Add HostNetworkSources capability to limit use of HostNetwork.

cmd/kube-apiserver/app/server.go

@@ -184,6 +184,8 @@ func (s *APIServer) Run(_ []string) error {
 
 	capabilities.Initialize(capabilities.Capabilities{
 		AllowPrivileged: s.AllowPrivileged,
+		// TODO(vmarmol): Implement support for HostNetworkSources.
+		HostNetworkSources: []string{},
 	})
 
 	cloud := cloudprovider.InitCloudProvider(s.CloudProvider, s.CloudConfigFile)

cmd/kubelet/app/server.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"math/rand"
 	"net"
+	"strings"
 	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
@@ -61,6 +62,7 @@ type KubeletServer struct {
 	DockerEndpoint                 string
 	RootDirectory                  string
 	AllowPrivileged                bool
+	HostNetworkSources             string
 	RegistryPullQPS                float64
 	RegistryBurst                  int
 	RunOnce                        bool
@@ -106,6 +108,7 @@ func NewKubeletServer() *KubeletServer {
 		ImageGCHighThresholdPercent: 90,
 		ImageGCLowThresholdPercent:  80,
 		NetworkPluginName:           "",
+		HostNetworkSources:          kubelet.FileSource,
 	}
 }
 
@@ -124,6 +127,7 @@ func (s *KubeletServer) AddFlags(fs *pflag.FlagSet) {
 	fs.StringVar(&s.DockerEndpoint, "docker_endpoint", s.DockerEndpoint, "If non-empty, use this for the docker endpoint to communicate with")
 	fs.StringVar(&s.RootDirectory, "root_dir", s.RootDirectory, "Directory path for managing kubelet files (volume mounts,etc).")
 	fs.BoolVar(&s.AllowPrivileged, "allow_privileged", s.AllowPrivileged, "If true, allow containers to request privileged mode. [default=false]")
+	fs.StringVar(&s.HostNetworkSources, "host_network_sources", s.HostNetworkSources, "Comma-separated list of sources from which the Kubelet allows pods to use of host network. For all sources use \"*\" [default=\"file\"]")
 	fs.Float64Var(&s.RegistryPullQPS, "registry_qps", s.RegistryPullQPS, "If > 0, limit registry pull QPS to this value.  If 0, unlimited. [default=0.0]")
 	fs.IntVar(&s.RegistryBurst, "registry_burst", s.RegistryBurst, "Maximum size of a bursty pulls, temporarily allows pulls to burst to this number, while still not exceeding registry_qps.  Only used if --registry_qps > 0")
 	fs.BoolVar(&s.RunOnce, "runonce", s.RunOnce, "If true, exit after spawning pods from local manifests or remote urls. Exclusive with --api_servers, and --enable-server")
@@ -178,9 +182,14 @@ func (s *KubeletServer) Run(_ []string) error {
 	cloud := cloudprovider.InitCloudProvider(s.CloudProvider, s.CloudConfigFile)
 	glog.Infof("Successfully initialized cloud provider: %q from the config file: %q\n", s.CloudProvider, s.CloudConfigFile)
 
+	hostNetworkSources, err := kubelet.GetValidatedSources(strings.Split(s.HostNetworkSources, ","))
+	if err != nil {
+		return err
+	}
 	kcfg := KubeletConfig{
 		Address:                        s.Address,
 		AllowPrivileged:                s.AllowPrivileged,
+		HostNetworkSources:             hostNetworkSources,
 		HostnameOverride:               s.HostnameOverride,
 		RootDirectory:                  s.RootDirectory,
 		ConfigFile:                     s.Config,
@@ -321,7 +330,7 @@ func RunKubelet(kcfg *KubeletConfig) {
 		glog.Infof("No api server defined - no events will be sent.")
 	}
 	kubelet.SetupLogging()
-	kubelet.SetupCapabilities(kcfg.AllowPrivileged)
+	kubelet.SetupCapabilities(kcfg.AllowPrivileged, kcfg.HostNetworkSources)
 
 	credentialprovider.SetPreferredDockercfgPath(kcfg.RootDirectory)
 
@@ -383,6 +392,7 @@ type KubeletConfig struct {
 	CadvisorInterface              cadvisor.Interface
 	Address                        util.IP
 	AllowPrivileged                bool
+	HostNetworkSources             []string
 	HostnameOverride               string
 	RootDirectory                  string
 	ConfigFile                     string

pkg/capabilities/capabilities.go

@@ -24,6 +24,9 @@ import (
 // For now these are global.  Eventually they may be per-user
 type Capabilities struct {
 	AllowPrivileged bool
+
+	// List of pod sources for which using host network is allowed.
+	HostNetworkSources []string
 }
 
 var once sync.Once
@@ -46,7 +49,8 @@ func SetForTests(c Capabilities) {
 func Get() Capabilities {
 	if capabilities == nil {
 		Initialize(Capabilities{
-			AllowPrivileged: false,
+			AllowPrivileged:    false,
+			HostNetworkSources: []string{},
 		})
 	}
 	return *capabilities

pkg/kubelet/kubelet.go

@@ -1007,6 +1007,20 @@ const (
 	PodInfraContainerImage = "kubernetes/pause:latest"
 )
 
+// Determined whether the specified pod is allowed to use host networking
+func allowHostNetwork(pod *api.Pod) (bool, error) {
+	podSource, err := getPodSource(pod)
+	if err != nil {
+		return false, err
+	}
+	for _, source := range capabilities.Get().HostNetworkSources {
+		if source == podSource {
+			return true, nil
+		}
+	}
+	return false, nil
+}
+
 // createPodInfraContainer starts the pod infra container for a pod. Returns the docker container ID of the newly created container.
 func (kl *Kubelet) createPodInfraContainer(pod *api.Pod) (dockertools.DockerID, error) {
 	var ports []api.ContainerPort
@@ -1040,11 +1054,21 @@ func (kl *Kubelet) createPodInfraContainer(pod *api.Pod) (dockertools.DockerID,
 	if ref != nil {
 		kl.recorder.Eventf(ref, "pulled", "Successfully pulled image %q", container.Image)
 	}
-	// TODO(vmarmol): Auth.
+
+	// Use host networking if specified and allowed.
 	netNamespace := ""
 	if pod.Spec.HostNetwork {
+		allowed, err := allowHostNetwork(pod)
+		if err != nil {
+			return "", err
+		}
+		if !allowed {
+			return "", fmt.Errorf("pod with UID %q specified host networking, but is disallowed", pod.UID)
+		}
+
 		netNamespace = "host"
 	}
+
 	id, err := kl.runContainer(pod, container, nil, netNamespace, "")
 	if err != nil {
 		return "", err

pkg/kubelet/kubelet_test.go

@@ -35,6 +35,7 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/resource"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client/record"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/cadvisor"
@@ -3456,3 +3457,61 @@ func TestDoNotCacheStatusForStaticPods(t *testing.T) {
 		t.Errorf("unexpected status %#v found for static pod %q", status, podFullName)
 	}
 }
+
+func TestHostNetworkAllowed(t *testing.T) {
+	testKubelet := newTestKubelet(t)
+	kubelet := testKubelet.kubelet
+
+	capabilities.SetForTests(capabilities.Capabilities{
+		HostNetworkSources: []string{ApiserverSource, FileSource},
+	})
+	pod := &api.Pod{
+		ObjectMeta: api.ObjectMeta{
+			UID:       "12345678",
+			Name:      "foo",
+			Namespace: "new",
+			Annotations: map[string]string{
+				ConfigSourceAnnotationKey: FileSource,
+			},
+		},
+		Spec: api.PodSpec{
+			Containers: []api.Container{
+				{Name: "foo"},
+			},
+			HostNetwork: true,
+		},
+	}
+	_, err := kubelet.createPodInfraContainer(pod)
+	if err != nil {
+		t.Errorf("expected pod infra creation to succeed: %v", err)
+	}
+}
+
+func TestHostNetworkDisallowed(t *testing.T) {
+	testKubelet := newTestKubelet(t)
+	kubelet := testKubelet.kubelet
+
+	capabilities.SetForTests(capabilities.Capabilities{
+		HostNetworkSources: []string{},
+	})
+	pod := &api.Pod{
+		ObjectMeta: api.ObjectMeta{
+			UID:       "12345678",
+			Name:      "foo",
+			Namespace: "new",
+			Annotations: map[string]string{
+				ConfigSourceAnnotationKey: FileSource,
+			},
+		},
+		Spec: api.PodSpec{
+			Containers: []api.Container{
+				{Name: "foo"},
+			},
+			HostNetwork: true,
+		},
+	}
+	_, err := kubelet.createPodInfraContainer(pod)
+	if err == nil {
+		t.Errorf("expected pod infra creation to fail")
+	}
+}

pkg/kubelet/types.go

@@ -16,7 +16,11 @@ limitations under the License.
 
 package kubelet
 
-import "github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+import (
+	"fmt"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+)
 
 const ConfigSourceAnnotationKey = "kubernetes.io/config.source"
 const ConfigMirrorAnnotationKey = "kubernetes.io/config.mirror"
@@ -64,3 +68,22 @@ type PodUpdate struct {
 	Op     PodOperation
 	Source string
 }
+
+// Gets all validated sources from the specified sources.
+func GetValidatedSources(sources []string) ([]string, error) {
+	validated := make([]string, 0, len(sources))
+	for _, source := range sources {
+		switch source {
+		case AllSource:
+			return []string{FileSource, HTTPSource, ApiserverSource}, nil
+		case FileSource, HTTPSource, ApiserverSource:
+			validated = append(validated, source)
+			break
+		case "":
+			break
+		default:
+			return []string{}, fmt.Errorf("unknown pod source %q", source)
+		}
+	}
+	return validated, nil
+}

pkg/kubelet/types_test.go

@@ -0,0 +1,44 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kubelet
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetValidatedSources(t *testing.T) {
+	// Empty.
+	sources, err := GetValidatedSources([]string{""})
+	require.NoError(t, err)
+	require.Len(t, sources, 0)
+
+	// Success.
+	sources, err = GetValidatedSources([]string{FileSource, ApiserverSource})
+	require.NoError(t, err)
+	require.Len(t, sources, 2)
+
+	// All.
+	sources, err = GetValidatedSources([]string{AllSource})
+	require.NoError(t, err)
+	require.Len(t, sources, 3)
+
+	// Unknown source.
+	sources, err = GetValidatedSources([]string{"taco"})
+	require.Error(t, err)
+}

pkg/kubelet/util.go

@@ -27,9 +27,10 @@ import (
 )
 
 // TODO: move this into pkg/capabilities
-func SetupCapabilities(allowPrivileged bool) {
+func SetupCapabilities(allowPrivileged bool, hostNetworkSources []string) {
 	capabilities.Initialize(capabilities.Capabilities{
-		AllowPrivileged: allowPrivileged,
+		AllowPrivileged:    allowPrivileged,
+		HostNetworkSources: hostNetworkSources,
 	})
 }