Skip inspecting pod network if unknown namespace

pkg/kubelet/network/cni/cni.go

@@ -266,6 +266,9 @@ func (plugin *cniNetworkPlugin) GetPodNetworkStatus(namespace string, name strin
 	if err != nil {
 		return nil, fmt.Errorf("CNI failed to retrieve network namespace path: %v", err)
 	}
+	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)
 	if err != nil {

pkg/kubelet/network/kubenet/kubenet_linux.go

@@ -558,6 +558,9 @@ func (plugin *kubenetNetworkPlugin) GetPodNetworkStatus(namespace string, name s
 	if err != nil {
 		return nil, fmt.Errorf("Kubenet failed to retrieve network namespace path: %v", err)
 	}
+	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)
 	if err != nil {
 		return nil, err