
 		Entry("Unit After Override", "unit-after-override.container", 0, ""),
+		Entry("NetworkAlias", "network-alias.container", 0, ""),
 
 		Entry("basic.volume", "basic.volume", 0, ""),
 		Entry("device-copy.volume", "device-copy.volume", 0, ""),
@@ -996,6 +997,7 @@ BOGUS=foo
 		Entry("network-quadlet.pod", "network.quadlet.pod", 0, ""),
 		Entry("podmanargs.pod", "podmanargs.pod", 0, ""),
 		Entry("volume.pod", "volume.pod", 0, ""),
+		Entry("Pod - NetworkAlias", "network-alias.pod", 0, ""),
 	)
 
 	DescribeTable("Running quadlet test case with dependencies",