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docker_service.go
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docker_service.go
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/*
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 dockershim
import (
"fmt"
"net/http"
"sync"
"time"
"github.com/blang/semver"
dockertypes "github.com/docker/docker/api/types"
"github.com/golang/glog"
"golang.org/x/net/context"
"k8s.io/api/core/v1"
runtimeapi "k8s.io/kubernetes/pkg/kubelet/apis/cri/runtime/v1alpha2"
"k8s.io/kubernetes/pkg/kubelet/apis/kubeletconfig"
kubecm "k8s.io/kubernetes/pkg/kubelet/cm"
kubecontainer "k8s.io/kubernetes/pkg/kubelet/container"
"k8s.io/kubernetes/pkg/kubelet/dockershim/cm"
"k8s.io/kubernetes/pkg/kubelet/network"
"k8s.io/kubernetes/pkg/kubelet/network/cni"
"k8s.io/kubernetes/pkg/kubelet/network/hostport"
"k8s.io/kubernetes/pkg/kubelet/network/kubenet"
"k8s.io/kubernetes/pkg/kubelet/server/streaming"
"k8s.io/kubernetes/pkg/kubelet/util/cache"
utilstore "k8s.io/kubernetes/pkg/kubelet/util/store"
"k8s.io/kubernetes/pkg/kubelet/dockershim/libdocker"
"k8s.io/kubernetes/pkg/kubelet/dockershim/metrics"
)
const (
dockerRuntimeName = "docker"
kubeAPIVersion = "0.1.0"
// String used to detect docker host mode for various namespaces (e.g.
// networking). Must match the value returned by docker inspect -f
// '{{.HostConfig.NetworkMode}}'.
namespaceModeHost = "host"
dockerNetNSFmt = "/proc/%v/ns/net"
// Internal docker labels used to identify whether a container is a sandbox
// or a regular container.
// TODO: This is not backward compatible with older containers. We will
// need to add filtering based on names.
containerTypeLabelKey = "io.kubernetes.docker.type"
containerTypeLabelSandbox = "podsandbox"
containerTypeLabelContainer = "container"
containerLogPathLabelKey = "io.kubernetes.container.logpath"
sandboxIDLabelKey = "io.kubernetes.sandbox.id"
// The expiration time of version cache.
versionCacheTTL = 60 * time.Second
defaultCgroupDriver = "cgroupfs"
// TODO: https://github.com/kubernetes/kubernetes/pull/31169 provides experimental
// defaulting of host user namespace that may be enabled when the docker daemon
// is using remapped UIDs.
// Dockershim should provide detection support for a remapping environment .
// This should be included in the feature proposal. Defaulting may still occur according
// to kubelet behavior and system settings in addition to any API flags that may be introduced.
)
// CRIService includes all methods necessary for a CRI server.
type CRIService interface {
runtimeapi.RuntimeServiceServer
runtimeapi.ImageServiceServer
Start() error
}
// DockerService is an interface that embeds the new RuntimeService and
// ImageService interfaces.
type DockerService interface {
CRIService
// For serving streaming calls.
http.Handler
// For supporting legacy features.
DockerLegacyService
}
// NetworkPluginSettings is the subset of kubelet runtime args we pass
// to the container runtime shim so it can probe for network plugins.
// In the future we will feed these directly to a standalone container
// runtime process.
type NetworkPluginSettings struct {
// HairpinMode is best described by comments surrounding the kubelet arg
HairpinMode kubeletconfig.HairpinMode
// NonMasqueradeCIDR is the range of ips which should *not* be included
// in any MASQUERADE rules applied by the plugin
NonMasqueradeCIDR string
// PluginName is the name of the plugin, runtime shim probes for
PluginName string
// PluginBinDir is the directory in which the binaries for the plugin with
// PluginName is kept. The admin is responsible for provisioning these
// binaries before-hand.
PluginBinDir string
// PluginConfDir is the directory in which the admin places a CNI conf.
// Depending on the plugin, this may be an optional field, eg: kubenet
// generates its own plugin conf.
PluginConfDir string
// MTU is the desired MTU for network devices created by the plugin.
MTU int
// RuntimeHost is an interface that serves as a trap-door from plugin back
// into the kubelet.
// TODO: This shouldn't be required, remove once we move host ports into CNI
// and figure out bandwidth shaping. See corresponding comments above
// network.Host interface.
LegacyRuntimeHost network.LegacyHost
}
// namespaceGetter is a wrapper around the dockerService that implements
// the network.NamespaceGetter interface.
type namespaceGetter struct {
ds *dockerService
}
func (n *namespaceGetter) GetNetNS(containerID string) (string, error) {
return n.ds.GetNetNS(containerID)
}
// portMappingGetter is a wrapper around the dockerService that implements
// the network.PortMappingGetter interface.
type portMappingGetter struct {
ds *dockerService
}
func (p *portMappingGetter) GetPodPortMappings(containerID string) ([]*hostport.PortMapping, error) {
return p.ds.GetPodPortMappings(containerID)
}
// dockerNetworkHost implements network.Host by wrapping the legacy host passed in by the kubelet
// and dockerServices which implements the rest of the network host interfaces.
// The legacy host methods are slated for deletion.
type dockerNetworkHost struct {
network.LegacyHost
*namespaceGetter
*portMappingGetter
}
var internalLabelKeys []string = []string{containerTypeLabelKey, containerLogPathLabelKey, sandboxIDLabelKey}
// ClientConfig is parameters used to initialize docker client
type ClientConfig struct {
DockerEndpoint string
RuntimeRequestTimeout time.Duration
ImagePullProgressDeadline time.Duration
// Configuration for fake docker client
EnableSleep bool
WithTraceDisabled bool
}
// NewDockerClientFromConfig create a docker client from given configure
// return nil if nil configure is given.
func NewDockerClientFromConfig(config *ClientConfig) libdocker.Interface {
if config != nil {
// Create docker client.
client := libdocker.ConnectToDockerOrDie(
config.DockerEndpoint,
config.RuntimeRequestTimeout,
config.ImagePullProgressDeadline,
config.WithTraceDisabled,
config.EnableSleep,
)
return client
}
return nil
}
// 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(config *ClientConfig, podSandboxImage string, streamingConfig *streaming.Config,
pluginSettings *NetworkPluginSettings, cgroupsName string, kubeCgroupDriver string, dockershimRootDir string, disableSharedPID bool) (DockerService, error) {
client := NewDockerClientFromConfig(config)
c := libdocker.NewInstrumentedInterface(client)
checkpointHandler, err := NewPersistentCheckpointHandler(dockershimRootDir)
if err != nil {
return nil, err
}
ds := &dockerService{
client: c,
os: kubecontainer.RealOS{},
podSandboxImage: podSandboxImage,
streamingRuntime: &streamingRuntime{
client: client,
execHandler: &NativeExecHandler{},
},
containerManager: cm.NewContainerManager(cgroupsName, client),
checkpointHandler: checkpointHandler,
disableSharedPID: disableSharedPID,
networkReady: make(map[string]bool),
}
// check docker version compatibility.
if err = ds.checkVersionCompatibility(); err != nil {
return nil, err
}
// create streaming server if configured.
if streamingConfig != nil {
var err error
ds.streamingServer, err = streaming.NewServer(*streamingConfig, ds.streamingRuntime)
if err != nil {
return nil, err
}
}
// dockershim currently only supports CNI plugins.
cniPlugins := cni.ProbeNetworkPlugins(pluginSettings.PluginConfDir, pluginSettings.PluginBinDir)
cniPlugins = append(cniPlugins, kubenet.NewPlugin(pluginSettings.PluginBinDir))
netHost := &dockerNetworkHost{
pluginSettings.LegacyRuntimeHost,
&namespaceGetter{ds},
&portMappingGetter{ds},
}
plug, err := network.InitNetworkPlugin(cniPlugins, pluginSettings.PluginName, netHost, pluginSettings.HairpinMode, pluginSettings.NonMasqueradeCIDR, pluginSettings.MTU)
if err != nil {
return nil, fmt.Errorf("didn't find compatible CNI plugin with given settings %+v: %v", pluginSettings, err)
}
ds.network = network.NewPluginManager(plug)
glog.Infof("Docker cri networking managed by %v", plug.Name())
// NOTE: cgroup driver is only detectable in docker 1.11+
cgroupDriver := defaultCgroupDriver
dockerInfo, err := ds.client.Info()
glog.Infof("Docker Info: %+v", dockerInfo)
if err != nil {
glog.Errorf("Failed to execute Info() call to the Docker client: %v", err)
glog.Warningf("Falling back to use the default driver: %q", cgroupDriver)
} else if len(dockerInfo.CgroupDriver) == 0 {
glog.Warningf("No cgroup driver is set in Docker")
glog.Warningf("Falling back to use the default driver: %q", cgroupDriver)
} else {
cgroupDriver = dockerInfo.CgroupDriver
}
if len(kubeCgroupDriver) != 0 && kubeCgroupDriver != cgroupDriver {
return nil, fmt.Errorf("misconfiguration: kubelet cgroup driver: %q is different from docker cgroup driver: %q", kubeCgroupDriver, cgroupDriver)
}
glog.Infof("Setting cgroupDriver to %s", cgroupDriver)
ds.cgroupDriver = cgroupDriver
ds.versionCache = cache.NewObjectCache(
func() (interface{}, error) {
return ds.getDockerVersion()
},
versionCacheTTL,
)
// Register prometheus metrics.
metrics.Register()
return ds, nil
}
type dockerService struct {
client libdocker.Interface
os kubecontainer.OSInterface
podSandboxImage string
streamingRuntime *streamingRuntime
streamingServer streaming.Server
network *network.PluginManager
// Map of podSandboxID :: network-is-ready
networkReady map[string]bool
networkReadyLock sync.Mutex
containerManager cm.ContainerManager
// cgroup driver used by Docker runtime.
cgroupDriver string
checkpointHandler CheckpointHandler
// caches the version of the runtime.
// To be compatible with multiple docker versions, we need to perform
// version checking for some operations. Use this cache to avoid querying
// the docker daemon every time we need to do such checks.
versionCache *cache.ObjectCache
// This option provides an escape hatch to override the new default behavior for Docker under
// the CRI to use a shared PID namespace for all pods. It is temporary and will be removed.
// See proposals/pod-pid-namespace.md for details.
// TODO: Remove once the escape hatch is no longer used (https://issues.k8s.io/41938)
disableSharedPID bool
}
// TODO: handle context.
// Version returns the runtime name, runtime version and runtime API version
func (ds *dockerService) Version(_ context.Context, r *runtimeapi.VersionRequest) (*runtimeapi.VersionResponse, error) {
v, err := ds.getDockerVersion()
if err != nil {
return nil, err
}
return &runtimeapi.VersionResponse{
Version: kubeAPIVersion,
RuntimeName: dockerRuntimeName,
RuntimeVersion: v.Version,
RuntimeApiVersion: v.APIVersion,
}, nil
}
// dockerVersion gets the version information from docker.
func (ds *dockerService) getDockerVersion() (*dockertypes.Version, error) {
v, err := ds.client.Version()
if err != nil {
return nil, fmt.Errorf("failed to get docker version: %v", err)
}
// Docker API version (e.g., 1.23) is not semver compatible. Add a ".0"
// suffix to remedy this.
v.APIVersion = fmt.Sprintf("%s.0", v.APIVersion)
return v, nil
}
// UpdateRuntimeConfig updates the runtime config. Currently only handles podCIDR updates.
func (ds *dockerService) UpdateRuntimeConfig(_ context.Context, r *runtimeapi.UpdateRuntimeConfigRequest) (*runtimeapi.UpdateRuntimeConfigResponse, error) {
runtimeConfig := r.GetRuntimeConfig()
if runtimeConfig == nil {
return &runtimeapi.UpdateRuntimeConfigResponse{}, nil
}
glog.Infof("docker cri received runtime config %+v", runtimeConfig)
if ds.network != nil && runtimeConfig.NetworkConfig.PodCidr != "" {
event := make(map[string]interface{})
event[network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE_DETAIL_CIDR] = runtimeConfig.NetworkConfig.PodCidr
ds.network.Event(network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE, event)
}
return &runtimeapi.UpdateRuntimeConfigResponse{}, nil
}
// GetNetNS returns the network namespace of the given containerID. The ID
// supplied is typically the ID of a pod sandbox. This getter doesn't try
// to map non-sandbox IDs to their respective sandboxes.
func (ds *dockerService) GetNetNS(podSandboxID string) (string, error) {
r, err := ds.client.InspectContainer(podSandboxID)
if err != nil {
return "", err
}
return getNetworkNamespace(r)
}
// GetPodPortMappings returns the port mappings of the given podSandbox ID.
func (ds *dockerService) GetPodPortMappings(podSandboxID string) ([]*hostport.PortMapping, error) {
// TODO: get portmappings from docker labels for backward compatibility
checkpoint, err := ds.checkpointHandler.GetCheckpoint(podSandboxID)
// Return empty portMappings if checkpoint is not found
if err != nil {
if err == utilstore.ErrKeyNotFound {
return nil, nil
}
return nil, err
}
portMappings := make([]*hostport.PortMapping, 0, len(checkpoint.Data.PortMappings))
for _, pm := range checkpoint.Data.PortMappings {
proto := toAPIProtocol(*pm.Protocol)
portMappings = append(portMappings, &hostport.PortMapping{
HostPort: *pm.HostPort,
ContainerPort: *pm.ContainerPort,
Protocol: proto,
})
}
return portMappings, nil
}
// Start initializes and starts components in dockerService.
func (ds *dockerService) Start() error {
// Initialize the legacy cleanup flag.
return ds.containerManager.Start()
}
// Status returns the status of the runtime.
// TODO(random-liu): Set network condition accordingly here.
func (ds *dockerService) Status(_ context.Context, r *runtimeapi.StatusRequest) (*runtimeapi.StatusResponse, error) {
runtimeReady := &runtimeapi.RuntimeCondition{
Type: runtimeapi.RuntimeReady,
Status: true,
}
networkReady := &runtimeapi.RuntimeCondition{
Type: runtimeapi.NetworkReady,
Status: true,
}
conditions := []*runtimeapi.RuntimeCondition{runtimeReady, networkReady}
if _, err := ds.client.Version(); err != nil {
runtimeReady.Status = false
runtimeReady.Reason = "DockerDaemonNotReady"
runtimeReady.Message = fmt.Sprintf("docker: failed to get docker version: %v", err)
}
if err := ds.network.Status(); err != nil {
networkReady.Status = false
networkReady.Reason = "NetworkPluginNotReady"
networkReady.Message = fmt.Sprintf("docker: network plugin is not ready: %v", err)
}
status := &runtimeapi.RuntimeStatus{Conditions: conditions}
return &runtimeapi.StatusResponse{Status: status}, nil
}
func (ds *dockerService) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if ds.streamingServer != nil {
ds.streamingServer.ServeHTTP(w, r)
} else {
http.NotFound(w, r)
}
}
// GenerateExpectedCgroupParent returns cgroup parent in syntax expected by cgroup driver
func (ds *dockerService) GenerateExpectedCgroupParent(cgroupParent string) (string, error) {
if len(cgroupParent) > 0 {
// if docker uses the systemd cgroup driver, it expects *.slice style names for cgroup parent.
// if we configured kubelet to use --cgroup-driver=cgroupfs, and docker is configured to use systemd driver
// docker will fail to launch the container because the name we provide will not be a valid slice.
// this is a very good thing.
if ds.cgroupDriver == "systemd" {
systemdCgroupParent, err := kubecm.ConvertCgroupFsNameToSystemd(cgroupParent)
if err != nil {
return "", err
}
cgroupParent = systemdCgroupParent
}
}
glog.V(3).Infof("Setting cgroup parent to: %q", cgroupParent)
return cgroupParent, nil
}
// checkVersionCompatibility verifies whether docker is in a compatible version.
func (ds *dockerService) checkVersionCompatibility() error {
apiVersion, err := ds.getDockerAPIVersion()
if err != nil {
return err
}
minAPIVersion, err := semver.Parse(libdocker.MinimumDockerAPIVersion)
if err != nil {
return err
}
// Verify the docker version.
result := apiVersion.Compare(minAPIVersion)
if result < 0 {
return fmt.Errorf("docker API version is older than %s", libdocker.MinimumDockerAPIVersion)
}
return nil
}
// getDockerAPIVersion gets the semver-compatible docker api version.
func (ds *dockerService) getDockerAPIVersion() (*semver.Version, error) {
var dv *dockertypes.Version
var err error
if ds.versionCache != nil {
dv, err = ds.getDockerVersionFromCache()
} else {
dv, err = ds.getDockerVersion()
}
if err != nil {
return nil, err
}
apiVersion, err := semver.Parse(dv.APIVersion)
if err != nil {
return nil, err
}
return &apiVersion, nil
}
func (ds *dockerService) getDockerVersionFromCache() (*dockertypes.Version, error) {
// We only store on key in the cache.
const dummyKey = "version"
value, err := ds.versionCache.Get(dummyKey)
if err != nil {
return nil, err
}
dv, ok := value.(*dockertypes.Version)
if !ok {
return nil, fmt.Errorf("Converted to *dockertype.Version error")
}
return dv, nil
}
func toAPIProtocol(protocol Protocol) v1.Protocol {
switch protocol {
case protocolTCP:
return v1.ProtocolTCP
case protocolUDP:
return v1.ProtocolUDP
}
glog.Warningf("Unknown protocol %q: defaulting to TCP", protocol)
return v1.ProtocolTCP
}