Feat(gameservers): Add PodIP to GameServer Addresses (#3764)

Add a new `PodIP` type to the `GameServer.addresses` array; populate with any IPs on the Pod.

pkg/apis/agones/v1/gameserver.go

@@ -143,6 +143,9 @@ const (
 	// error state. The timestamp is encoded in RFC3339 format.
 	GameServerErroredAtAnnotation = agones.GroupName + "/errored-at"
 
+	// NodePodIP identifies an IP address from a pod.
+	NodePodIP corev1.NodeAddressType = "PodIP"
+
 	// True is the string "true" to appease the goconst lint.
 	True = "true"
 	// False is the string "false" to appease the goconst lint.

pkg/gameservers/controller.go

@@ -819,6 +819,12 @@ func (c *Controller) syncGameServerStartingState(ctx context.Context, gs *agones
 	if pod.Spec.NodeName == "" {
 		return gs, workerqueue.NewDebugError(errors.Errorf("node not yet populated for Pod %s", pod.ObjectMeta.Name))
 	}
+
+	// Ensure the pod IPs are populated
+	if pod.Status.PodIPs == nil || len(pod.Status.PodIPs) == 0 {
+		return gs, workerqueue.NewDebugError(errors.Errorf("pod IPs not yet populated for Pod %s", pod.ObjectMeta.Name))
+	}
+
 	node, err := c.nodeLister.Get(pod.Spec.NodeName)
 	if err != nil {
 		return gs, errors.Wrapf(err, "error retrieving node %s for Pod %s", pod.Spec.NodeName, pod.ObjectMeta.Name)

pkg/gameservers/controller_test.go

@@ -51,6 +51,7 @@ import (
 
 const (
 	ipFixture       = "12.12.12.12"
+	ipv6Fixture     = "2001:0db8:85a3:0000:0000:8a2e:0370:7334"
 	nodeFixtureName = "node1"
 )
 
@@ -88,6 +89,7 @@ func TestControllerSyncGameServer(t *testing.T) {
 			ca := action.(k8stesting.CreateAction)
 			pod := ca.GetObject().(*corev1.Pod)
 			pod.Spec.NodeName = node.ObjectMeta.Name
+			pod.Status.PodIPs = []corev1.PodIP{{IP: ipv6Fixture}}
 			podCreated = true
 			assert.Equal(t, fixture.ObjectMeta.Name, pod.ObjectMeta.Name)
 			watchPods.Add(pod)
@@ -120,7 +122,10 @@ func TestControllerSyncGameServer(t *testing.T) {
 			assert.Equal(t, expectedState, gs.Status.State)
 			if expectedState == agonesv1.GameServerStateScheduled {
 				assert.Equal(t, ipFixture, gs.Status.Address)
-				assert.Equal(t, []corev1.NodeAddress{{Address: ipFixture, Type: "ExternalIP"}}, gs.Status.Addresses)
+				assert.Equal(t, []corev1.NodeAddress{
+					{Address: ipFixture, Type: "ExternalIP"},
+					{Address: ipv6Fixture, Type: "PodIP"},
+				}, gs.Status.Addresses)
 				assert.NotEmpty(t, gs.Status.Ports[0].Port)
 			}
 
@@ -1093,6 +1098,7 @@ func TestControllerSyncGameServerStartingState(t *testing.T) {
 		pod, err := gsFixture.Pod(agtesting.FakeAPIHooks{})
 		assert.Nil(t, err)
 		pod.Spec.NodeName = nodeFixtureName
+		pod.Status.PodIPs = []corev1.PodIP{{IP: ipv6Fixture}}
 		gsUpdated := false
 
 		m.KubeClient.AddReactor("list", "nodes", func(action k8stesting.Action) (bool, runtime.Object, error) {
@@ -1118,19 +1124,50 @@ func TestControllerSyncGameServerStartingState(t *testing.T) {
 		assert.True(t, gsUpdated)
 		assert.Equal(t, gs.Status.NodeName, node.ObjectMeta.Name)
 		assert.Equal(t, gs.Status.Address, ipFixture)
-		assert.Equal(t, []corev1.NodeAddress{{Address: ipFixture, Type: "ExternalIP"}}, gs.Status.Addresses)
+		assert.Equal(t, []corev1.NodeAddress{
+			{Address: ipFixture, Type: "ExternalIP"},
+			{Address: ipv6Fixture, Type: "PodIP"},
+		}, gs.Status.Addresses)
 
 		agtesting.AssertEventContains(t, m.FakeRecorder.Events, "Address and port populated")
 		assert.NotEmpty(t, gs.Status.Ports)
 	})
 
+	t.Run("Error on podIPs not populated", func(t *testing.T) {
+		c, m := newFakeController()
+		gsFixture := newFixture()
+		gsFixture.ApplyDefaults()
+		pod, err := gsFixture.Pod(agtesting.FakeAPIHooks{})
+		require.NoError(t, err)
+		pod.Spec.NodeName = nodeFixtureName
+
+		m.KubeClient.AddReactor("list", "nodes", func(action k8stesting.Action) (bool, runtime.Object, error) {
+			return true, &corev1.NodeList{Items: []corev1.Node{node}}, nil
+		})
+		m.KubeClient.AddReactor("list", "pods", func(action k8stesting.Action) (bool, runtime.Object, error) {
+			return true, &corev1.PodList{Items: []corev1.Pod{*pod}}, nil
+		})
+		m.AgonesClient.AddReactor("update", "gameservers", func(action k8stesting.Action) (bool, runtime.Object, error) {
+			ua := action.(k8stesting.UpdateAction)
+			gs := ua.GetObject().(*agonesv1.GameServer)
+			assert.Equal(t, agonesv1.GameServerStateScheduled, gs.Status.State)
+			return true, gs, errors.New("update-err")
+		})
+		ctx, cancel := agtesting.StartInformers(m, c.gameServerSynced, c.podSynced, c.nodeSynced)
+		defer cancel()
+
+		_, err = c.syncGameServerStartingState(ctx, gsFixture)
+		assert.Error(t, err)
+	})
+
 	t.Run("Error on update", func(t *testing.T) {
 		c, m := newFakeController()
 		gsFixture := newFixture()
 		gsFixture.ApplyDefaults()
 		pod, err := gsFixture.Pod(agtesting.FakeAPIHooks{})
 		require.NoError(t, err)
 		pod.Spec.NodeName = nodeFixtureName
+		pod.Status.PodIPs = []corev1.PodIP{{IP: ipv6Fixture}}
 
 		m.KubeClient.AddReactor("list", "nodes", func(action k8stesting.Action) (bool, runtime.Object, error) {
 			return true, &corev1.NodeList{Items: []corev1.Node{node}}, nil

pkg/gameservers/gameservers.go

@@ -88,6 +88,13 @@ func applyGameServerAddressAndPort(gs *agonesv1.GameServer, node *corev1.Node, p
 	gs.Status.Addresses = addrs
 	gs.Status.NodeName = pod.Spec.NodeName
 
+	for _, ip := range pod.Status.PodIPs {
+		gs.Status.Addresses = append(gs.Status.Addresses, corev1.NodeAddress{
+			Type:    agonesv1.NodePodIP,
+			Address: ip.IP,
+		})
+	}
+
 	if err := syncPodPortsToGameServer(gs, pod); err != nil {
 		return gs, errors.Wrapf(err, "cloud product error syncing ports on GameServer %s", gs.ObjectMeta.Name)
 	}

pkg/gameservers/gameservers_test.go

@@ -136,6 +136,7 @@ func TestApplyGameServerAddressAndPort(t *testing.T) {
 			pod, err := gsFixture.Pod(agtesting.FakeAPIHooks{})
 			require.NoError(t, err)
 			pod.Spec.NodeName = node.ObjectMeta.Name
+			pod.Status.PodIPs = []corev1.PodIP{{IP: ipFixture}}
 			tc.podMod(pod)
 
 			gs, err := applyGameServerAddressAndPort(gsFixture, node, pod, tc.podSyncer)
@@ -146,6 +147,10 @@ func TestApplyGameServerAddressAndPort(t *testing.T) {
 			}
 			assert.Equal(t, ipFixture, gs.Status.Address)
 			assert.Equal(t, node.ObjectMeta.Name, gs.Status.NodeName)
+			assert.Equal(t, []corev1.NodeAddress{
+				{Address: ipFixture, Type: "ExternalIP"},
+				{Address: ipFixture, Type: "PodIP"},
+			}, gs.Status.Addresses)
 		})
 	}
 

site/content/en/docs/Reference/gameserver.md

@@ -190,7 +190,7 @@ Game Servers are created through Kubernetes API (either directly or through a [F
 
 [`GameServer.Status`][gss] has two fields which reflect the network address of the `GameServer`: `address` and `addresses`.
 The `address` field is a policy-based choice of "primary address" that will work for many use cases,
-and will always be one of the `addresses`. The `addresses` field contains every address in the [`Node.Status.addresses`][addresses],
+and will always be one of the `addresses`. The `addresses` field contains every address in the [`Node.Status.addresses`][addresses] and [`Pod.Status.podIPs`][podIPs] (to allow a direct pod access),
 representing all known ways to reach the `GameServer` over the network.
 
 To choose `address` from `addresses`, [Agones looks for the following address types][addressFunc], in highest to lowest priorty:
@@ -199,11 +199,13 @@ To choose `address` from `addresses`, [Agones looks for the following address ty
 * `InternalDNS`
 * `InternalIP`
 
-e.g. if any `ExternalDNS` address is found in the respective `Node`, it is used as the `address`.
+e.g. if any `ExternalDNS` address is found in the respective `Node`, it is used as the `address`. (`PodIP` is not considered
+for `address`.)
 
 The policy for `address` will work for many use-cases, but for some advanced cases, such as IPv6 enablement, you may need
 to evaluate all `addresses` and pick the addresses that best suits your needs.
 
 [addresses]: https://v1-26.docs.kubernetes.io/docs/reference/generated/kubernetes-api/v1.26/#nodeaddress-v1-core
+[podIPs]: https://v1-26.docs.kubernetes.io/docs/reference/generated/kubernetes-api/v1.26/#podip-v1-core
 [addressFunc]: https://github.com/googleforgames/agones/blob/a59c5394c7f5bac66e530d21446302581c10c225/pkg/gameservers/gameservers.go#L37-L71
 [gss]: {{% ref "/docs/Reference/agones_crd_api_reference.html#agones.dev/v1.GameServerStatus"  %}}

test/e2e/gameserver_test.go

@@ -60,6 +60,16 @@ func TestCreateConnect(t *testing.T) {
 	assert.NotEmpty(t, readyGs.Status.Ports[0].Port)
 	assert.NotEmpty(t, readyGs.Status.Address)
 	assert.NotEmpty(t, readyGs.Status.Addresses)
+
+	var hasPodIPAddress bool
+	for i, addr := range readyGs.Status.Addresses {
+		if addr.Type == agonesv1.NodePodIP {
+			assert.NotEmpty(t, readyGs.Status.Addresses[i].Address)
+			hasPodIPAddress = true
+		}
+	}
+	assert.True(t, hasPodIPAddress)
+
 	assert.NotEmpty(t, readyGs.Status.NodeName)
 	assert.Equal(t, readyGs.Status.State, agonesv1.GameServerStateReady)