Support pods with containers using host ipc

Add a HostIPC field to the Pod Spec to create containers sharing
the same ipc of the host.

This feature must be explicitly enabled in apiserver using the
option host-ipc-sources.

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>

api/swagger-spec/v1.json

@@ -12531,6 +12531,10 @@
       "type": "boolean",
       "description": "Use the host's pid namespace. Optional: Default to false."
      },
+     "hostIPC": {
+      "type": "boolean",
+      "description": "Use the host's ipc namespace. Optional: Default to false."
+     },
      "imagePullSecrets": {
       "type": "array",
       "items": {

cmd/kube-apiserver/app/server.go

@@ -293,6 +293,7 @@ func (s *APIServer) Run(_ []string) error {
 		PrivilegedSources: capabilities.PrivilegedSources{
 			HostNetworkSources: []string{},
 			HostPIDSources:     []string{},
+			HostIPCSources:     []string{},
 		},
 		PerConnectionBandwidthLimitBytesPerSec: s.MaxConnectionBytesPerSec,
 	})

cmd/kubelet/app/server.go

@@ -95,6 +95,7 @@ type KubeletServer struct {
 	HostnameOverride               string
 	HostNetworkSources             string
 	HostPIDSources                 string
+	HostIPCSources                 string
 	HTTPCheckFrequency             time.Duration
 	ImageGCHighThresholdPercent    int
 	ImageGCLowThresholdPercent     int
@@ -173,6 +174,7 @@ func NewKubeletServer() *KubeletServer {
 		HealthzPort:                 10248,
 		HostNetworkSources:          kubelet.FileSource,
 		HostPIDSources:              kubelet.FileSource,
+		HostIPCSources:              kubelet.FileSource,
 		HTTPCheckFrequency:          20 * time.Second,
 		ImageGCHighThresholdPercent: 90,
 		ImageGCLowThresholdPercent:  80,
@@ -226,6 +228,7 @@ func (s *KubeletServer) AddFlags(fs *pflag.FlagSet) {
 	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.StringVar(&s.HostPIDSources, "host-pid-sources", s.HostPIDSources, "Comma-separated list of sources from which the Kubelet allows pods to use the host pid namespace. For all sources use \"*\" [default=\"file\"]")
+	fs.StringVar(&s.HostIPCSources, "host-ipc-sources", s.HostIPCSources, "Comma-separated list of sources from which the Kubelet allows pods to use the host ipc namespace. 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.Float32Var(&s.EventRecordQPS, "event-qps", s.EventRecordQPS, "If > 0, limit event creations per second to this value. If 0, unlimited. [default=0.0]")
@@ -287,6 +290,11 @@ func (s *KubeletServer) KubeletConfig() (*KubeletConfig, error) {
 		return nil, err
 	}
 
+	hostIPCSources, err := kubelet.GetValidatedSources(strings.Split(s.HostIPCSources, ","))
+	if err != nil {
+		return nil, err
+	}
+
 	mounter := mount.New()
 	var writer io.Writer = &io.StdWriter{}
 	if s.Containerized {
@@ -354,6 +362,7 @@ func (s *KubeletServer) KubeletConfig() (*KubeletConfig, error) {
 		HostnameOverride:          s.HostnameOverride,
 		HostNetworkSources:        hostNetworkSources,
 		HostPIDSources:            hostPIDSources,
+		HostIPCSources:            hostIPCSources,
 		HTTPCheckFrequency:        s.HTTPCheckFrequency,
 		ImageGCPolicy:             imageGCPolicy,
 		KubeClient:                nil,
@@ -689,6 +698,7 @@ func RunKubelet(kcfg *KubeletConfig, builder KubeletBuilder) error {
 	privilegedSources := capabilities.PrivilegedSources{
 		HostNetworkSources: kcfg.HostNetworkSources,
 		HostPIDSources:     kcfg.HostPIDSources,
+		HostIPCSources:     kcfg.HostIPCSources,
 	}
 	capabilities.Setup(kcfg.AllowPrivileged, privilegedSources, 0)
 
@@ -783,6 +793,7 @@ type KubeletConfig struct {
 	HostnameOverride               string
 	HostNetworkSources             []string
 	HostPIDSources                 []string
+	HostIPCSources                 []string
 	HTTPCheckFrequency             time.Duration
 	ImageGCPolicy                  kubelet.ImageGCPolicy
 	KubeClient                     *client.Client

docs/admin/kubelet.md

@@ -85,6 +85,7 @@ HTTP server: The kubelet can also listen for HTTP and respond to a simple API
   -h, --help=false: help for kubelet
       --host-network-sources="": Comma-separated list of sources from which the Kubelet allows pods to use of host network. For all sources use "*" [default="file"]
       --host-pid-sources="": Comma-separated list of sources from which the Kubelet allows pods to use the host pid namespace. For all sources use "*" [default="file"]
+      --host-ipc-sources="": Comma-separated list of sources from which the Kubelet allows pods to use the host ipc namespace. For all sources use "*" [default="file"]
       --hostname-override="": If non-empty, will use this string as identification instead of the actual hostname.
       --http-check-frequency=0: Duration between checking http for new data
       --image-gc-high-threshold=0: The percent of disk usage after which image garbage collection is always run. Default: 90%%

hack/verify-flags/known-flags.txt

@@ -107,6 +107,7 @@ deployment-controller-sync-period
 hostname-override
 host-network-sources
 host-pid-sources
+host-ipc-sources
 http-check-frequency
 http-port
 ignore-not-found

pkg/api/deep_copy_generated.go

@@ -1452,6 +1452,7 @@ func deepCopy_api_PodSpec(in PodSpec, out *PodSpec, c *conversion.Cloner) error
 	out.NodeName = in.NodeName
 	out.HostNetwork = in.HostNetwork
 	out.HostPID = in.HostPID
+	out.HostIPC = in.HostIPC
 	if in.ImagePullSecrets != nil {
 		out.ImagePullSecrets = make([]LocalObjectReference, len(in.ImagePullSecrets))
 		for i := range in.ImagePullSecrets {

pkg/api/types.go

@@ -959,6 +959,9 @@ type PodSpec struct {
 	// Use the host's pid namespace.
 	// Optional: Default to false.
 	HostPID bool `json:"hostPID,omitempty"`
+	// Use the host's ipc namespace.
+	// Optional: Default to false.
+	HostIPC bool `json:"hostIPC,omitempty"`
 	// ImagePullSecrets is an optional list of references to secrets in the same namespace to use for pulling any of the images used by this PodSpec.
 	// If specified, these secrets will be passed to individual puller implementations for them to use.  For example,
 	// in the case of docker, only DockerConfig type secrets are honored.

pkg/api/v1/conversion.go

@@ -283,6 +283,7 @@ func convert_api_PodSpec_To_v1_PodSpec(in *api.PodSpec, out *PodSpec, s conversi
 	out.NodeName = in.NodeName
 	out.HostNetwork = in.HostNetwork
 	out.HostPID = in.HostPID
+	out.HostIPC = in.HostIPC
 	if in.ImagePullSecrets != nil {
 		out.ImagePullSecrets = make([]LocalObjectReference, len(in.ImagePullSecrets))
 		for i := range in.ImagePullSecrets {
@@ -351,6 +352,7 @@ func convert_v1_PodSpec_To_api_PodSpec(in *PodSpec, out *api.PodSpec, s conversi
 	out.NodeName = in.NodeName
 	out.HostNetwork = in.HostNetwork
 	out.HostPID = in.HostPID
+	out.HostIPC = in.HostIPC
 	if in.ImagePullSecrets != nil {
 		out.ImagePullSecrets = make([]api.LocalObjectReference, len(in.ImagePullSecrets))
 		for i := range in.ImagePullSecrets {

pkg/api/v1/deep_copy_generated.go

@@ -1473,6 +1473,7 @@ func deepCopy_v1_PodSpec(in PodSpec, out *PodSpec, c *conversion.Cloner) error {
 	out.NodeName = in.NodeName
 	out.HostNetwork = in.HostNetwork
 	out.HostPID = in.HostPID
+	out.HostIPC = in.HostIPC
 	if in.ImagePullSecrets != nil {
 		out.ImagePullSecrets = make([]LocalObjectReference, len(in.ImagePullSecrets))
 		for i := range in.ImagePullSecrets {

pkg/api/v1/types.go

@@ -1197,6 +1197,9 @@ type PodSpec struct {
 	// Use the host's pid namespace.
 	// Optional: Default to false.
 	HostPID bool `json:"hostPID,omitempty"`
+	// Use the host's ipc namespace.
+	// Optional: Default to false.
+	HostIPC bool `json:"hostIPC,omitempty"`
 	// ImagePullSecrets is an optional list of references to secrets in the same namespace to use for pulling any of the images used by this PodSpec.
 	// If specified, these secrets will be passed to individual puller implementations for them to use. For example,
 	// in the case of docker, only DockerConfig type secrets are honored.

pkg/api/v1/types_swagger_doc_generated.go

@@ -965,6 +965,7 @@ var map_PodSpec = map[string]string{
 	"nodeName":                      "NodeName is a request to schedule this pod onto a specific node. If it is non-empty, the scheduler simply schedules this pod onto that node, assuming that it fits resource requirements.",
 	"hostNetwork":                   "Host networking requested for this pod. Use the host's network namespace. If this option is set, the ports that will be used must be specified. Default to false.",
 	"hostPID":                       "Use the host's pid namespace. Optional: Default to false.",
+	"hostIPC":                       "Use the host's ipc namespace. Optional: Default to false.",
 	"imagePullSecrets":              "ImagePullSecrets is an optional list of references to secrets in the same namespace to use for pulling any of the images used by this PodSpec. If specified, these secrets will be passed to individual puller implementations for them to use. For example, in the case of docker, only DockerConfig type secrets are honored. More info: http://releases.k8s.io/HEAD/docs/user-guide/images.md#specifying-imagepullsecrets-on-a-pod",
 }
 

pkg/api/validation/validation_test.go

@@ -1249,6 +1249,7 @@ func TestValidatePodSpec(t *testing.T) {
 				},
 			},
 			HostNetwork:   true,
+			HostIPC:       true,
 			RestartPolicy: api.RestartPolicyAlways,
 			DNSPolicy:     api.DNSClusterFirst,
 		},
@@ -1299,6 +1300,7 @@ func TestValidatePodSpec(t *testing.T) {
 				},
 			},
 			HostNetwork:   true,
+			HostIPC:       true,
 			RestartPolicy: api.RestartPolicyAlways,
 			DNSPolicy:     api.DNSClusterFirst,
 		},

pkg/apis/experimental/deep_copy_generated.go

@@ -461,6 +461,7 @@ func deepCopy_api_PodSpec(in api.PodSpec, out *api.PodSpec, c *conversion.Cloner
 	out.NodeName = in.NodeName
 	out.HostNetwork = in.HostNetwork
 	out.HostPID = in.HostPID
+	out.HostIPC = in.HostIPC
 	if in.ImagePullSecrets != nil {
 		out.ImagePullSecrets = make([]api.LocalObjectReference, len(in.ImagePullSecrets))
 		for i := range in.ImagePullSecrets {

pkg/apis/experimental/v1/conversion.go

@@ -99,6 +99,7 @@ func convert_api_PodSpec_To_v1_PodSpec(in *api.PodSpec, out *v1.PodSpec, s conve
 	out.NodeName = in.NodeName
 	out.HostNetwork = in.HostNetwork
 	out.HostPID = in.HostPID
+	out.HostIPC = in.HostIPC
 	if in.ImagePullSecrets != nil {
 		out.ImagePullSecrets = make([]v1.LocalObjectReference, len(in.ImagePullSecrets))
 		for i := range in.ImagePullSecrets {
@@ -167,6 +168,7 @@ func convert_v1_PodSpec_To_api_PodSpec(in *v1.PodSpec, out *api.PodSpec, s conve
 	out.NodeName = in.NodeName
 	out.HostNetwork = in.HostNetwork
 	out.HostPID = in.HostPID
+	out.HostIPC = in.HostIPC
 	if in.ImagePullSecrets != nil {
 		out.ImagePullSecrets = make([]api.LocalObjectReference, len(in.ImagePullSecrets))
 		for i := range in.ImagePullSecrets {

pkg/apis/experimental/v1/deep_copy_generated.go

@@ -500,6 +500,7 @@ func deepCopy_v1_PodSpec(in v1.PodSpec, out *v1.PodSpec, c *conversion.Cloner) e
 	out.NodeName = in.NodeName
 	out.HostNetwork = in.HostNetwork
 	out.HostPID = in.HostPID
+	out.HostIPC = in.HostIPC
 	if in.ImagePullSecrets != nil {
 		out.ImagePullSecrets = make([]v1.LocalObjectReference, len(in.ImagePullSecrets))
 		for i := range in.ImagePullSecrets {

pkg/capabilities/capabilities.go

@@ -41,6 +41,9 @@ type PrivilegedSources struct {
 
 	// List of pod sources for which using host pid namespace is allowed.
 	HostPIDSources []string
+
+	// List of pod sources for which using host ipc is allowed.
+	HostIPCSources []string
 }
 
 // TODO: Clean these up into a singleton
@@ -83,6 +86,7 @@ func Get() Capabilities {
 			PrivilegedSources: PrivilegedSources{
 				HostNetworkSources: []string{},
 				HostPIDSources:     []string{},
+				HostIPCSources:     []string{},
 			},
 		})
 	}

pkg/kubelet/dockertools/manager.go

@@ -1396,7 +1396,7 @@ func containerAndPodFromLabels(inspect *docker.Container) (pod *api.Pod, contain
 }
 
 // Run a single container from a pod. Returns the docker container ID
-func (dm *DockerManager) runContainerInPod(pod *api.Pod, container *api.Container, netMode, ipcMode string, pidMode string) (kubeletTypes.DockerID, error) {
+func (dm *DockerManager) runContainerInPod(pod *api.Pod, container *api.Container, netMode, ipcMode, pidMode string) (kubeletTypes.DockerID, error) {
 	start := time.Now()
 	defer func() {
 		metrics.ContainerManagerLatency.WithLabelValues("runContainerInPod").Observe(metrics.SinceInMicroseconds(start))
@@ -1548,7 +1548,7 @@ func (dm *DockerManager) createPodInfraContainer(pod *api.Pod) (kubeletTypes.Doc
 		return "", err
 	}
 
-	id, err := dm.runContainerInPod(pod, container, netNamespace, "", getPidMode(pod))
+	id, err := dm.runContainerInPod(pod, container, netNamespace, getIPCMode(pod, ""), getPidMode(pod))
 	if err != nil {
 		return "", err
 	}
@@ -1804,7 +1804,7 @@ func (dm *DockerManager) SyncPod(pod *api.Pod, runningPod kubecontainer.Pod, pod
 
 		// TODO(dawnchen): Check RestartPolicy.DelaySeconds before restart a container
 		namespaceMode := fmt.Sprintf("container:%v", podInfraContainerID)
-		_, err = dm.runContainerInPod(pod, container, namespaceMode, namespaceMode, getPidMode(pod))
+		_, err = dm.runContainerInPod(pod, container, namespaceMode, getIPCMode(pod, namespaceMode), getPidMode(pod))
 		dm.updateReasonCache(pod, container, "RunContainerError", err)
 		if err != nil {
 			// TODO(bburns) : Perhaps blacklist a container after N failures?
@@ -1927,3 +1927,11 @@ func getPidMode(pod *api.Pod) string {
 	}
 	return pidMode
 }
+
+// getIPCMode returns the ipc mode to use on the docker container based on pod.Spec.HostIPC.
+func getIPCMode(pod *api.Pod, ipcMode string) string {
+	if pod.Spec.HostIPC {
+		ipcMode = "host"
+	}
+	return ipcMode
+}

pkg/kubelet/dockertools/manager_test.go

@@ -2067,3 +2067,20 @@ func TestGetPidMode(t *testing.T) {
 		t.Errorf("expected host pid mode for pod but got %v", pidMode)
 	}
 }
+
+func TestGetIPCMode(t *testing.T) {
+	// test false
+	pod := &api.Pod{}
+	ipcMode := getIPCMode(pod, "")
+
+	if ipcMode != "" {
+		t.Errorf("expected empty ipc mode for pod but got %v", ipcMode)
+	}
+
+	// test true
+	pod.Spec.HostIPC = true
+	ipcMode = getIPCMode(pod, "")
+	if ipcMode != "host" {
+		t.Errorf("expected host ipc mode for pod but got %v", ipcMode)
+	}
+}

pkg/kubelet/rkt/rkt.go

@@ -594,6 +594,7 @@ func (r *runtime) preparePod(pod *api.Pod, pullSecrets []api.Secret) (string, *k
 	}
 
 	// TODO handle pod.Spec.HostPID
+	// TODO handle pod.Spec.HostIPC
 
 	units := []*unit.UnitOption{
 		newUnitOption(unitKubernetesSection, unitRktID, uuid),

pkg/kubelet/util.go

@@ -60,6 +60,16 @@ func canRunPod(pod *api.Pod) error {
 		}
 	}
 
+	if pod.Spec.HostIPC {
+		allowed, err := allowHostIPC(pod)
+		if err != nil {
+			return err
+		}
+		if !allowed {
+			return fmt.Errorf("pod with UID %q specified host ipc, but is disallowed", pod.UID)
+		}
+	}
+
 	if !capabilities.Get().AllowPrivileged {
 		for _, container := range pod.Spec.Containers {
 			if securitycontext.HasPrivilegedRequest(&container) {
@@ -97,3 +107,17 @@ func allowHostPID(pod *api.Pod) (bool, error) {
 	}
 	return false, nil
 }
+
+// Determined whether the specified pod is allowed to use host ipc
+func allowHostIPC(pod *api.Pod) (bool, error) {
+	podSource, err := getPodSource(pod)
+	if err != nil {
+		return false, err
+	}
+	for _, source := range capabilities.Get().PrivilegedSources.HostIPCSources {
+		if source == podSource {
+			return true, nil
+		}
+	}
+	return false, nil
+}

plugin/pkg/admission/exec/admission.go

@@ -94,10 +94,9 @@ func (d *denyExec) Admit(a admission.Attributes) (err error) {
 		return admission.NewForbidden(a, fmt.Errorf("Cannot exec into or attach to a container using host pid"))
 	}
 
-	//TODO uncomment when this feature lands https://github.com/kubernetes/kubernetes/pull/12470
-	//	if d.hostIPC && pod.Spec.HostIPC {
-	//		return admission.NewForbidden(a, fmt.Errorf("Cannot exec into or attach to a container using host ipc"))
-	//	}
+	if d.hostIPC && pod.Spec.HostIPC {
+		return admission.NewForbidden(a, fmt.Errorf("Cannot exec into or attach to a container using host ipc"))
+	}
 
 	if d.privileged && isPrivileged(pod) {
 		return admission.NewForbidden(a, fmt.Errorf("Cannot exec into or attach to a privileged container"))

plugin/pkg/admission/exec/admission_test.go

@@ -36,8 +36,8 @@ func TestAdmission(t *testing.T) {
 	hostPIDPod := validPod("hostPID")
 	hostPIDPod.Spec.HostPID = true
 
-	//	hostIPCPod := validPod("hostIPC")
-	//	hostIPCPod.Spec.HostIPC = true
+	hostIPCPod := validPod("hostIPC")
+	hostIPCPod.Spec.HostIPC = true
 
 	testCases := map[string]struct {
 		pod          *api.Pod
@@ -51,10 +51,10 @@ func TestAdmission(t *testing.T) {
 			shouldAccept: false,
 			pod:          hostPIDPod,
 		},
-		//		"hostIPC": {
-		//			shouldAccept: false,
-		//			pod: hostIPCPod,
-		//		},
+		"hostIPC": {
+			shouldAccept: false,
+			pod:          hostIPCPod,
+		},
 		"non privileged": {
 			shouldAccept: true,
 			pod:          validPod("nonPrivileged"),
@@ -132,8 +132,8 @@ func TestDenyExecOnPrivileged(t *testing.T) {
 	hostPIDPod := validPod("hostPID")
 	hostPIDPod.Spec.HostPID = true
 
-	//	hostIPCPod := validPod("hostIPC")
-	//	hostIPCPod.Spec.HostIPC = true
+	hostIPCPod := validPod("hostIPC")
+	hostIPCPod.Spec.HostIPC = true
 
 	testCases := map[string]struct {
 		pod          *api.Pod
@@ -147,10 +147,10 @@ func TestDenyExecOnPrivileged(t *testing.T) {
 			shouldAccept: true,
 			pod:          hostPIDPod,
 		},
-		//		"hostIPC": {
-		//			shouldAccept: true,
-		//			pod: hostIPCPod,
-		//		},
+		"hostIPC": {
+			shouldAccept: true,
+			pod:          hostIPCPod,
+		},
 		"non privileged": {
 			shouldAccept: true,
 			pod:          validPod("nonPrivileged"),