dockershim: move docker to the given cgruop

This change add a container manager inside the dockershim to move docker daemon
and associated processes to a specified cgroup. The original kubelet container
manager will continue checking the name of the cgroup, so that kubelet know how
to report runtime stats.

cmd/kubelet/app/server.go

@@ -431,6 +431,7 @@ func run(s *options.KubeletServer, kubeDeps *kubelet.KubeletDeps) (err error) {
 			CgroupsPerQOS:          s.CgroupsPerQOS,
 			CgroupRoot:             s.CgroupRoot,
 			ProtectKernelDefaults:  s.ProtectKernelDefaults,
+			RuntimeIntegrationType: s.ExperimentalRuntimeIntegrationType,
 		})
 		if err != nil {
 			return err

pkg/kubelet/cm/container_manager.go

@@ -56,6 +56,7 @@ type NodeConfig struct {
 	CgroupsPerQOS          bool
 	CgroupRoot             string
 	ProtectKernelDefaults  bool
+	RuntimeIntegrationType string
 }
 
 type Status struct {

pkg/kubelet/cm/container_manager_linux.go

@@ -327,7 +327,27 @@ func (cm *containerManagerImpl) setupNode() error {
 	systemContainers := []*systemContainer{}
 	if cm.ContainerRuntime == "docker" {
 		dockerVersion := getDockerVersion(cm.cadvisorInterface)
-		if cm.RuntimeCgroupsName != "" {
+		if cm.RuntimeIntegrationType == "cri" {
+			// If kubelet uses CRI, dockershim will manage the cgroups and oom
+			// score for the docker processes.
+			// In the future, NodeSpec should mandate the cgroup that the
+			// runtime processes need to be in. For now, we still check the
+			// cgroup for docker periodically, so that kubelet can recognize
+			// the cgroup for docker and serve stats for the runtime.
+			// TODO(#27097): Fix this after NodeSpec is clearly defined.
+			cm.periodicTasks = append(cm.periodicTasks, func() {
+				glog.V(4).Infof("[ContainerManager]: Adding periodic tasks for docker CRI integration")
+				cont, err := getContainerNameForProcess(dockerProcessName, dockerPidFile)
+				if err != nil {
+					glog.Error(err)
+					return
+				}
+				glog.V(2).Infof("[ContainerManager]: Discovered runtime cgroups name: %s", cont)
+				cm.Lock()
+				defer cm.Unlock()
+				cm.RuntimeCgroupsName = cont
+			})
+		} else if cm.RuntimeCgroupsName != "" {
 			cont := newSystemCgroups(cm.RuntimeCgroupsName)
 			var capacity = api.ResourceList{}
 			if info, err := cm.cadvisorInterface.MachineInfo(); err == nil {
@@ -353,13 +373,13 @@ func (cm *containerManagerImpl) setupNode() error {
 				},
 			}
 			cont.ensureStateFunc = func(manager *fs.Manager) error {
-				return ensureDockerInContainer(dockerVersion, qos.DockerOOMScoreAdj, dockerContainer)
+				return EnsureDockerInContainer(dockerVersion, qos.DockerOOMScoreAdj, dockerContainer)
 			}
 			systemContainers = append(systemContainers, cont)
 		} else {
 			cm.periodicTasks = append(cm.periodicTasks, func() {
 				glog.V(10).Infof("Adding docker daemon periodic tasks")
-				if err := ensureDockerInContainer(dockerVersion, qos.DockerOOMScoreAdj, nil); err != nil {
+				if err := EnsureDockerInContainer(dockerVersion, qos.DockerOOMScoreAdj, nil); err != nil {
 					glog.Error(err)
 					return
 				}
@@ -572,7 +592,10 @@ func getPidsForProcess(name, pidFile string) ([]int, error) {
 }
 
 // Ensures that the Docker daemon is in the desired container.
-func ensureDockerInContainer(dockerVersion semver.Version, oomScoreAdj int, manager *fs.Manager) error {
+// Temporarily export the function to be used by dockershim.
+// TODO(yujuhong): Move this function to dockershim once kubelet migrates to
+// dockershim as the default.
+func EnsureDockerInContainer(dockerVersion semver.Version, oomScoreAdj int, manager *fs.Manager) error {
 	type process struct{ name, file string }
 	dockerProcs := []process{{dockerProcessName, dockerPidFile}}
 	if dockerVersion.GTE(containerdVersion) {

pkg/kubelet/dockershim/BUILD

@@ -31,6 +31,7 @@ go_library(
         "//pkg/kubelet/api:go_default_library",
         "//pkg/kubelet/api/v1alpha1/runtime:go_default_library",
         "//pkg/kubelet/container:go_default_library",
+        "//pkg/kubelet/dockershim/cm:go_default_library",
         "//pkg/kubelet/dockertools:go_default_library",
         "//pkg/kubelet/leaky:go_default_library",
         "//pkg/kubelet/network:go_default_library",

pkg/kubelet/dockershim/cm/BUILD

@@ -0,0 +1,30 @@
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_binary",
+    "go_library",
+    "go_test",
+    "cgo_library",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "container_manager.go",
+        "container_manager_linux.go",
+    ],
+    tags = ["automanaged"],
+    deps = [
+        "//pkg/kubelet/cm:go_default_library",
+        "//pkg/kubelet/dockertools:go_default_library",
+        "//pkg/kubelet/qos:go_default_library",
+        "//pkg/util/wait:go_default_library",
+        "//vendor:github.com/blang/semver",
+        "//vendor:github.com/golang/glog",
+        "//vendor:github.com/opencontainers/runc/libcontainer/cgroups/fs",
+        "//vendor:github.com/opencontainers/runc/libcontainer/configs",
+    ],
+)

pkg/kubelet/dockershim/cm/container_manager.go

@@ -0,0 +1,21 @@
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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 cm
+
+type ContainerManager interface {
+	Start() error
+}

pkg/kubelet/dockershim/cm/container_manager_linux.go

@@ -0,0 +1,147 @@
+// +build linux
+
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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 cm
+
+import (
+	"fmt"
+	"io/ioutil"
+	"regexp"
+	"strconv"
+	"time"
+
+	"github.com/blang/semver"
+	"github.com/golang/glog"
+	"github.com/opencontainers/runc/libcontainer/cgroups/fs"
+	"github.com/opencontainers/runc/libcontainer/configs"
+	kubecm "k8s.io/kubernetes/pkg/kubelet/cm"
+	"k8s.io/kubernetes/pkg/kubelet/dockertools"
+	"k8s.io/kubernetes/pkg/kubelet/qos"
+	"k8s.io/kubernetes/pkg/util/wait"
+)
+
+const (
+	// The percent of the machine memory capacity.
+	dockerMemoryLimitThresholdPercent = kubecm.DockerMemoryLimitThresholdPercent
+
+	// The minimum memory limit allocated to docker container.
+	minDockerMemoryLimit = kubecm.MinDockerMemoryLimit
+
+	// The Docker OOM score adjustment.
+	dockerOOMScoreAdj = qos.DockerOOMScoreAdj
+)
+
+var (
+	memoryCapacityRegexp = regexp.MustCompile(`MemTotal:\s*([0-9]+) kB`)
+)
+
+func NewContainerManager(cgroupsName string, client dockertools.DockerInterface) ContainerManager {
+	return &containerManager{
+		cgroupsName: cgroupsName,
+		client:      client,
+	}
+}
+
+type containerManager struct {
+	// Docker client.
+	client dockertools.DockerInterface
+	// Name of the cgroups.
+	cgroupsName string
+	// Manager for the cgroups.
+	cgroupsManager *fs.Manager
+}
+
+func (m *containerManager) Start() error {
+	// TODO: check if the required cgroups are mounted.
+	if len(m.cgroupsName) != 0 {
+		manager, err := createCgroupManager(m.cgroupsName)
+		if err != nil {
+			return err
+		}
+		m.cgroupsManager = manager
+	}
+	go wait.Until(m.doWork, 5*time.Minute, wait.NeverStop)
+	return nil
+}
+
+func (m *containerManager) doWork() {
+	v, err := m.client.Version()
+	if err != nil {
+		glog.Errorf("Unable to get docker version: %v", err)
+		return
+	}
+	version, err := semver.Parse(v.Version)
+	if err != nil {
+		glog.Errorf("Unable to parse docker version %q: %v", v.Version, err)
+		return
+	}
+	// EnsureDockerInConatiner does two things.
+	//   1. Ensure processes run in the cgroups if m.cgroupsManager is not nil.
+	//   2. Ensure processes have the OOM score applied.
+	if err := kubecm.EnsureDockerInContainer(version, dockerOOMScoreAdj, m.cgroupsManager); err != nil {
+		glog.Errorf("Unable to ensure the docker processes run in the desired containers")
+	}
+}
+
+func createCgroupManager(name string) (*fs.Manager, error) {
+	var memoryLimit uint64
+	memoryCapacity, err := getMemoryCapacity()
+	if err != nil || memoryCapacity*dockerMemoryLimitThresholdPercent/100 < minDockerMemoryLimit {
+		memoryLimit = minDockerMemoryLimit
+	}
+	glog.V(2).Infof("Configure resource-only container %q with memory limit: %d", name, memoryLimit)
+
+	allowAllDevices := true
+	cm := &fs.Manager{
+		Cgroups: &configs.Cgroup{
+			Parent: "/",
+			Name:   name,
+			Resources: &configs.Resources{
+				Memory:          int64(memoryLimit),
+				MemorySwap:      -1,
+				AllowAllDevices: &allowAllDevices,
+			},
+		},
+	}
+	return cm, nil
+}
+
+// getMemoryCapacity returns the memory capacity on the machine in bytes.
+func getMemoryCapacity() (uint64, error) {
+	out, err := ioutil.ReadFile("/proc/meminfo")
+	if err != nil {
+		return 0, err
+	}
+	return parseCapacity(out, memoryCapacityRegexp)
+}
+
+// parseCapacity matches a Regexp in a []byte, returning the resulting value in bytes.
+// Assumes that the value matched by the Regexp is in KB.
+func parseCapacity(b []byte, r *regexp.Regexp) (uint64, error) {
+	matches := r.FindSubmatch(b)
+	if len(matches) != 2 {
+		return 0, fmt.Errorf("failed to match regexp in output: %q", string(b))
+	}
+	m, err := strconv.ParseUint(string(matches[1]), 10, 64)
+	if err != nil {
+		return 0, err
+	}
+
+	// Convert to bytes.
+	return m * 1024, err
+}

pkg/kubelet/dockershim/cm/container_manager_unsupported.go

@@ -0,0 +1,34 @@
+// +build !linux
+
+/*
+Copyright 2016 The Kubernetes Authors.
+
+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 cm
+
+import (
+	"k8s.io/kubernetes/pkg/kubelet/dockertools"
+)
+
+type unsupportedContainerManager struct {
+}
+
+func NewContainerManager(_ string, _ dockertools.DockerInterface) ContainerManager {
+	return &unsupportedContainerManager{}
+}
+
+func (m *unsupportedContainerManager) Start() error {
+	return fmt.Errorf("Container Manager is unsupported in this build")
+}

pkg/kubelet/dockershim/docker_service.go

@@ -26,6 +26,7 @@ import (
 	internalApi "k8s.io/kubernetes/pkg/kubelet/api"
 	runtimeApi "k8s.io/kubernetes/pkg/kubelet/api/v1alpha1/runtime"
 	kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
+	"k8s.io/kubernetes/pkg/kubelet/dockershim/cm"
 	"k8s.io/kubernetes/pkg/kubelet/dockertools"
 	"k8s.io/kubernetes/pkg/kubelet/network"
 	"k8s.io/kubernetes/pkg/kubelet/network/cni"
@@ -92,10 +93,11 @@ type NetworkPluginSettings struct {
 var internalLabelKeys []string = []string{containerTypeLabelKey, containerLogPathLabelKey, sandboxIDLabelKey}
 
 // NOTE: Anything passed to DockerService should be eventually handled in another way when we switch to running the shim as a different process.
-func NewDockerService(client dockertools.DockerInterface, seccompProfileRoot string, podSandboxImage string, streamingConfig *streaming.Config, pluginSettings *NetworkPluginSettings) (DockerService, error) {
+func NewDockerService(client dockertools.DockerInterface, seccompProfileRoot string, podSandboxImage string, streamingConfig *streaming.Config, pluginSettings *NetworkPluginSettings, cgroupsName string) (DockerService, error) {
+	c := dockertools.NewInstrumentedDockerInterface(client)
 	ds := &dockerService{
 		seccompProfileRoot: seccompProfileRoot,
-		client:             dockertools.NewInstrumentedDockerInterface(client),
+		client:             c,
 		os:                 kubecontainer.RealOS{},
 		podSandboxImage:    podSandboxImage,
 		streamingRuntime: &streamingRuntime{
@@ -104,6 +106,7 @@ func NewDockerService(client dockertools.DockerInterface, seccompProfileRoot str
 			// TODO(#35747) - Either deprecate nsenter exec handling, or add support for it here.
 			execHandler: &dockertools.NativeExecHandler{},
 		},
+		containerManager: cm.NewContainerManager(cgroupsName, client),
 	}
 	if streamingConfig != nil {
 		var err error
@@ -135,6 +138,7 @@ type DockerService interface {
 	internalApi.RuntimeService
 	internalApi.ImageManagerService
 	DockerLegacyService
+	Start() error
 }
 
 // DockerLegacyService is an interface that embeds all legacy methods for
@@ -142,6 +146,7 @@ type DockerService interface {
 type DockerLegacyService interface {
 	// Supporting legacy methods for docker.
 	GetContainerLogs(pod *api.Pod, containerID kubecontainer.ContainerID, logOptions *api.PodLogOptions, stdout, stderr io.Writer) (err error)
+
 	LegacyExec(containerID kubecontainer.ContainerID, cmd []string, stdin io.Reader, stdout, stderr io.WriteCloser, tty bool, resize <-chan term.Size) error
 	LegacyAttach(id kubecontainer.ContainerID, stdin io.Reader, stdout, stderr io.WriteCloser, tty bool, resize <-chan term.Size) error
 	LegacyPortForward(sandboxID string, port uint16, stream io.ReadWriteCloser) error
@@ -155,6 +160,7 @@ type dockerService struct {
 	streamingRuntime   *streamingRuntime
 	streamingServer    streaming.Server
 	networkPlugin      network.NetworkPlugin
+	containerManager   cm.ContainerManager
 }
 
 // Version returns the runtime name, runtime version and runtime API version
@@ -214,3 +220,8 @@ type dockerNetworkHost struct {
 	network.LegacyHost
 	*namespaceGetter
 }
+
+// Start initializes and starts components in dockerService.
+func (ds *dockerService) Start() error {
+	return ds.containerManager.Start()
+}

pkg/kubelet/kubelet.go

@@ -509,7 +509,10 @@ func NewMainKubelet(kubeCfg *componentconfig.KubeletConfiguration, kubeDeps *Kub
 		case "cri":
 			// Use the new CRI shim for docker. This is needed for testing the
 			// docker integration through CRI, and may be removed in the future.
-			dockerService, err := dockershim.NewDockerService(klet.dockerClient, kubeCfg.SeccompProfileRoot, kubeCfg.PodInfraContainerImage, nil, &pluginSettings)
+			dockerService, err := dockershim.NewDockerService(klet.dockerClient, kubeCfg.SeccompProfileRoot, kubeCfg.PodInfraContainerImage, nil, &pluginSettings, kubeCfg.RuntimeCgroups)
+			if err != nil {
+				return nil, err
+			}
 			runtimeService := dockerService.(internalApi.RuntimeService)
 			imageService := dockerService.(internalApi.ImageManagerService)
 
@@ -537,6 +540,10 @@ func NewMainKubelet(kubeCfg *componentconfig.KubeletConfiguration, kubeDeps *Kub
 					return nil, err
 				}
 			}
+			// TODO: Find a better place to start the service.
+			if err := dockerService.Start(); err != nil {
+				return nil, err
+			}
 
 			// kubelet defers to the runtime shim to setup networking. Setting
 			// this to nil will prevent it from trying to invoke the plugin.