kubelet/dockershim/network: pass ipRange dynamically to the CNI plugin

CNI now supports passing ipRanges dynamically. Pass podCIDR so that
plugins no longer have to look it up.

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

@@ -50,6 +50,7 @@ type cniNetworkPlugin struct {
 	nsenterPath string
 	confDir     string
 	binDirs     []string
+	podCidr     string
 }
 
 type cniNetwork struct {
@@ -83,6 +84,11 @@ type cniBandwidthEntry struct {
 	EgressBurst int `json:"egressBurst,omitempty"`
 }
 
+// cniIpRange maps to the standard CNI ip range Capability
+type cniIpRange struct {
+	Subnet string `json:"subnet"`
+}
+
 func SplitDirs(dirs string) []string {
 	// Use comma rather than colon to work better with Windows too
 	return strings.Split(dirs, ",")
@@ -152,6 +158,8 @@ func getDefaultCNINetwork(confDir string, binDirs []string) (*cniNetwork, error)
 			continue
 		}
 
+		glog.V(4).Infof("Using CNI configuration file %s", confFile)
+
 		network := &cniNetwork{
 			name:          confList.Name,
 			NetworkConfig: confList,
@@ -199,9 +207,43 @@ func (plugin *cniNetworkPlugin) checkInitialized() error {
 	if plugin.getDefaultNetwork() == nil {
 		return errors.New("cni config uninitialized")
 	}
+
+	// If the CNI configuration has the ipRanges capability, we need a PodCIDR assigned
+	for _, p := range plugin.getDefaultNetwork().NetworkConfig.Plugins {
+		if p.Network.Capabilities["ipRanges"] {
+			if plugin.podCidr == "" {
+				return errors.New("no PodCIDR set")
+			}
+			break
+		}
+	}
 	return nil
 }
 
+// Event handles any change events. The only event ever sent is the PodCIDR change.
+// No network plugins support changing an already-set PodCIDR
+func (plugin *cniNetworkPlugin) Event(name string, details map[string]interface{}) {
+	if name != network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE {
+		return
+	}
+
+	plugin.Lock()
+	defer plugin.Unlock()
+
+	podCIDR, ok := details[network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE_DETAIL_CIDR].(string)
+	if !ok {
+		glog.Warningf("%s event didn't contain pod CIDR", network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE)
+		return
+	}
+
+	if plugin.podCidr != "" {
+		glog.Warningf("Ignoring subsequent pod CIDR update to %s", podCIDR)
+		return
+	}
+
+	plugin.podCidr = podCIDR
+}
+
 func (plugin *cniNetworkPlugin) Name() string {
 	return CNIPluginName
 }
@@ -346,5 +388,8 @@ func (plugin *cniNetworkPlugin) buildCNIRuntimeConf(podName string, podNs string
 		rt.CapabilityArgs["bandwidth"] = bandwidthParam
 	}
 
+	// Set the PodCIDR
+	rt.CapabilityArgs["ipRanges"] = [][]cniIpRange{{{Subnet: plugin.podCidr}}}
+
 	return rt, nil
 }

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

@@ -61,7 +61,7 @@ func installPluginUnderTest(t *testing.T, testBinDir, testConfDir, testDataDir,
 	if err != nil {
 		t.Fatalf("Failed to install plugin %s: %v", confFile, err)
 	}
-	networkConfig := fmt.Sprintf(`{ "name": "%s", "type": "%s", "capabilities": {"portMappings": true, "bandwidth": true}  }`, confName, binName)
+	networkConfig := fmt.Sprintf(`{ "name": "%s", "type": "%s", "capabilities": {"portMappings": true, "bandwidth": true, "ipRanges": true}  }`, confName, binName)
 	_, err = f.WriteString(networkConfig)
 	if err != nil {
 		t.Fatalf("Failed to write network config file (%v)", err)
@@ -218,6 +218,19 @@ func TestCNIPlugin(t *testing.T) {
 
 	mockLoCNI.On("AddNetworkList", cniPlugin.loNetwork.NetworkConfig, mock.AnythingOfType("*libcni.RuntimeConf")).Return(&types020.Result{IP4: &types020.IPConfig{IP: net.IPNet{IP: []byte{127, 0, 0, 1}}}}, nil)
 
+	// Check that status returns an error
+	if err := cniPlugin.Status(); err == nil {
+		t.Fatalf("cniPlugin returned non-err with no podCidr")
+	}
+
+	cniPlugin.Event(network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE, map[string]interface{}{
+		network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE_DETAIL_CIDR: "10.0.2.0/24",
+	})
+
+	if err := cniPlugin.Status(); err != nil {
+		t.Fatalf("unexpected status err: %v", err)
+	}
+
 	ports := map[string][]*hostport.PortMapping{
 		containerID.ID: {
 			{
@@ -259,8 +272,9 @@ func TestCNIPlugin(t *testing.T) {
 	// Verify the correct network configuration was passed
 	inputConfig := struct {
 		RuntimeConfig struct {
-			Bandwidth    map[string]interface{}   `json:"bandwidth"`
 			PortMappings []map[string]interface{}   `json:"portMappings"`
+			Bandwidth    map[string]interface{}     `json:"bandwidth"`
+			IpRanges     [][]map[string]interface{} `json:"ipRanges"`
 		} `json:"runtimeConfig"`
 	}{}
 	inputBytes, inerr := ioutil.ReadFile(inputFile)
@@ -282,6 +296,16 @@ func TestCNIPlugin(t *testing.T) {
 		t.Errorf("mismatch in expected bandwidth. expected %v got %v", expectedBandwidth, inputConfig.RuntimeConfig.Bandwidth)
 	}
 
+	expectedIpRange := [][]map[string]interface{}{
+		{
+			{"subnet": "10.0.2.0/24"},
+		},
+	}
+
+	if !reflect.DeepEqual(inputConfig.RuntimeConfig.IpRanges, expectedIpRange) {
+		t.Errorf("mismatch in expected ipRange. expected %v got %v", expectedIpRange, inputConfig.RuntimeConfig.IpRanges)
+	}
+
 	// Get its IP address
 	status, err := plug.GetPodNetworkStatus("podNamespace", "podName", containerID)
 	if err != nil {