kubenet for ipv6 dualstack

pkg/kubelet/config/common_test.go

@@ -63,6 +63,14 @@ func TestDecodeSinglePod(t *testing.T) {
 			SchedulerName:      core.DefaultSchedulerName,
 			EnableServiceLinks: &enableServiceLinks,
 		},
+		Status: v1.PodStatus{
+			PodIP: "1.2.3.4",
+			PodIPs: []v1.PodIP{
+				{
+					IP: "1.2.3.4",
+				},
+			},
+		},
 	}
 	json, err := runtime.Encode(testapi.Default.Codec(), pod)
 	if err != nil {
@@ -128,6 +136,14 @@ func TestDecodePodList(t *testing.T) {
 			SchedulerName:      core.DefaultSchedulerName,
 			EnableServiceLinks: &enableServiceLinks,
 		},
+		Status: v1.PodStatus{
+			PodIP: "1.2.3.4",
+			PodIPs: []v1.PodIP{
+				{
+					IP: "1.2.3.4",
+				},
+			},
+		},
 	}
 	podList := &v1.PodList{
 		Items: []v1.Pod{*pod},

pkg/kubelet/container/runtime.go

@@ -273,8 +273,8 @@ type PodStatus struct {
 	Name string
 	// Namespace of the pod.
 	Namespace string
-	// IP of the pod.
-	IP string
+	// All IPs assigned to this pod
+	IPs []string
 	// Status of containers in the pod.
 	ContainerStatuses []*ContainerStatus
 	// Status of the pod sandbox.

pkg/kubelet/dockershim/docker_sandbox.go

@@ -324,65 +324,75 @@ func (ds *dockerService) RemovePodSandbox(ctx context.Context, r *runtimeapi.Rem
 	return nil, utilerrors.NewAggregate(errs)
 }
 
-// getIPFromPlugin interrogates the network plugin for an IP.
-func (ds *dockerService) getIPFromPlugin(sandbox *dockertypes.ContainerJSON) (string, error) {
+// getIPsFromPlugin interrogates the network plugin for sandbox IPs.
+func (ds *dockerService) getIPsFromPlugin(sandbox *dockertypes.ContainerJSON) ([]string, error) {
 	metadata, err := parseSandboxName(sandbox.Name)
 	if err != nil {
-		return "", err
+		return nil, err
 	}
 	msg := fmt.Sprintf("Couldn't find network status for %s/%s through plugin", metadata.Namespace, metadata.Name)
 	cID := kubecontainer.BuildContainerID(runtimeName, sandbox.ID)
 	networkStatus, err := ds.network.GetPodNetworkStatus(metadata.Namespace, metadata.Name, cID)
 	if err != nil {
-		return "", err
+		return nil, err
 	}
 	if networkStatus == nil {
-		return "", fmt.Errorf("%v: invalid network status for", msg)
+		return nil, fmt.Errorf("%v: invalid network status for", msg)
 	}
-	return networkStatus.IP.String(), nil
+
+	ips := make([]string, 0)
+	for _, ip := range networkStatus.IPs {
+		ips = append(ips, ip.String())
+	}
+	// if we don't have any ip in our list then cni is using classic primary IP only
+	if len(ips) == 0 {
+		ips = append(ips, networkStatus.IP.String())
+	}
+	return ips, nil
 }
 
-// getIP returns the ip given the output of `docker inspect` on a pod sandbox,
+// getIPs returns the ip given the output of `docker inspect` on a pod sandbox,
 // first interrogating any registered plugins, then simply trusting the ip
 // in the sandbox itself. We look for an ipv4 address before ipv6.
-func (ds *dockerService) getIP(podSandboxID string, sandbox *dockertypes.ContainerJSON) string {
+func (ds *dockerService) getIPs(podSandboxID string, sandbox *dockertypes.ContainerJSON) []string {
 	if sandbox.NetworkSettings == nil {
-		return ""
+		return nil
 	}
 	if networkNamespaceMode(sandbox) == runtimeapi.NamespaceMode_NODE {
 		// For sandboxes using host network, the shim is not responsible for
 		// reporting the IP.
-		return ""
+		return nil
 	}
 
 	// Don't bother getting IP if the pod is known and networking isn't ready
 	ready, ok := ds.getNetworkReady(podSandboxID)
 	if ok && !ready {
-		return ""
+		return nil
 	}
 
-	ip, err := ds.getIPFromPlugin(sandbox)
+	ips, err := ds.getIPsFromPlugin(sandbox)
 	if err == nil {
-		return ip
+		return ips
 	}
 
+	ips = make([]string, 0)
 	// TODO: trusting the docker ip is not a great idea. However docker uses
 	// eth0 by default and so does CNI, so if we find a docker IP here, we
 	// conclude that the plugin must have failed setup, or forgotten its ip.
 	// This is not a sensible assumption for plugins across the board, but if
 	// a plugin doesn't want this behavior, it can throw an error.
 	if sandbox.NetworkSettings.IPAddress != "" {
-		return sandbox.NetworkSettings.IPAddress
+		ips = append(ips, sandbox.NetworkSettings.IPAddress)
 	}
 	if sandbox.NetworkSettings.GlobalIPv6Address != "" {
-		return sandbox.NetworkSettings.GlobalIPv6Address
+		ips = append(ips, sandbox.NetworkSettings.GlobalIPv6Address)
 	}
 
 	// If all else fails, warn but don't return an error, as pod status
 	// should generally not return anything except fatal errors
 	// FIXME: handle network errors by restarting the pod somehow?
 	klog.Warningf("failed to read pod IP from plugin/docker: %v", err)
-	return ""
+	return ips
 }
 
 // Returns the inspect container response, the sandbox metadata, and network namespace mode
@@ -422,11 +432,19 @@ func (ds *dockerService) PodSandboxStatus(ctx context.Context, req *runtimeapi.P
 		state = runtimeapi.PodSandboxState_SANDBOX_READY
 	}
 
-	var IP string
+	var ips []string
 	// TODO: Remove this when sandbox is available on windows
 	// This is a workaround for windows, where sandbox is not in use, and pod IP is determined through containers belonging to the Pod.
-	if IP = ds.determinePodIPBySandboxID(podSandboxID); IP == "" {
-		IP = ds.getIP(podSandboxID, r)
+	if ips = ds.determinePodIPBySandboxID(podSandboxID); len(ips) == 0 {
+		ips = ds.getIPs(podSandboxID, r)
+	}
+
+	// ip is primary ips
+	// ips is all other ips
+	ip := ""
+	if len(ips) != 0 {
+		ip = ips[0]
+		ips = ips[1:]
 	}
 
 	labels, annotations := extractLabels(r.Config.Labels)
@@ -438,7 +456,7 @@ func (ds *dockerService) PodSandboxStatus(ctx context.Context, req *runtimeapi.P
 		Labels:      labels,
 		Annotations: annotations,
 		Network: &runtimeapi.PodSandboxNetworkStatus{
-			Ip: IP,
+			Ip: ip,
 		},
 		Linux: &runtimeapi.LinuxPodSandboxStatus{
 			Namespaces: &runtimeapi.Namespace{
@@ -450,6 +468,14 @@ func (ds *dockerService) PodSandboxStatus(ctx context.Context, req *runtimeapi.P
 			},
 		},
 	}
+	// add additional IPs
+	additionalPodIPs := make([]*runtimeapi.PodIP, 0, len(ips))
+	for _, ip := range ips {
+		additionalPodIPs = append(additionalPodIPs, &runtimeapi.PodIP{
+			Ip: ip,
+		})
+	}
+	status.Network.AdditionalIps = additionalPodIPs
 	return &runtimeapi.PodSandboxStatusResponse{Status: status}, nil
 }
 

pkg/kubelet/dockershim/docker_sandbox_test.go

@@ -106,7 +106,7 @@ func TestSandboxStatus(t *testing.T) {
 		State:     state,
 		CreatedAt: ct,
 		Metadata:  config.Metadata,
-		Network:   &runtimeapi.PodSandboxNetworkStatus{Ip: podIP},
+		Network:   &runtimeapi.PodSandboxNetworkStatus{Ip: podIP, AdditionalIps: []*runtimeapi.PodIP{}},
 		Linux: &runtimeapi.LinuxPodSandboxStatus{
 			Namespaces: &runtimeapi.Namespace{
 				Options: &runtimeapi.NamespaceOption{
@@ -142,6 +142,7 @@ func TestSandboxStatus(t *testing.T) {
 	require.NoError(t, err)
 	// IP not valid after sandbox stop
 	expected.Network.Ip = ""
+	expected.Network.AdditionalIps = []*runtimeapi.PodIP{}
 	statusResp, err = ds.PodSandboxStatus(getTestCTX(), &runtimeapi.PodSandboxStatusRequest{PodSandboxId: id})
 	require.NoError(t, err)
 	assert.Equal(t, expected, statusResp.Status)
@@ -161,14 +162,13 @@ func TestSandboxStatusAfterRestart(t *testing.T) {
 	config := makeSandboxConfig("foo", "bar", "1", 0)
 	r := rand.New(rand.NewSource(0)).Uint32()
 	podIP := fmt.Sprintf("10.%d.%d.%d", byte(r>>16), byte(r>>8), byte(r))
-
 	state := runtimeapi.PodSandboxState_SANDBOX_READY
 	ct := int64(0)
 	expected := &runtimeapi.PodSandboxStatus{
 		State:     state,
 		CreatedAt: ct,
 		Metadata:  config.Metadata,
-		Network:   &runtimeapi.PodSandboxNetworkStatus{Ip: podIP},
+		Network:   &runtimeapi.PodSandboxNetworkStatus{Ip: podIP, AdditionalIps: []*runtimeapi.PodIP{}},
 		Linux: &runtimeapi.LinuxPodSandboxStatus{
 			Namespaces: &runtimeapi.Namespace{
 				Options: &runtimeapi.NamespaceOption{

pkg/kubelet/dockershim/helpers_linux.go

@@ -136,8 +136,8 @@ func (ds *dockerService) updateCreateConfig(
 	return nil
 }
 
-func (ds *dockerService) determinePodIPBySandboxID(uid string) string {
-	return ""
+func (ds *dockerService) determinePodIPBySandboxID(uid string) []string {
+	return nil
 }
 
 func getNetworkNamespace(c *dockertypes.ContainerJSON) (string, error) {

pkg/kubelet/dockershim/helpers_unsupported.go

@@ -45,9 +45,9 @@ func (ds *dockerService) updateCreateConfig(
 	return nil
 }
 
-func (ds *dockerService) determinePodIPBySandboxID(uid string) string {
+func (ds *dockerService) determinePodIPBySandboxID(uid string) []string {
 	klog.Warningf("determinePodIPBySandboxID is unsupported in this build")
-	return ""
+	return nil
 }
 
 func getNetworkNamespace(c *dockertypes.ContainerJSON) (string, error) {

pkg/kubelet/dockershim/helpers_windows.go

@@ -97,7 +97,7 @@ func applyWindowsContainerSecurityContext(wsc *runtimeapi.WindowsContainerSecuri
 	}
 }
 
-func (ds *dockerService) determinePodIPBySandboxID(sandboxID string) string {
+func (ds *dockerService) determinePodIPBySandboxID(sandboxID string) []string {
 	opts := dockertypes.ContainerListOptions{
 		All:     true,
 		Filters: dockerfilters.NewArgs(),
@@ -108,7 +108,7 @@ func (ds *dockerService) determinePodIPBySandboxID(sandboxID string) string {
 	f.AddLabel(sandboxIDLabelKey, sandboxID)
 	containers, err := ds.client.ListContainers(opts)
 	if err != nil {
-		return ""
+		return nil
 	}
 
 	for _, c := range containers {
@@ -144,8 +144,8 @@ func (ds *dockerService) determinePodIPBySandboxID(sandboxID string) string {
 				// Hyper-V only supports one container per Pod yet and the container will have a different
 				// IP address from sandbox. Return the first non-sandbox container IP as POD IP.
 				// TODO(feiskyer): remove this workaround after Hyper-V supports multiple containers per Pod.
-				if containerIP := ds.getIP(c.ID, r); containerIP != "" {
-					return containerIP
+				if containerIPs := ds.getIPs(c.ID, r); len(containerIPs) != 0 {
+					return containerIPs
 				}
 			} else {
 				// Do not return any IP, so that we would continue and get the IP of the Sandbox.
@@ -153,17 +153,17 @@ func (ds *dockerService) determinePodIPBySandboxID(sandboxID string) string {
 				// to replicate the DNS registry key to the Workload container (IP/Gateway/MAC is
 				// set separately than DNS).
 				// TODO(feiskyer): remove this workaround after Namespace is supported in Windows RS5.
-				ds.getIP(sandboxID, r)
+				ds.getIPs(sandboxID, r)
 			}
 		} else {
 			// ds.getIP will call the CNI plugin to fetch the IP
-			if containerIP := ds.getIP(c.ID, r); containerIP != "" {
-				return containerIP
+			if containerIPs := ds.getIPs(c.ID, r); len(containerIPs) != 0 {
+				return containerIPs
 			}
 		}
 	}
 
-	return ""
+	return nil
 }
 
 func getNetworkNamespace(c *dockertypes.ContainerJSON) (string, error) {

pkg/kubelet/dockershim/network/BUILD

@@ -9,6 +9,7 @@ go_library(
     importpath = "k8s.io/kubernetes/pkg/kubelet/dockershim/network",
     visibility = ["//visibility:public"],
     deps = [
+        "//pkg/features:go_default_library",
         "//pkg/kubelet/apis/config:go_default_library",
         "//pkg/kubelet/container:go_default_library",
         "//pkg/kubelet/dockershim/network/hostport:go_default_library",
@@ -18,6 +19,7 @@ go_library(
         "//staging/src/k8s.io/apimachinery/pkg/util/errors:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/validation:go_default_library",
+        "//staging/src/k8s.io/apiserver/pkg/util/feature:go_default_library",
         "//vendor/k8s.io/klog:go_default_library",
         "//vendor/k8s.io/utils/exec:go_default_library",
     ],

pkg/kubelet/dockershim/network/cni/cni_others.go

@@ -69,12 +69,15 @@ func (plugin *cniNetworkPlugin) GetPodNetworkStatus(namespace string, name strin
 		return nil, fmt.Errorf("Cannot find the network namespace, skipping pod network status for container %q", id)
 	}
 
-	ip, err := network.GetPodIP(plugin.execer, plugin.nsenterPath, netnsPath, network.DefaultInterfaceName)
+	ips, err := network.GetPodIPs(plugin.execer, plugin.nsenterPath, netnsPath, network.DefaultInterfaceName)
 	if err != nil {
 		return nil, err
 	}
 
-	return &network.PodNetworkStatus{IP: ip}, nil
+	return &network.PodNetworkStatus{
+		IP:  ips[0],
+		IPs: ips,
+	}, nil
 }
 
 // buildDNSCapabilities builds cniDNSConfig from runtimeapi.DNSConfig.

pkg/kubelet/dockershim/network/kubenet/BUILD

@@ -36,6 +36,7 @@ go_library(
             "//pkg/kubelet/dockershim/network:go_default_library",
         ],
         "@io_bazel_rules_go//go/platform:linux": [
+            "//pkg/features:go_default_library",
             "//pkg/kubelet/apis/config:go_default_library",
             "//pkg/kubelet/container:go_default_library",
             "//pkg/kubelet/dockershim/network:go_default_library",
@@ -48,6 +49,7 @@ go_library(
             "//staging/src/k8s.io/apimachinery/pkg/util/errors:go_default_library",
             "//staging/src/k8s.io/apimachinery/pkg/util/net:go_default_library",
             "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
+            "//staging/src/k8s.io/apiserver/pkg/util/feature:go_default_library",
             "//vendor/github.com/containernetworking/cni/libcni:go_default_library",
             "//vendor/github.com/containernetworking/cni/pkg/types:go_default_library",
             "//vendor/github.com/containernetworking/cni/pkg/types/020:go_default_library",
@@ -55,6 +57,7 @@ go_library(
             "//vendor/golang.org/x/sys/unix:go_default_library",
             "//vendor/k8s.io/klog:go_default_library",
             "//vendor/k8s.io/utils/exec:go_default_library",
+            "//vendor/k8s.io/utils/net:go_default_library",
         ],
         "@io_bazel_rules_go//go/platform:nacl": [
             "//pkg/kubelet/apis/config:go_default_library",
@@ -105,6 +108,7 @@ go_test(
             "//pkg/util/bandwidth:go_default_library",
             "//pkg/util/iptables/testing:go_default_library",
             "//pkg/util/sysctl/testing:go_default_library",
+            "//staging/src/k8s.io/apimachinery/pkg/util/sets:go_default_library",
             "//vendor/github.com/stretchr/testify/assert:go_default_library",
             "//vendor/github.com/stretchr/testify/mock:go_default_library",
             "//vendor/k8s.io/utils/exec:go_default_library",

pkg/kubelet/dockershim/network/kubenet/kubenet_linux.go

@@ -46,6 +46,10 @@ import (
 	utiliptables "k8s.io/kubernetes/pkg/util/iptables"
 	utilsysctl "k8s.io/kubernetes/pkg/util/sysctl"
 	utilexec "k8s.io/utils/exec"
+
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	kubefeatures "k8s.io/kubernetes/pkg/features"
+	netutils "k8s.io/utils/net"
 )
 
 const (
@@ -63,6 +67,29 @@ const (
 	// defaultIPAMDir is the default location for the checkpoint files stored by host-local ipam
 	// https://github.com/containernetworking/cni/tree/master/plugins/ipam/host-local#backends
 	defaultIPAMDir = "/var/lib/cni/networks"
+
+	zeroCIDRv6 = "::/0"
+	zeroCIDRv4 = "0.0.0.0/0"
+
+	NET_CONFIG_TEMPLATE = `{
+  "cniVersion": "0.1.0",
+  "name": "kubenet",
+  "type": "bridge",
+  "bridge": "%s",
+  "mtu": %d,
+  "addIf": "%s",
+  "isGateway": true,
+  "ipMasq": false,
+  "hairpinMode": %t,
+  "ipam": {
+    "type": "host-local",
+    "ranges": [%s],
+    "routes": [
+      { "dst": "%s" },
+      { "dst": "%s" }
+    ]
+  }
+}`
 )
 
 // CNI plugins required by kubenet in /opt/cni/bin or user-specified directory
@@ -77,7 +104,7 @@ type kubenetNetworkPlugin struct {
 	cniConfig       libcni.CNI
 	bandwidthShaper bandwidth.Shaper
 	mu              sync.Mutex //Mutex for protecting podIPs map, netConfig, and shaper initialization
-	podIPs          map[kubecontainer.ContainerID]string
+	podIPs          map[kubecontainer.ContainerID]utilsets.String
 	mtu             int
 	execer          utilexec.Interface
 	nsenterPath     string
@@ -88,33 +115,36 @@ type kubenetNetworkPlugin struct {
 	hostportSyncer  hostport.HostportSyncer
 	hostportManager hostport.HostPortManager
 	iptables        utiliptables.Interface
+	iptablesv6      utiliptables.Interface
 	sysctl          utilsysctl.Interface
 	ebtables        utilebtables.Interface
 	// binDirs is passed by kubelet cni-bin-dir parameter.
 	// kubenet will search for CNI binaries in DefaultCNIDir first, then continue to binDirs.
 	binDirs           []string
 	nonMasqueradeCIDR string
-	podCidr           string
-	gateway           net.IP
 	cacheDir          string
+	podCIDRs          []*net.IPNet
+	podGateways       []net.IP
 }
 
 func NewPlugin(networkPluginDirs []string, cacheDir string) network.NetworkPlugin {
-	protocol := utiliptables.ProtocolIpv4
 	execer := utilexec.New()
 	dbus := utildbus.New()
-	sysctl := utilsysctl.New()
-	iptInterface := utiliptables.New(execer, dbus, protocol)
+	iptInterface := utiliptables.New(execer, dbus, utiliptables.ProtocolIpv4)
+	iptInterfacev6 := utiliptables.New(execer, dbus, utiliptables.ProtocolIpv6)
 	return &kubenetNetworkPlugin{
-		podIPs:            make(map[kubecontainer.ContainerID]string),
+		podIPs:            make(map[kubecontainer.ContainerID]utilsets.String),
 		execer:            utilexec.New(),
 		iptables:          iptInterface,
-		sysctl:            sysctl,
+		iptablesv6:        iptInterfacev6,
+		sysctl:            utilsysctl.New(),
 		binDirs:           append([]string{DefaultCNIDir}, networkPluginDirs...),
 		hostportSyncer:    hostport.NewHostportSyncer(iptInterface),
 		hostportManager:   hostport.NewHostportManager(iptInterface),
 		nonMasqueradeCIDR: "10.0.0.0/8",
 		cacheDir:          cacheDir,
+		podCIDRs:          make([]*net.IPNet, 0),
+		podGateways:       make([]net.IP, 0),
 	}
 }
 
@@ -171,8 +201,14 @@ func (plugin *kubenetNetworkPlugin) Init(host network.Host, hairpinMode kubeletc
 
 // TODO: move thic logic into cni bridge plugin and remove this from kubenet
 func (plugin *kubenetNetworkPlugin) ensureMasqRule() error {
-	if plugin.nonMasqueradeCIDR != "0.0.0.0/0" {
-		if _, err := plugin.iptables.EnsureRule(utiliptables.Append, utiliptables.TableNAT, utiliptables.ChainPostrouting,
+	if plugin.nonMasqueradeCIDR != zeroCIDRv4 && plugin.nonMasqueradeCIDR != zeroCIDRv6 {
+		// switch according to target nonMasqueradeCidr ip family
+		ipt := plugin.iptables
+		if netutils.IsIPv6CIDRString(plugin.nonMasqueradeCIDR) {
+			ipt = plugin.iptablesv6
+		}
+
+		if _, err := ipt.EnsureRule(utiliptables.Append, utiliptables.TableNAT, utiliptables.ChainPostrouting,
 			"-m", "comment", "--comment", "kubenet: SNAT for outbound traffic from cluster",
 			"-m", "addrtype", "!", "--dst-type", "LOCAL",
 			"!", "-d", plugin.nonMasqueradeCIDR,
@@ -207,27 +243,8 @@ func findMinMTU() (*net.Interface, error) {
 	return &intfs[defIntfIndex], nil
 }
 
-const NET_CONFIG_TEMPLATE = `{
-  "cniVersion": "0.1.0",
-  "name": "kubenet",
-  "type": "bridge",
-  "bridge": "%s",
-  "mtu": %d,
-  "addIf": "%s",
-  "isGateway": true,
-  "ipMasq": false,
-  "hairpinMode": %t,
-  "ipam": {
-    "type": "host-local",
-    "subnet": "%s",
-    "gateway": "%s",
-    "routes": [
-      { "dst": "0.0.0.0/0" }
-    ]
-  }
-}`
-
 func (plugin *kubenetNetworkPlugin) Event(name string, details map[string]interface{}) {
+	var err error
 	if name != network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE {
 		return
 	}
@@ -246,33 +263,54 @@ func (plugin *kubenetNetworkPlugin) Event(name string, details map[string]interf
 		return
 	}
 
-	klog.V(5).Infof("PodCIDR is set to %q", podCIDR)
-	_, cidr, err := net.ParseCIDR(podCIDR)
-	if err == nil {
-		setHairpin := plugin.hairpinMode == kubeletconfig.HairpinVeth
-		// Set bridge address to first address in IPNet
-		cidr.IP[len(cidr.IP)-1] += 1
+	klog.V(4).Infof("kubenet: PodCIDR is set to %q", podCIDR)
+	podCIDRs := strings.Split(podCIDR, ",")
 
-		json := fmt.Sprintf(NET_CONFIG_TEMPLATE, BridgeName, plugin.mtu, network.DefaultInterfaceName, setHairpin, podCIDR, cidr.IP.String())
-		klog.V(2).Infof("CNI network config set to %v", json)
-		plugin.netConfig, err = libcni.ConfFromBytes([]byte(json))
-		if err == nil {
-			klog.V(5).Infof("CNI network config:\n%s", json)
-
-			// Ensure cbr0 has no conflicting addresses; CNI's 'bridge'
-			// plugin will bail out if the bridge has an unexpected one
-			plugin.clearBridgeAddressesExcept(cidr)
-		}
-		plugin.podCidr = podCIDR
-		plugin.gateway = cidr.IP
+	// reset to one cidr if dual stack is not enabled
+	if !utilfeature.DefaultFeatureGate.Enabled(kubefeatures.IPv6DualStack) && len(podCIDRs) > 1 {
+		klog.V(2).Infof("This node has multiple pod cidrs assigned and dual stack is not enabled. ignoring all except first cidr")
+		podCIDRs = podCIDRs[0:1]
 	}
 
+	for idx, currentPodCIDR := range podCIDRs {
+		_, cidr, err := net.ParseCIDR(currentPodCIDR)
+		if nil != err {
+			klog.Warningf("Failed to generate CNI network config with cidr %s at indx:%v: %v", currentPodCIDR, idx, err)
+			return
+		}
+		// create list of ips and gateways
+		cidr.IP[len(cidr.IP)-1] += 1 // Set bridge address to first address in IPNet
+		plugin.podCIDRs = append(plugin.podCIDRs, cidr)
+		plugin.podGateways = append(plugin.podGateways, cidr.IP)
+	}
+
+	//setup hairpinMode
+	setHairpin := plugin.hairpinMode == kubeletconfig.HairpinVeth
+
+	json := fmt.Sprintf(NET_CONFIG_TEMPLATE, BridgeName, plugin.mtu, network.DefaultInterfaceName, setHairpin, plugin.getRangesConfig(), zeroCIDRv4, zeroCIDRv6)
+	klog.V(4).Infof("CNI network config set to %v", json)
+	plugin.netConfig, err = libcni.ConfFromBytes([]byte(json))
 	if err != nil {
-		klog.Warningf("Failed to generate CNI network config: %v", err)
+		klog.Warningf("** failed to set up CNI with %v err:%v", json, err)
+		// just incase it was set by mistake
+		plugin.netConfig = nil
+		// we bail out by clearing the *entire* list
+		// of addresses assigned to cbr0
+		plugin.clearUnusedBridgeAddresses()
 	}
 }
 
-func (plugin *kubenetNetworkPlugin) clearBridgeAddressesExcept(keep *net.IPNet) {
+// clear all address on bridge except those operated on by kubenet
+func (plugin *kubenetNetworkPlugin) clearUnusedBridgeAddresses() {
+	cidrIncluded := func(list []*net.IPNet, check *net.IPNet) bool {
+		for _, thisNet := range list {
+			if utilnet.IPNetEqual(thisNet, check) {
+				return true
+			}
+		}
+		return false
+	}
+
 	bridge, err := netlink.LinkByName(BridgeName)
 	if err != nil {
 		return
@@ -280,11 +318,12 @@ func (plugin *kubenetNetworkPlugin) clearBridgeAddressesExcept(keep *net.IPNet)
 
 	addrs, err := netlink.AddrList(bridge, unix.AF_INET)
 	if err != nil {
+		klog.V(2).Infof("attempting to get address for interface: %s failed with err:%v", BridgeName, err)
 		return
 	}
 
 	for _, addr := range addrs {
-		if !utilnet.IPNetEqual(addr.IPNet, keep) {
+		if !cidrIncluded(plugin.podCIDRs, addr.IPNet) {
 			klog.V(2).Infof("Removing old address %s from %s", addr.IPNet.String(), BridgeName)
 			netlink.AddrDel(bridge, &addr)
 		}
@@ -301,6 +340,7 @@ func (plugin *kubenetNetworkPlugin) Capabilities() utilsets.Int {
 
 // setup sets up networking through CNI using the given ns/name and sandbox ID.
 func (plugin *kubenetNetworkPlugin) setup(namespace string, name string, id kubecontainer.ContainerID, annotations map[string]string) error {
+	var ipv4, ipv6 net.IP
 	// Disable DAD so we skip the kernel delay on bringing up new interfaces.
 	if err := plugin.disableContainerDAD(id); err != nil {
 		klog.V(3).Infof("Failed to disable DAD in container: %v", err)
@@ -321,14 +361,19 @@ func (plugin *kubenetNetworkPlugin) setup(namespace string, name string, id kube
 	if err != nil {
 		return fmt.Errorf("unable to understand network config: %v", err)
 	}
-	if res.IP4 == nil {
-		return fmt.Errorf("CNI plugin reported no IPv4 address for container %v.", id)
-	}
-	ip4 := res.IP4.IP.IP.To4()
-	if ip4 == nil {
-		return fmt.Errorf("CNI plugin reported an invalid IPv4 address for container %v: %+v.", id, res.IP4)
+	//TODO: v1.16 (khenidak) update NET_CONFIG_TEMPLATE to CNI version 0.3.0 or later so
+	// that we get multiple IP addresses in the returned Result structure
+	if res.IP4 != nil {
+		ipv4 = res.IP4.IP.IP.To4()
 	}
 
+	if res.IP6 != nil {
+		ipv6 = res.IP6.IP.IP
+	}
+
+	if ipv4 == nil && ipv6 == nil {
+		return fmt.Errorf("cni didn't report ipv4 ipv6")
+	}
 	// Put the container bridge into promiscuous mode to force it to accept hairpin packets.
 	// TODO: Remove this once the kernel bug (#20096) is fixed.
 	if plugin.hairpinMode == kubeletconfig.PromiscuousBridge {
@@ -348,57 +393,97 @@ func (plugin *kubenetNetworkPlugin) setup(namespace string, name string, id kube
 		plugin.syncEbtablesDedupRules(link.Attrs().HardwareAddr)
 	}
 
-	plugin.podIPs[id] = ip4.String()
+	// add the ip to tracked ips
+	if ipv4 != nil {
+		plugin.addPodIP(id, ipv4.String())
+	}
+	if ipv6 != nil {
+		plugin.addPodIP(id, ipv6.String())
+	}
 
-	// The first SetUpPod call creates the bridge; get a shaper for the sake of initialization
-	// TODO: replace with CNI traffic shaper plugin
+	if err := plugin.addTrafficShaping(id, annotations); err != nil {
+		return err
+	}
+
+	return plugin.addPortMapping(id, name, namespace)
+}
+
+// The first SetUpPod call creates the bridge; get a shaper for the sake of initialization
+// TODO: replace with CNI traffic shaper plugin
+func (plugin *kubenetNetworkPlugin) addTrafficShaping(id kubecontainer.ContainerID, annotations map[string]string) error {
 	shaper := plugin.shaper()
 	ingress, egress, err := bandwidth.ExtractPodBandwidthResources(annotations)
 	if err != nil {
 		return fmt.Errorf("Error reading pod bandwidth annotations: %v", err)
 	}
-	if egress != nil || ingress != nil {
-		if err := shaper.ReconcileCIDR(fmt.Sprintf("%s/32", ip4.String()), egress, ingress); err != nil {
-			return fmt.Errorf("Failed to add pod to shaper: %v", err)
-		}
+	iplist, exists := plugin.getCachedPodIPs(id)
+	if !exists {
+		return fmt.Errorf("pod %s does not have recorded ips", id)
 	}
 
-	// TODO: replace with CNI port-forwarding plugin
-	portMappings, err := plugin.host.GetPodPortMappings(id.ID)
-	if err != nil {
-		return err
-	}
-	if portMappings != nil && len(portMappings) > 0 {
-		if err := plugin.hostportManager.Add(id.ID, &hostport.PodPortMapping{
-			Namespace:    namespace,
-			Name:         name,
-			PortMappings: portMappings,
-			IP:           ip4,
-			HostNetwork:  false,
-		}, BridgeName); err != nil {
-			return err
+	if egress != nil || ingress != nil {
+		for _, ip := range iplist {
+			mask := 32
+			if netutils.IsIPv6String(ip) {
+				mask = 128
+			}
+			if err != nil {
+				return fmt.Errorf("failed to setup traffic shaping for pod ip%s", ip)
+			}
+
+			if err := shaper.ReconcileCIDR(fmt.Sprintf("%v/%v", ip, mask), egress, ingress); err != nil {
+				return fmt.Errorf("Failed to add pod to shaper: %v", err)
+			}
 		}
 	}
 	return nil
 }
 
-func (plugin *kubenetNetworkPlugin) SetUpPod(namespace string, name string, id kubecontainer.ContainerID, annotations, options map[string]string) error {
-	plugin.mu.Lock()
-	defer plugin.mu.Unlock()
+// TODO: replace with CNI port-forwarding plugin
+func (plugin *kubenetNetworkPlugin) addPortMapping(id kubecontainer.ContainerID, name, namespace string) error {
+	portMappings, err := plugin.host.GetPodPortMappings(id.ID)
+	if err != nil {
+		return err
+	}
 
+	if len(portMappings) == 0 {
+		return nil
+	}
+
+	iplist, exists := plugin.getCachedPodIPs(id)
+	if !exists {
+		return fmt.Errorf("pod %s does not have recorded ips", id)
+	}
+
+	for _, ip := range iplist {
+		pm := &hostport.PodPortMapping{
+			Namespace:    namespace,
+			Name:         name,
+			PortMappings: portMappings,
+			IP:           net.ParseIP(ip),
+			HostNetwork:  false,
+		}
+		if err := plugin.hostportManager.Add(id.ID, pm, BridgeName); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (plugin *kubenetNetworkPlugin) SetUpPod(namespace string, name string, id kubecontainer.ContainerID, annotations, options map[string]string) error {
 	start := time.Now()
-	defer func() {
-		klog.V(4).Infof("SetUpPod took %v for %s/%s", time.Since(start), namespace, name)
-	}()
 
 	if err := plugin.Status(); err != nil {
 		return fmt.Errorf("Kubenet cannot SetUpPod: %v", err)
 	}
 
+	defer func() {
+		klog.V(4).Infof("SetUpPod took %v for %s/%s", time.Since(start), namespace, name)
+	}()
+
 	if err := plugin.setup(namespace, name, id, annotations); err != nil {
-		// Make sure everything gets cleaned up on errors
-		podIP, _ := plugin.podIPs[id]
-		if err := plugin.teardown(namespace, name, id, podIP); err != nil {
+		if err := plugin.teardown(namespace, name, id); err != nil {
 			// Not a hard error or warning
 			klog.V(4).Infof("Failed to clean up %s/%s after SetUpPod failure: %v", namespace, name, err)
 		}
@@ -415,27 +500,12 @@ func (plugin *kubenetNetworkPlugin) SetUpPod(namespace string, name string, id k
 
 // Tears down as much of a pod's network as it can even if errors occur.  Returns
 // an aggregate error composed of all errors encountered during the teardown.
-func (plugin *kubenetNetworkPlugin) teardown(namespace string, name string, id kubecontainer.ContainerID, podIP string) error {
+func (plugin *kubenetNetworkPlugin) teardown(namespace string, name string, id kubecontainer.ContainerID) error {
 	errList := []error{}
 
-	if podIP != "" {
-		klog.V(5).Infof("Removing pod IP %s from shaper", podIP)
-		// shaper wants /32
-		if err := plugin.shaper().Reset(fmt.Sprintf("%s/32", podIP)); err != nil {
-			// Possible bandwidth shaping wasn't enabled for this pod anyways
-			klog.V(4).Infof("Failed to remove pod IP %s from shaper: %v", podIP, err)
-		}
-
-		delete(plugin.podIPs, id)
-	}
-
+	// no ip dependent actions
 	if err := plugin.delContainerFromNetwork(plugin.netConfig, network.DefaultInterfaceName, namespace, name, id); err != nil {
-		// This is to prevent returning error when TearDownPod is called twice on the same pod. This helps to reduce event pollution.
-		if podIP != "" {
-			klog.Warningf("Failed to delete container from kubenet: %v", err)
-		} else {
-			errList = append(errList, err)
-		}
+		errList = append(errList, err)
 	}
 
 	portMappings, err := plugin.host.GetPodPortMappings(id.ID)
@@ -451,13 +521,33 @@ func (plugin *kubenetNetworkPlugin) teardown(namespace string, name string, id k
 			errList = append(errList, err)
 		}
 	}
+
+	iplist, exists := plugin.getCachedPodIPs(id)
+	if !exists || len(iplist) == 0 {
+		klog.V(5).Infof("container %s (%s/%s) does not have recorded. ignoring teardown call", id, name, namespace)
+		return nil
+	}
+
+	for _, ip := range iplist {
+		klog.V(5).Infof("Removing pod IP %s from shaper for (%s/%s)", ip, name, namespace)
+		// shaper uses a cidr, but we are using a single IP.
+		isV6 := netutils.IsIPv6String(ip)
+		mask := "32"
+		if isV6 {
+			mask = "128"
+		}
+
+		if err := plugin.shaper().Reset(fmt.Sprintf("%s/%s", ip, mask)); err != nil {
+			// Possible bandwidth shaping wasn't enabled for this pod anyways
+			klog.V(4).Infof("Failed to remove pod IP %s from shaper: %v", ip, err)
+		}
+
+		plugin.removePodIP(id, ip)
+	}
 	return utilerrors.NewAggregate(errList)
 }
 
 func (plugin *kubenetNetworkPlugin) TearDownPod(namespace string, name string, id kubecontainer.ContainerID) error {
-	plugin.mu.Lock()
-	defer plugin.mu.Unlock()
-
 	start := time.Now()
 	defer func() {
 		klog.V(4).Infof("TearDownPod took %v for %s/%s", time.Since(start), namespace, name)
@@ -467,9 +557,7 @@ func (plugin *kubenetNetworkPlugin) TearDownPod(namespace string, name string, i
 		return fmt.Errorf("Kubenet needs a PodCIDR to tear down pods")
 	}
 
-	// no cached IP is Ok during teardown
-	podIP, _ := plugin.podIPs[id]
-	if err := plugin.teardown(namespace, name, id, podIP); err != nil {
+	if err := plugin.teardown(namespace, name, id); err != nil {
 		return err
 	}
 
@@ -477,20 +565,19 @@ func (plugin *kubenetNetworkPlugin) TearDownPod(namespace string, name string, i
 	if err := plugin.ensureMasqRule(); err != nil {
 		klog.Errorf("Failed to ensure MASQ rule: %v", err)
 	}
-
 	return nil
 }
 
 // TODO: Use the addToNetwork function to obtain the IP of the Pod. That will assume idempotent ADD call to the plugin.
 // Also fix the runtime's call to Status function to be done only in the case that the IP is lost, no need to do periodic calls
 func (plugin *kubenetNetworkPlugin) GetPodNetworkStatus(namespace string, name string, id kubecontainer.ContainerID) (*network.PodNetworkStatus, error) {
-	plugin.mu.Lock()
-	defer plugin.mu.Unlock()
-	// Assuming the ip of pod does not change. Try to retrieve ip from kubenet map first.
-	if podIP, ok := plugin.podIPs[id]; ok {
-		return &network.PodNetworkStatus{IP: net.ParseIP(podIP)}, nil
+	// try cached version
+	networkStatus := plugin.getNetworkStatus(id)
+	if networkStatus != nil {
+		return networkStatus, nil
 	}
 
+	// not a cached version, get via network ns
 	netnsPath, err := plugin.host.GetNetNS(id.ID)
 	if err != nil {
 		return nil, fmt.Errorf("Kubenet failed to retrieve network namespace path: %v", err)
@@ -498,13 +585,46 @@ func (plugin *kubenetNetworkPlugin) GetPodNetworkStatus(namespace string, name s
 	if netnsPath == "" {
 		return nil, fmt.Errorf("Cannot find the network namespace, skipping pod network status for container %q", id)
 	}
-	ip, err := network.GetPodIP(plugin.execer, plugin.nsenterPath, netnsPath, network.DefaultInterfaceName)
+	ips, err := network.GetPodIPs(plugin.execer, plugin.nsenterPath, netnsPath, network.DefaultInterfaceName)
 	if err != nil {
 		return nil, err
 	}
 
-	plugin.podIPs[id] = ip.String()
-	return &network.PodNetworkStatus{IP: ip}, nil
+	// cache the ips
+	for _, ip := range ips {
+		plugin.addPodIP(id, ip.String())
+	}
+
+	// return from cached
+	return plugin.getNetworkStatus(id), nil
+}
+
+// returns networkstatus
+func (plugin *kubenetNetworkPlugin) getNetworkStatus(id kubecontainer.ContainerID) *network.PodNetworkStatus {
+	// Assuming the ip of pod does not change. Try to retrieve ip from kubenet map first.
+	iplist, ok := plugin.getCachedPodIPs(id)
+	if !ok {
+		return nil
+	}
+	// sort making v4 first
+	// TODO: (khenidak) IPv6 beta stage.
+	// This - forced sort - could be avoided by checking which cidr that an IP belongs
+	// to, then placing the IP according to cidr index. But before doing that. Check how IP is collected
+	// across all of kubelet code (against cni and cri).
+	ips := make([]net.IP, 0)
+	for _, ip := range iplist {
+		isV6 := netutils.IsIPv6String(ip)
+		if !isV6 {
+			ips = append([]net.IP{net.ParseIP(ip)}, ips...)
+		} else {
+			ips = append(ips, net.ParseIP(ip))
+		}
+	}
+
+	return &network.PodNetworkStatus{
+		IP:  ips[0],
+		IPs: ips,
+	}
 }
 
 func (plugin *kubenetNetworkPlugin) Status() error {
@@ -571,11 +691,8 @@ func (plugin *kubenetNetworkPlugin) addContainerToNetwork(config *libcni.Network
 	}
 
 	klog.V(3).Infof("Adding %s/%s to '%s' with CNI '%s' plugin and runtime: %+v", namespace, name, config.Network.Name, config.Network.Type, rt)
-	// The network plugin can take up to 3 seconds to execute,
-	// so yield the lock while it runs.
-	plugin.mu.Unlock()
+
 	res, err := plugin.cniConfig.AddNetwork(context.TODO(), config, rt)
-	plugin.mu.Lock()
 	if err != nil {
 		return nil, fmt.Errorf("Error adding container to network: %v", err)
 	}
@@ -600,8 +717,9 @@ func (plugin *kubenetNetworkPlugin) delContainerFromNetwork(config *libcni.Netwo
 
 // shaper retrieves the bandwidth shaper and, if it hasn't been fetched before,
 // initializes it and ensures the bridge is appropriately configured
-// This function should only be called while holding the `plugin.mu` lock
 func (plugin *kubenetNetworkPlugin) shaper() bandwidth.Shaper {
+	plugin.mu.Lock()
+	defer plugin.mu.Unlock()
 	if plugin.bandwidthShaper == nil {
 		plugin.bandwidthShaper = bandwidth.NewTCShaper(BridgeName)
 		plugin.bandwidthShaper.ReconcileInterface()
@@ -624,30 +742,43 @@ func (plugin *kubenetNetworkPlugin) syncEbtablesDedupRules(macAddr net.HardwareA
 		return
 	}
 
-	klog.V(3).Infof("Filtering packets with ebtables on mac address: %v, gateway: %v, pod CIDR: %v", macAddr.String(), plugin.gateway.String(), plugin.podCidr)
+	// ensure custom chain exists
 	_, err = plugin.ebtables.EnsureChain(utilebtables.TableFilter, dedupChain)
 	if err != nil {
 		klog.Errorf("Failed to ensure %v chain %v", utilebtables.TableFilter, dedupChain)
 		return
 	}
 
+	// jump to custom chain to the chain from core tables
 	_, err = plugin.ebtables.EnsureRule(utilebtables.Append, utilebtables.TableFilter, utilebtables.ChainOutput, "-j", string(dedupChain))
 	if err != nil {
 		klog.Errorf("Failed to ensure %v chain %v jump to %v chain: %v", utilebtables.TableFilter, utilebtables.ChainOutput, dedupChain, err)
 		return
 	}
 
-	commonArgs := []string{"-p", "IPv4", "-s", macAddr.String(), "-o", "veth+"}
-	_, err = plugin.ebtables.EnsureRule(utilebtables.Prepend, utilebtables.TableFilter, dedupChain, append(commonArgs, "--ip-src", plugin.gateway.String(), "-j", "ACCEPT")...)
-	if err != nil {
-		klog.Errorf("Failed to ensure packets from cbr0 gateway to be accepted")
-		return
+	// per gateway rule
+	for idx, gw := range plugin.podGateways {
+		klog.V(3).Infof("Filtering packets with ebtables on mac address: %v, gateway: %v, pod CIDR: %v", macAddr.String(), gw.String(), plugin.podCIDRs[idx].String())
 
-	}
-	_, err = plugin.ebtables.EnsureRule(utilebtables.Append, utilebtables.TableFilter, dedupChain, append(commonArgs, "--ip-src", plugin.podCidr, "-j", "DROP")...)
-	if err != nil {
-		klog.Errorf("Failed to ensure packets from podCidr but has mac address of cbr0 to get dropped.")
-		return
+		bIsV6 := netutils.IsIPv6(gw)
+		IPFamily := "IPv4"
+		ipSrc := "--ip-src"
+		if bIsV6 {
+			IPFamily = "IPv6"
+			ipSrc = "--ip6-src"
+		}
+		commonArgs := []string{"-p", IPFamily, "-s", macAddr.String(), "-o", "veth+"}
+		_, err = plugin.ebtables.EnsureRule(utilebtables.Prepend, utilebtables.TableFilter, dedupChain, append(commonArgs, ipSrc, gw.String(), "-j", "ACCEPT")...)
+		if err != nil {
+			klog.Errorf("Failed to ensure packets from cbr0 gateway:%v to be accepted with error:%v", gw.String(), err)
+			return
+
+		}
+		_, err = plugin.ebtables.EnsureRule(utilebtables.Append, utilebtables.TableFilter, dedupChain, append(commonArgs, ipSrc, plugin.podCIDRs[idx].String(), "-j", "DROP")...)
+		if err != nil {
+			klog.Errorf("Failed to ensure packets from podCidr[%v] but has mac address of cbr0 to get dropped. err:%v", plugin.podCIDRs[idx].String(), err)
+			return
+		}
 	}
 }
 
@@ -690,3 +821,71 @@ func (plugin *kubenetNetworkPlugin) disableContainerDAD(id kubecontainer.Contain
 	}
 	return nil
 }
+
+// given a n cidrs assigned to nodes,
+// create bridge configuration that conforms to them
+func (plugin *kubenetNetworkPlugin) getRangesConfig() string {
+	createRange := func(thisNet *net.IPNet) string {
+		template := `
+[{
+"subnet": "%s",
+"gateway": "%s"
+}]`
+		return fmt.Sprintf(template, thisNet.String(), thisNet.IP.String())
+	}
+
+	ranges := make([]string, len(plugin.podCIDRs))
+	for idx, thisCIDR := range plugin.podCIDRs {
+		ranges[idx] = createRange(thisCIDR)
+	}
+	//[{range}], [{range}]
+	// each range is a subnet and a gateway
+	return strings.Join(ranges[:], ",")
+}
+
+func (plugin *kubenetNetworkPlugin) addPodIP(id kubecontainer.ContainerID, ip string) {
+	plugin.mu.Lock()
+	defer plugin.mu.Unlock()
+
+	_, exist := plugin.podIPs[id]
+	if !exist {
+		plugin.podIPs[id] = utilsets.NewString()
+	}
+
+	if !plugin.podIPs[id].Has(ip) {
+		plugin.podIPs[id].Insert(ip)
+	}
+}
+
+func (plugin *kubenetNetworkPlugin) removePodIP(id kubecontainer.ContainerID, ip string) {
+	plugin.mu.Lock()
+	defer plugin.mu.Unlock()
+
+	_, exist := plugin.podIPs[id]
+	if !exist {
+		return // did we restart kubelet?
+	}
+
+	if plugin.podIPs[id].Has(ip) {
+		plugin.podIPs[id].Delete(ip)
+	}
+
+	// if there is no more ips here. let us delete
+	if plugin.podIPs[id].Len() == 0 {
+		delete(plugin.podIPs, id)
+	}
+}
+
+// returns a copy of pod ips
+// false is returned if id does not exist
+func (plugin *kubenetNetworkPlugin) getCachedPodIPs(id kubecontainer.ContainerID) ([]string, bool) {
+	plugin.mu.Lock()
+	defer plugin.mu.Unlock()
+
+	iplist, exists := plugin.podIPs[id]
+	if !exists {
+		return nil, false
+	}
+
+	return iplist.UnsortedList(), true
+}

pkg/kubelet/dockershim/network/kubenet/kubenet_linux_test.go

@@ -18,12 +18,13 @@ package kubenet
 
 import (
 	"fmt"
-
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
+	"strings"
 
 	"testing"
 
+	utilsets "k8s.io/apimachinery/pkg/util/sets"
 	kubeletconfig "k8s.io/kubernetes/pkg/kubelet/apis/config"
 	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
 	"k8s.io/kubernetes/pkg/kubelet/dockershim/network"
@@ -40,7 +41,7 @@ import (
 // test it fulfills the NetworkPlugin interface
 var _ network.NetworkPlugin = &kubenetNetworkPlugin{}
 
-func newFakeKubenetPlugin(initMap map[kubecontainer.ContainerID]string, execer exec.Interface, host network.Host) *kubenetNetworkPlugin {
+func newFakeKubenetPlugin(initMap map[kubecontainer.ContainerID]utilsets.String, execer exec.Interface, host network.Host) *kubenetNetworkPlugin {
 	return &kubenetNetworkPlugin{
 		podIPs: initMap,
 		execer: execer,
@@ -50,31 +51,38 @@ func newFakeKubenetPlugin(initMap map[kubecontainer.ContainerID]string, execer e
 }
 
 func TestGetPodNetworkStatus(t *testing.T) {
-	podIPMap := make(map[kubecontainer.ContainerID]string)
-	podIPMap[kubecontainer.ContainerID{ID: "1"}] = "10.245.0.2"
-	podIPMap[kubecontainer.ContainerID{ID: "2"}] = "10.245.0.3"
+	podIPMap := make(map[kubecontainer.ContainerID]utilsets.String)
+	podIPMap[kubecontainer.ContainerID{ID: "1"}] = utilsets.NewString("10.245.0.2")
+	podIPMap[kubecontainer.ContainerID{ID: "2"}] = utilsets.NewString("10.245.0.3")
+	podIPMap[kubecontainer.ContainerID{ID: "3"}] = utilsets.NewString("10.245.0.4", "2000::")
 
 	testCases := []struct {
 		id          string
 		expectError bool
-		expectIP    string
+		expectIP    utilsets.String
 	}{
 		//in podCIDR map
 		{
-			"1",
-			false,
-			"10.245.0.2",
+			id:          "1",
+			expectError: false,
+			expectIP:    utilsets.NewString("10.245.0.2"),
 		},
 		{
-			"2",
-			false,
-			"10.245.0.3",
+			id:          "2",
+			expectError: false,
+			expectIP:    utilsets.NewString("10.245.0.3"),
 		},
-		//not in podCIDR map
 		{
-			"3",
-			true,
-			"",
+			id:          "3",
+			expectError: false,
+			expectIP:    utilsets.NewString("10.245.0.4", "2000::"),
+		},
+
+		//not in podIP map
+		{
+			id:          "does-not-exist-map",
+			expectError: true,
+			expectIP:    nil,
 		},
 		//TODO: add test cases for retrieving ip inside container network namespace
 	}
@@ -85,11 +93,12 @@ func TestGetPodNetworkStatus(t *testing.T) {
 		fCmd := fakeexec.FakeCmd{
 			CombinedOutputScript: []fakeexec.FakeCombinedOutputAction{
 				func() ([]byte, error) {
-					ip, ok := podIPMap[kubecontainer.ContainerID{ID: t.id}]
+					ips, ok := podIPMap[kubecontainer.ContainerID{ID: t.id}]
 					if !ok {
 						return nil, fmt.Errorf("Pod IP %q not found", t.id)
 					}
-					return []byte(ip), nil
+					ipsList := ips.UnsortedList()
+					return []byte(ipsList[0]), nil
 				},
 			},
 		}
@@ -119,9 +128,20 @@ func TestGetPodNetworkStatus(t *testing.T) {
 				t.Errorf("Test case %d expects error but got error: %v", i, err)
 			}
 		}
-		if tc.expectIP != out.IP.String() {
+		seen := make(map[string]bool)
+		allExpected := tc.expectIP.UnsortedList()
+		for _, expectedIP := range allExpected {
+			for _, outIP := range out.IPs {
+				if expectedIP == outIP.String() {
+					seen[expectedIP] = true
+					break
+				}
+			}
+		}
+		if len(tc.expectIP) != len(seen) {
 			t.Errorf("Test case %d expects ip %s but got %s", i, tc.expectIP, out.IP.String())
 		}
+
 	}
 }
 
@@ -137,7 +157,8 @@ func TestTeardownCallsShaper(t *testing.T) {
 	fhost := nettest.NewFakeHost(nil)
 	fshaper := &bandwidth.FakeShaper{}
 	mockcni := &mock_cni.MockCNI{}
-	kubenet := newFakeKubenetPlugin(map[kubecontainer.ContainerID]string{}, fexec, fhost)
+	ips := make(map[kubecontainer.ContainerID]utilsets.String)
+	kubenet := newFakeKubenetPlugin(ips, fexec, fhost)
 	kubenet.cniConfig = mockcni
 	kubenet.iptables = ipttest.NewFake()
 	kubenet.bandwidthShaper = fshaper
@@ -150,7 +171,7 @@ func TestTeardownCallsShaper(t *testing.T) {
 	kubenet.Event(network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE, details)
 
 	existingContainerID := kubecontainer.BuildContainerID("docker", "123")
-	kubenet.podIPs[existingContainerID] = "10.0.0.1"
+	kubenet.podIPs[existingContainerID] = utilsets.NewString("10.0.0.1")
 
 	if err := kubenet.TearDownPod("namespace", "name", existingContainerID); err != nil {
 		t.Fatalf("Unexpected error in TearDownPod: %v", err)
@@ -185,7 +206,8 @@ func TestInit_MTU(t *testing.T) {
 	}
 
 	fhost := nettest.NewFakeHost(nil)
-	kubenet := newFakeKubenetPlugin(map[kubecontainer.ContainerID]string{}, fexec, fhost)
+	ips := make(map[kubecontainer.ContainerID]utilsets.String)
+	kubenet := newFakeKubenetPlugin(ips, fexec, fhost)
 	kubenet.iptables = ipttest.NewFake()
 
 	sysctl := sysctltest.NewFake()
@@ -203,22 +225,23 @@ func TestInit_MTU(t *testing.T) {
 // This is how kubenet is invoked from the cri.
 func TestTearDownWithoutRuntime(t *testing.T) {
 	testCases := []struct {
-		podCIDR         string
+		podCIDR         []string
 		ip              string
-		expectedGateway string
+		expectedGateway []string
 	}{
 		{
-			podCIDR:         "10.0.0.1/24",
+			podCIDR:         []string{"10.0.0.1/24"},
 			ip:              "10.0.0.1",
-			expectedGateway: "10.0.0.1",
+			expectedGateway: []string{"10.0.0.1"},
 		},
 		{
-			podCIDR:         "2001:beef::1/48",
+			podCIDR:         []string{"2001:beef::1/48"},
 			ip:              "2001:beef::1",
-			expectedGateway: "2001:beef::1",
+			expectedGateway: []string{"2001:beef::1"},
 		},
 	}
 	for _, tc := range testCases {
+
 		fhost := nettest.NewFakeHost(nil)
 		fhost.Legacy = false
 		mockcni := &mock_cni.MockCNI{}
@@ -230,22 +253,39 @@ func TestTearDownWithoutRuntime(t *testing.T) {
 			},
 		}
 
-		kubenet := newFakeKubenetPlugin(map[kubecontainer.ContainerID]string{}, fexec, fhost)
+		ips := make(map[kubecontainer.ContainerID]utilsets.String)
+		kubenet := newFakeKubenetPlugin(ips, fexec, fhost)
 		kubenet.cniConfig = mockcni
 		kubenet.iptables = ipttest.NewFake()
 
 		details := make(map[string]interface{})
-		details[network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE_DETAIL_CIDR] = tc.podCIDR
+		details[network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE_DETAIL_CIDR] = strings.Join(tc.podCIDR, ",")
 		kubenet.Event(network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE, details)
 
-		if kubenet.gateway.String() != tc.expectedGateway {
-			t.Errorf("generated gateway: %q, expecting: %q", kubenet.gateway.String(), tc.expectedGateway)
+		if len(kubenet.podGateways) != len(tc.expectedGateway) {
+			t.Errorf("generated gateway: %q, expecting: %q are not of the same length", kubenet.podGateways, tc.expectedGateway)
+			continue
 		}
-		if kubenet.podCidr != tc.podCIDR {
-			t.Errorf("generated podCidr: %q, expecting: %q", kubenet.podCidr, tc.podCIDR)
+
+		for idx := range tc.expectedGateway {
+			if kubenet.podGateways[idx].String() != tc.expectedGateway[idx] {
+				t.Errorf("generated gateway: %q, expecting: %q", kubenet.podGateways[idx].String(), tc.expectedGateway[idx])
+
+			}
 		}
+
+		if len(kubenet.podCIDRs) != len(tc.podCIDR) {
+			t.Errorf("generated podCidr: %q, expecting: %q are not of the same length", kubenet.podCIDRs, tc.podCIDR)
+			continue
+		}
+		for idx := range tc.podCIDR {
+			if kubenet.podCIDRs[idx].String() != tc.podCIDR[idx] {
+				t.Errorf("generated podCidr: %q, expecting: %q", kubenet.podCIDRs[idx].String(), tc.podCIDR[idx])
+			}
+		}
+
 		existingContainerID := kubecontainer.BuildContainerID("docker", "123")
-		kubenet.podIPs[existingContainerID] = tc.ip
+		kubenet.podIPs[existingContainerID] = utilsets.NewString(tc.ip)
 
 		mockcni.On("DelNetwork", mock.AnythingOfType("*context.emptyCtx"), mock.AnythingOfType("*libcni.NetworkConfig"), mock.AnythingOfType("*libcni.RuntimeConf")).Return(nil)
 

pkg/kubelet/dockershim/network/plugins.go

@@ -34,6 +34,9 @@ import (
 	"k8s.io/kubernetes/pkg/kubelet/dockershim/network/metrics"
 	utilsysctl "k8s.io/kubernetes/pkg/util/sysctl"
 	utilexec "k8s.io/utils/exec"
+
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	kubefeatures "k8s.io/kubernetes/pkg/features"
 )
 
 const (
@@ -89,6 +92,8 @@ type PodNetworkStatus struct {
 	//   - service endpoints are constructed with
 	//   - will be reported in the PodStatus.PodIP field (will override the IP reported by docker)
 	IP net.IP `json:"ip" description:"Primary IP address of the pod"`
+	// IPs is the list of IPs assigned to Pod. IPs[0] == IP. The rest of the list is additional IPs
+	IPs []net.IP `json:"ips" description:"list of additional ips (inclusive of IP) assigned to pod"`
 }
 
 // Host is an interface that plugins can use to access the kubelet.
@@ -250,17 +255,37 @@ func getOnePodIP(execer utilexec.Interface, nsenterPath, netnsPath, interfaceNam
 }
 
 // GetPodIP gets the IP of the pod by inspecting the network info inside the pod's network namespace.
-func GetPodIP(execer utilexec.Interface, nsenterPath, netnsPath, interfaceName string) (net.IP, error) {
-	ip, err := getOnePodIP(execer, nsenterPath, netnsPath, interfaceName, "-4")
-	if err != nil {
-		// Fall back to IPv6 address if no IPv4 address is present
-		ip, err = getOnePodIP(execer, nsenterPath, netnsPath, interfaceName, "-6")
-	}
-	if err != nil {
-		return nil, err
+// TODO (khenidak). The "primary ip" in dual stack world does not really exist. For now
+// we are defaulting to v4 as primary
+func GetPodIPs(execer utilexec.Interface, nsenterPath, netnsPath, interfaceName string) ([]net.IP, error) {
+	if !utilfeature.DefaultFeatureGate.Enabled(kubefeatures.IPv6DualStack) {
+		ip, err := getOnePodIP(execer, nsenterPath, netnsPath, interfaceName, "-4")
+		if err != nil {
+			// Fall back to IPv6 address if no IPv4 address is present
+			ip, err = getOnePodIP(execer, nsenterPath, netnsPath, interfaceName, "-6")
+		}
+		if err != nil {
+			return nil, err
+		}
+
+		return []net.IP{ip}, nil
 	}
 
-	return ip, nil
+	list := make([]net.IP, 0)
+	var err4, err6 error
+	if ipv4, err4 := getOnePodIP(execer, nsenterPath, netnsPath, interfaceName, "-4"); err4 != nil {
+		list = append(list, ipv4)
+	}
+
+	if ipv6, err6 := getOnePodIP(execer, nsenterPath, netnsPath, interfaceName, "-6"); err6 != nil {
+		list = append(list, ipv6)
+	}
+
+	if len(list) == 0 {
+		return nil, utilerrors.NewAggregate([]error{err4, err6})
+	}
+	return list, nil
+
 }
 
 type NoopPortMappingGetter struct{}

pkg/kubelet/kubelet.go

@@ -27,6 +27,7 @@ import (
 	"os"
 	"path"
 	"sort"
+	"strings"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -1520,8 +1521,10 @@ func (kl *Kubelet) syncPod(o syncPodOptions) error {
 	// The pod IP may be changed in generateAPIPodStatus if the pod is using host network. (See #24576)
 	// TODO(random-liu): After writing pod spec into container labels, check whether pod is using host network, and
 	// set pod IP to hostIP directly in runtime.GetPodStatus
-	podStatus.IP = apiPodStatus.PodIP
-
+	podStatus.IPs = make([]string, 0, len(apiPodStatus.PodIPs))
+	for _, ipInfo := range apiPodStatus.PodIPs {
+		podStatus.IPs = append(podStatus.IPs, ipInfo.IP)
+	}
 	// Record the time it takes for the pod to become running.
 	existingStatus, ok := kl.statusManager.GetPodStatus(pod.UID)
 	if !ok || existingStatus.Phase == v1.PodPending && apiPodStatus.Phase == v1.PodRunning &&
@@ -2250,9 +2253,10 @@ func (kl *Kubelet) fastStatusUpdateOnce() {
 			klog.Errorf(err.Error())
 			continue
 		}
-		if node.Spec.PodCIDR != "" {
-			if _, err := kl.updatePodCIDR(node.Spec.PodCIDR); err != nil {
-				klog.Errorf("Pod CIDR update failed %v", err)
+		if len(node.Spec.PodCIDRs) != 0 {
+			podCIDRs := strings.Join(node.Spec.PodCIDRs, ",")
+			if _, err := kl.updatePodCIDR(podCIDRs); err != nil {
+				klog.Errorf("Pod CIDR update to %v failed %v", podCIDRs, err)
 				continue
 			}
 			kl.updateRuntimeUp()

pkg/kubelet/kubelet_node_status.go

@@ -22,11 +22,10 @@ import (
 	"net"
 	goruntime "runtime"
 	"sort"
+	"strings"
 	"time"
 
-	"k8s.io/klog"
-
-	v1 "k8s.io/api/core/v1"
+	"k8s.io/api/core/v1"
 	apiequality "k8s.io/apimachinery/pkg/api/equality"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/resource"
@@ -34,6 +33,7 @@ import (
 	"k8s.io/apimachinery/pkg/types"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	cloudprovider "k8s.io/cloud-provider"
+	"k8s.io/klog"
 	k8s_api_v1 "k8s.io/kubernetes/pkg/apis/core/v1"
 	v1helper "k8s.io/kubernetes/pkg/apis/core/v1/helper"
 	"k8s.io/kubernetes/pkg/features"
@@ -417,11 +417,12 @@ func (kl *Kubelet) tryUpdateNodeStatus(tryNumber int) error {
 	}
 
 	podCIDRChanged := false
-	if node.Spec.PodCIDR != "" {
+	if len(node.Spec.PodCIDRs) != 0 {
 		// Pod CIDR could have been updated before, so we cannot rely on
 		// node.Spec.PodCIDR being non-empty. We also need to know if pod CIDR is
 		// actually changed.
-		if podCIDRChanged, err = kl.updatePodCIDR(node.Spec.PodCIDR); err != nil {
+		podCIDRs := strings.Join(node.Spec.PodCIDRs, ",")
+		if podCIDRChanged, err = kl.updatePodCIDR(podCIDRs); err != nil {
 			klog.Errorf(err.Error())
 		}
 	}

pkg/kubelet/kubelet_node_status_test.go

@@ -23,6 +23,7 @@ import (
 	goruntime "runtime"
 	"sort"
 	"strconv"
+	"strings"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -1004,11 +1005,12 @@ func TestUpdateNodeStatusWithLease(t *testing.T) {
 	// Report node status if it is still within the duration of nodeStatusReportFrequency.
 	clock.Step(10 * time.Second)
 	assert.Equal(t, "", kubelet.runtimeState.podCIDR(), "Pod CIDR should be empty")
-	podCIDR := "10.0.0.0/24"
-	updatedNode.Spec.PodCIDR = podCIDR
+	podCIDRs := []string{"10.0.0.0/24", "2000::/10"}
+	updatedNode.Spec.PodCIDR = podCIDRs[0]
+	updatedNode.Spec.PodCIDRs = podCIDRs
 	kubeClient.ReactionChain = fake.NewSimpleClientset(&v1.NodeList{Items: []v1.Node{*updatedNode}}).ReactionChain
 	assert.NoError(t, kubelet.updateNodeStatus())
-	assert.Equal(t, podCIDR, kubelet.runtimeState.podCIDR(), "Pod CIDR should be updated now")
+	assert.Equal(t, strings.Join(podCIDRs, ","), kubelet.runtimeState.podCIDR(), "Pod CIDR should be updated now")
 	// 2 more action (There were 7 actions before).
 	actions = kubeClient.Actions()
 	assert.Len(t, actions, 9)
@@ -1019,7 +1021,8 @@ func TestUpdateNodeStatusWithLease(t *testing.T) {
 	// Update node status when keeping the pod CIDR.
 	// Do not report node status if it is within the duration of nodeStatusReportFrequency.
 	clock.Step(10 * time.Second)
-	assert.Equal(t, podCIDR, kubelet.runtimeState.podCIDR(), "Pod CIDR should already be updated")
+	assert.Equal(t, strings.Join(podCIDRs, ","), kubelet.runtimeState.podCIDR(), "Pod CIDR should already be updated")
+
 	assert.NoError(t, kubelet.updateNodeStatus())
 	// Only 1 more action (There were 9 actions before).
 	actions = kubeClient.Actions()

pkg/kubelet/kubelet_pods.go

@@ -1382,7 +1382,16 @@ func (kl *Kubelet) generateAPIPodStatus(pod *v1.Pod, podStatus *kubecontainer.Po
 // alter the kubelet state at all.
 func (kl *Kubelet) convertStatusToAPIStatus(pod *v1.Pod, podStatus *kubecontainer.PodStatus) *v1.PodStatus {
 	var apiPodStatus v1.PodStatus
-	apiPodStatus.PodIP = podStatus.IP
+	apiPodStatus.PodIPs = make([]v1.PodIP, 0, len(podStatus.IPs))
+	for _, ip := range podStatus.IPs {
+		apiPodStatus.PodIPs = append(apiPodStatus.PodIPs, v1.PodIP{
+			IP: ip,
+		})
+	}
+
+	if len(apiPodStatus.PodIPs) > 0 {
+		apiPodStatus.PodIP = apiPodStatus.PodIPs[0].IP
+	}
 	// set status for Pods created on versions of kube older than 1.6
 	apiPodStatus.QOSClass = v1qos.GetPodQOS(pod)
 

pkg/kubelet/kuberuntime/kuberuntime_manager.go

@@ -663,18 +663,18 @@ func (m *kubeGenericRuntimeManager) SyncPod(pod *v1.Pod, podStatus *kubecontaine
 	// by container garbage collector.
 	m.pruneInitContainersBeforeStart(pod, podStatus)
 
-	// We pass the value of the podIP down to generatePodSandboxConfig and
+	// We pass the value of the PRIMARY podIP down to generatePodSandboxConfig and
 	// generateContainerConfig, which in turn passes it to various other
 	// functions, in order to facilitate functionality that requires this
 	// value (hosts file and downward API) and avoid races determining
 	// the pod IP in cases where a container requires restart but the
 	// podIP isn't in the status manager yet.
 	//
-	// We default to the IP in the passed-in pod status, and overwrite it if the
+	// We default to the IPs in the passed-in pod status, and overwrite them if the
 	// sandbox needs to be (re)started.
-	podIP := ""
+	var podIPs []string
 	if podStatus != nil {
-		podIP = podStatus.IP
+		podIPs = podStatus.IPs
 	}
 
 	// Step 4: Create a sandbox for the pod if necessary.
@@ -714,12 +714,20 @@ func (m *kubeGenericRuntimeManager) SyncPod(pod *v1.Pod, podStatus *kubecontaine
 		// If we ever allow updating a pod from non-host-network to
 		// host-network, we may use a stale IP.
 		if !kubecontainer.IsHostNetworkPod(pod) {
-			// Overwrite the podIP passed in the pod status, since we just started the pod sandbox.
-			podIP = m.determinePodSandboxIP(pod.Namespace, pod.Name, podSandboxStatus)
-			klog.V(4).Infof("Determined the ip %q for pod %q after sandbox changed", podIP, format.Pod(pod))
+			// Overwrite the podIPs passed in the pod status, since we just started the pod sandbox.
+			podIPs = m.determinePodSandboxIPs(pod.Namespace, pod.Name, podSandboxStatus)
+			klog.V(4).Infof("Determined the ip %v for pod %q after sandbox changed", podIPs, format.Pod(pod))
 		}
 	}
 
+	// the start containers routines depend on pod ip(as in primary pod ip)
+	// instead of trying to figure out if we have 0 < len(podIPs)
+	// everytime, we short circuit it here
+	podIP := ""
+	if len(podIPs) != 0 {
+		podIP = podIPs[0]
+	}
+
 	// Get podSandboxConfig for containers to start.
 	configPodSandboxResult := kubecontainer.NewSyncResult(kubecontainer.ConfigPodSandbox, podSandboxID)
 	result.AddSyncResult(configPodSandboxResult)
@@ -880,7 +888,7 @@ func (m *kubeGenericRuntimeManager) GetPodStatus(uid kubetypes.UID, name, namesp
 	klog.V(4).Infof("getSandboxIDByPodUID got sandbox IDs %q for pod %q", podSandboxIDs, podFullName)
 
 	sandboxStatuses := make([]*runtimeapi.PodSandboxStatus, len(podSandboxIDs))
-	podIP := ""
+	podIPs := []string{}
 	for idx, podSandboxID := range podSandboxIDs {
 		podSandboxStatus, err := m.runtimeService.PodSandboxStatus(podSandboxID)
 		if err != nil {
@@ -891,7 +899,7 @@ func (m *kubeGenericRuntimeManager) GetPodStatus(uid kubetypes.UID, name, namesp
 
 		// Only get pod IP from latest sandbox
 		if idx == 0 && podSandboxStatus.State == runtimeapi.PodSandboxState_SANDBOX_READY {
-			podIP = m.determinePodSandboxIP(namespace, name, podSandboxStatus)
+			podIPs = m.determinePodSandboxIPs(namespace, name, podSandboxStatus)
 		}
 	}
 
@@ -909,7 +917,7 @@ func (m *kubeGenericRuntimeManager) GetPodStatus(uid kubetypes.UID, name, namesp
 		ID:                uid,
 		Name:              name,
 		Namespace:         namespace,
-		IP:                podIP,
+		IPs:               podIPs,
 		SandboxStatuses:   sandboxStatuses,
 		ContainerStatuses: containerStatuses,
 	}, nil

pkg/kubelet/kuberuntime/kuberuntime_manager_test.go

@@ -114,18 +114,29 @@ func makeFakePodSandbox(t *testing.T, m *kubeGenericRuntimeManager, template san
 	assert.NoError(t, err, "generatePodSandboxConfig for sandbox template %+v", template)
 
 	podSandboxID := apitest.BuildSandboxName(config.Metadata)
-	return &apitest.FakePodSandbox{
+	podSandBoxStatus := &apitest.FakePodSandbox{
 		PodSandboxStatus: runtimeapi.PodSandboxStatus{
 			Id:        podSandboxID,
 			Metadata:  config.Metadata,
 			State:     template.state,
 			CreatedAt: template.createdAt,
 			Network: &runtimeapi.PodSandboxNetworkStatus{
-				Ip: apitest.FakePodSandboxIP,
+				Ip: apitest.FakePodSandboxIPs[0],
 			},
 			Labels: config.Labels,
 		},
 	}
+	// assign additional IPs
+	additionalIPs := apitest.FakePodSandboxIPs[1:]
+	additionalPodIPs := make([]*runtimeapi.PodIP, 0, len(additionalIPs))
+	for _, ip := range additionalIPs {
+		additionalPodIPs = append(additionalPodIPs, &runtimeapi.PodIP{
+			Ip: ip,
+		})
+	}
+	podSandBoxStatus.Network.AdditionalIps = additionalPodIPs
+	return podSandBoxStatus
+
 }
 
 // makeFakePodSandboxes creates a group of fake pod sandboxes based on the sandbox templates.
@@ -311,7 +322,7 @@ func TestGetPodStatus(t *testing.T) {
 	assert.Equal(t, pod.UID, podStatus.ID)
 	assert.Equal(t, pod.Name, podStatus.Name)
 	assert.Equal(t, pod.Namespace, podStatus.Namespace)
-	assert.Equal(t, apitest.FakePodSandboxIP, podStatus.IP)
+	assert.Equal(t, apitest.FakePodSandboxIPs, podStatus.IPs)
 }
 
 func TestGetPods(t *testing.T) {

pkg/kubelet/kuberuntime/kuberuntime_sandbox.go

@@ -214,20 +214,36 @@ func (m *kubeGenericRuntimeManager) getKubeletSandboxes(all bool) ([]*runtimeapi
 	return resp, nil
 }
 
-// determinePodSandboxIP determines the IP address of the given pod sandbox.
-func (m *kubeGenericRuntimeManager) determinePodSandboxIP(podNamespace, podName string, podSandbox *runtimeapi.PodSandboxStatus) string {
+// determinePodSandboxIP determines the IP addresses of the given pod sandbox.
+func (m *kubeGenericRuntimeManager) determinePodSandboxIPs(podNamespace, podName string, podSandbox *runtimeapi.PodSandboxStatus) []string {
+	podIPs := make([]string, 0)
 	if podSandbox.Network == nil {
-		klog.Warningf("Pod Sandbox status doesn't have network information, cannot report IP")
-		return ""
+		klog.Warningf("Pod Sandbox status doesn't have network information, cannot report IPs")
+		return podIPs
 	}
-	ip := podSandbox.Network.Ip
-	if len(ip) != 0 && net.ParseIP(ip) == nil {
-		// ip could be an empty string if runtime is not responsible for the
-		// IP (e.g., host networking).
-		klog.Warningf("Pod Sandbox reported an unparseable IP %v", ip)
-		return ""
+
+	// ip could be an empty string if runtime is not responsible for the
+	// IP (e.g., host networking).
+
+	// pick primary IP
+	if len(podSandbox.Network.Ip) != 0 {
+		if net.ParseIP(podSandbox.Network.Ip) == nil {
+			klog.Warningf("Pod Sandbox reported an unparseable IP (Primary) %v", podSandbox.Network.Ip)
+			return nil
+		}
+		podIPs = append(podIPs, podSandbox.Network.Ip)
 	}
-	return ip
+
+	// pick additional ips, if cri reported them
+	for _, podIP := range podSandbox.Network.AdditionalIps {
+		if nil == net.ParseIP(podIP.Ip) {
+			klog.Warningf("Pod Sandbox reported an unparseable IP (additional) %v", podIP.Ip)
+			return nil
+		}
+		podIPs = append(podIPs, podIP.Ip)
+	}
+
+	return podIPs
 }
 
 // getPodSandboxID gets the sandbox id by podUID and returns ([]sandboxID, error).

pkg/kubelet/lifecycle/handlers.go

@@ -108,10 +108,10 @@ func (hr *HandlerRunner) runHTTPHandler(pod *v1.Pod, container *v1.Container, ha
 			klog.Errorf("Unable to get pod info, event handlers may be invalid.")
 			return "", err
 		}
-		if status.IP == "" {
+		if len(status.IPs) == 0 {
 			return "", fmt.Errorf("failed to find networking container: %v", status)
 		}
-		host = status.IP
+		host = status.IPs[0]
 	}
 	var port int
 	if handler.HTTPGet.Port.Type == intstr.String && len(handler.HTTPGet.Port.StrVal) == 0 {

pkg/kubelet/pleg/generic.go

@@ -344,22 +344,22 @@ func (g *GenericPLEG) cacheEnabled() bool {
 	return g.cache != nil
 }
 
-// getPodIP preserves an older cached status' pod IP if the new status has no pod IP
+// getPodIP preserves an older cached status' pod IP if the new status has no pod IPs
 // and its sandboxes have exited
-func (g *GenericPLEG) getPodIP(pid types.UID, status *kubecontainer.PodStatus) string {
-	if status.IP != "" {
-		return status.IP
+func (g *GenericPLEG) getPodIPs(pid types.UID, status *kubecontainer.PodStatus) []string {
+	if len(status.IPs) != 0 {
+		return status.IPs
 	}
 
 	oldStatus, err := g.cache.Get(pid)
-	if err != nil || oldStatus.IP == "" {
-		return ""
+	if err != nil || len(oldStatus.IPs) == 0 {
+		return nil
 	}
 
 	for _, sandboxStatus := range status.SandboxStatuses {
 		// If at least one sandbox is ready, then use this status update's pod IP
 		if sandboxStatus.State == runtimeapi.PodSandboxState_SANDBOX_READY {
-			return status.IP
+			return status.IPs
 		}
 	}
 
@@ -369,14 +369,14 @@ func (g *GenericPLEG) getPodIP(pid types.UID, status *kubecontainer.PodStatus) s
 		// running then use the new pod IP
 		for _, containerStatus := range status.ContainerStatuses {
 			if containerStatus.State == kubecontainer.ContainerStateCreated || containerStatus.State == kubecontainer.ContainerStateRunning {
-				return status.IP
+				return status.IPs
 			}
 		}
 	}
 
 	// For pods with no ready containers or sandboxes (like exited pods)
 	// use the old status' pod IP
-	return oldStatus.IP
+	return oldStatus.IPs
 }
 
 func (g *GenericPLEG) updateCache(pod *kubecontainer.Pod, pid types.UID) error {
@@ -398,7 +398,7 @@ func (g *GenericPLEG) updateCache(pod *kubecontainer.Pod, pid types.UID) error {
 		// When a pod is torn down, kubelet may race with PLEG and retrieve
 		// a pod status after network teardown, but the kubernetes API expects
 		// the completed pod's IP to be available after the pod is dead.
-		status.IP = g.getPodIP(pid, status)
+		status.IPs = g.getPodIPs(pid, status)
 	}
 
 	g.cache.Set(pod.ID, status, err, timestamp)

pkg/kubelet/pleg/generic_test.go

@@ -573,56 +573,73 @@ func TestRelistingWithSandboxes(t *testing.T) {
 }
 
 func TestRelistIPChange(t *testing.T) {
-	pleg, runtimeMock := newTestGenericPLEGWithRuntimeMock()
-	ch := pleg.Watch()
-
-	id := types.UID("test-pod-0")
-	cState := kubecontainer.ContainerStateRunning
-	container := createTestContainer("c0", cState)
-	pod := &kubecontainer.Pod{
-		ID:         id,
-		Containers: []*kubecontainer.Container{container},
+	testCases := []struct {
+		name   string
+		podID  string
+		podIPs []string
+	}{
+		{
+			name:   "test-0",
+			podID:  "test-pod-0",
+			podIPs: []string{"192.168.1.5"},
+		},
+		{
+			name:   "tets-1",
+			podID:  "test-pod-1",
+			podIPs: []string{"192.168.1.5/24", "2000::"},
+		},
 	}
-	ipAddr := "192.168.1.5/24"
-	status := &kubecontainer.PodStatus{
-		ID:                id,
-		IP:                ipAddr,
-		ContainerStatuses: []*kubecontainer.ContainerStatus{{ID: container.ID, State: cState}},
+	for _, tc := range testCases {
+		pleg, runtimeMock := newTestGenericPLEGWithRuntimeMock()
+		ch := pleg.Watch()
+
+		id := types.UID(tc.podID)
+		cState := kubecontainer.ContainerStateRunning
+		container := createTestContainer("c0", cState)
+		pod := &kubecontainer.Pod{
+			ID:         id,
+			Containers: []*kubecontainer.Container{container},
+		}
+		status := &kubecontainer.PodStatus{
+			ID:                id,
+			IPs:               tc.podIPs,
+			ContainerStatuses: []*kubecontainer.ContainerStatus{{ID: container.ID, State: cState}},
+		}
+		event := &PodLifecycleEvent{ID: pod.ID, Type: ContainerStarted, Data: container.ID.ID}
+
+		runtimeMock.On("GetPods", true).Return([]*kubecontainer.Pod{pod}, nil).Once()
+		runtimeMock.On("GetPodStatus", pod.ID, "", "").Return(status, nil).Once()
+
+		pleg.relist()
+		actualEvents := getEventsFromChannel(ch)
+		actualStatus, actualErr := pleg.cache.Get(pod.ID)
+		assert.Equal(t, status, actualStatus, tc.name)
+		assert.Nil(t, actualErr, tc.name)
+		assert.Exactly(t, []*PodLifecycleEvent{event}, actualEvents)
+
+		// Clear the IP address and mark the container terminated
+		container = createTestContainer("c0", kubecontainer.ContainerStateExited)
+		pod = &kubecontainer.Pod{
+			ID:         id,
+			Containers: []*kubecontainer.Container{container},
+		}
+		status = &kubecontainer.PodStatus{
+			ID:                id,
+			ContainerStatuses: []*kubecontainer.ContainerStatus{{ID: container.ID, State: kubecontainer.ContainerStateExited}},
+		}
+		event = &PodLifecycleEvent{ID: pod.ID, Type: ContainerDied, Data: container.ID.ID}
+		runtimeMock.On("GetPods", true).Return([]*kubecontainer.Pod{pod}, nil).Once()
+		runtimeMock.On("GetPodStatus", pod.ID, "", "").Return(status, nil).Once()
+
+		pleg.relist()
+		actualEvents = getEventsFromChannel(ch)
+		actualStatus, actualErr = pleg.cache.Get(pod.ID)
+		// Must copy status to compare since its pointer gets passed through all
+		// the way to the event
+		statusCopy := *status
+		statusCopy.IPs = tc.podIPs
+		assert.Equal(t, &statusCopy, actualStatus, tc.name)
+		assert.Nil(t, actualErr, tc.name)
+		assert.Exactly(t, []*PodLifecycleEvent{event}, actualEvents)
 	}
-	event := &PodLifecycleEvent{ID: pod.ID, Type: ContainerStarted, Data: container.ID.ID}
-
-	runtimeMock.On("GetPods", true).Return([]*kubecontainer.Pod{pod}, nil).Once()
-	runtimeMock.On("GetPodStatus", pod.ID, "", "").Return(status, nil).Once()
-
-	pleg.relist()
-	actualEvents := getEventsFromChannel(ch)
-	actualStatus, actualErr := pleg.cache.Get(pod.ID)
-	assert.Equal(t, status, actualStatus, "test0")
-	assert.Nil(t, actualErr, "test0")
-	assert.Exactly(t, []*PodLifecycleEvent{event}, actualEvents)
-
-	// Clear the IP address and mark the container terminated
-	container = createTestContainer("c0", kubecontainer.ContainerStateExited)
-	pod = &kubecontainer.Pod{
-		ID:         id,
-		Containers: []*kubecontainer.Container{container},
-	}
-	status = &kubecontainer.PodStatus{
-		ID:                id,
-		ContainerStatuses: []*kubecontainer.ContainerStatus{{ID: container.ID, State: kubecontainer.ContainerStateExited}},
-	}
-	event = &PodLifecycleEvent{ID: pod.ID, Type: ContainerDied, Data: container.ID.ID}
-	runtimeMock.On("GetPods", true).Return([]*kubecontainer.Pod{pod}, nil).Once()
-	runtimeMock.On("GetPodStatus", pod.ID, "", "").Return(status, nil).Once()
-
-	pleg.relist()
-	actualEvents = getEventsFromChannel(ch)
-	actualStatus, actualErr = pleg.cache.Get(pod.ID)
-	// Must copy status to compare since its pointer gets passed through all
-	// the way to the event
-	statusCopy := *status
-	statusCopy.IP = ipAddr
-	assert.Equal(t, &statusCopy, actualStatus, "test0")
-	assert.Nil(t, actualErr, "test0")
-	assert.Exactly(t, []*PodLifecycleEvent{event}, actualEvents)
 }

pkg/util/node/node.go

@@ -175,7 +175,7 @@ func PatchNodeCIDR(c clientset.Interface, node types.NodeName, cidr string) erro
 	return nil
 }
 
-// PatchNodeCIDR patches the specified node's CIDR to the given value.
+// PatchNodeCIDRs patches the specified node.CIDR=cidrs[0] and node.CIDRs to the given value.
 func PatchNodeCIDRs(c clientset.Interface, node types.NodeName, cidrs []string) error {
 	rawCidrs, err := json.Marshal(cidrs)
 	if err != nil {
@@ -189,7 +189,7 @@ func PatchNodeCIDRs(c clientset.Interface, node types.NodeName, cidrs []string)
 
 	// set the pod cidrs list and set the old pod cidr field
 	patchBytes := []byte(fmt.Sprintf(`{"spec":{"podCIDR":%s , "podCIDRs":%s}}`, rawCidr, rawCidrs))
-
+	klog.V(4).Infof("cidrs patch bytes are:%s", string(patchBytes))
 	if _, err := c.CoreV1().Nodes().Patch(string(node), types.StrategicMergePatchType, patchBytes); err != nil {
 		return fmt.Errorf("failed to patch node CIDR: %v", err)
 	}

staging/src/k8s.io/cri-api/pkg/apis/testing/fake_runtime_service.go

@@ -28,8 +28,8 @@ import (
 var (
 	FakeVersion = "0.1.0"
 
-	FakeRuntimeName  = "fakeRuntime"
-	FakePodSandboxIP = "192.168.192.168"
+	FakeRuntimeName   = "fakeRuntime"
+	FakePodSandboxIPs = []string{"192.168.192.168"}
 )
 
 type FakePodSandbox struct {
@@ -192,7 +192,7 @@ func (r *FakeRuntimeService) RunPodSandbox(config *runtimeapi.PodSandboxConfig,
 			State:     runtimeapi.PodSandboxState_SANDBOX_READY,
 			CreatedAt: createdAt,
 			Network: &runtimeapi.PodSandboxNetworkStatus{
-				Ip: FakePodSandboxIP,
+				Ip: FakePodSandboxIPs[0],
 			},
 			Labels:         config.Labels,
 			Annotations:    config.Annotations,
@@ -200,7 +200,15 @@ func (r *FakeRuntimeService) RunPodSandbox(config *runtimeapi.PodSandboxConfig,
 		},
 		RuntimeHandler: runtimeHandler,
 	}
-
+	// assign additional IPs
+	additionalIPs := FakePodSandboxIPs[1:]
+	additionalPodIPs := make([]*runtimeapi.PodIP, 0, len(additionalIPs))
+	for _, ip := range additionalIPs {
+		additionalPodIPs = append(additionalPodIPs, &runtimeapi.PodIP{
+			Ip: ip,
+		})
+	}
+	r.Sandboxes[podSandboxID].PodSandboxStatus.Network.AdditionalIps = additionalPodIPs
 	return podSandboxID, nil
 }