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kubelet.go
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kubelet.go
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/*
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 (
"fmt"
"io"
"io/ioutil"
"net"
"net/http"
"os"
"path"
"sort"
"strconv"
"strings"
"sync"
"time"
"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
"github.com/GoogleCloudPlatform/kubernetes/pkg/api/validation"
"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
"github.com/GoogleCloudPlatform/kubernetes/pkg/client/cache"
"github.com/GoogleCloudPlatform/kubernetes/pkg/client/record"
"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/dockertools"
"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/envvars"
"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/metrics"
"github.com/GoogleCloudPlatform/kubernetes/pkg/kubelet/volume"
"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
"github.com/GoogleCloudPlatform/kubernetes/pkg/probe"
"github.com/GoogleCloudPlatform/kubernetes/pkg/tools"
"github.com/GoogleCloudPlatform/kubernetes/pkg/types"
"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
"github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
"github.com/fsouza/go-dockerclient"
"github.com/golang/glog"
)
// taken from lmctfy https://github.com/google/lmctfy/blob/master/lmctfy/controllers/cpu_controller.cc
const minShares = 2
const sharesPerCPU = 1024
const milliCPUToCPU = 1000
// The oom_score_adj of the POD infrastructure container. The default is 0, so
// any value below that makes it *less* likely to get OOM killed.
const podOomScoreAdj = -100
// SyncHandler is an interface implemented by Kubelet, for testability
type SyncHandler interface {
// Syncs current state to match the specified pods. SyncPodType specified what
// type of sync is occuring per pod. StartTime specifies the time at which
// syncing began (for use in monitoring).
SyncPods(pods []api.BoundPod, podSyncTypes map[types.UID]metrics.SyncPodType, startTime time.Time) error
}
type SourceReadyFn func(source string) bool
type volumeMap map[string]volume.Interface
// New creates a new Kubelet for use in main
func NewMainKubelet(
hostname string,
dockerClient dockertools.DockerInterface,
etcdClient tools.EtcdClient,
kubeClient *client.Client,
rootDirectory string,
podInfraContainerImage string,
resyncInterval time.Duration,
pullQPS float32,
pullBurst int,
minimumGCAge time.Duration,
maxContainerCount int,
sourceReady SourceReadyFn,
clusterDomain string,
clusterDNS net.IP,
masterServiceNamespace string,
volumePlugins []volume.Plugin,
streamingConnectionIdleTimeout time.Duration) (*Kubelet, error) {
if rootDirectory == "" {
return nil, fmt.Errorf("invalid root directory %q", rootDirectory)
}
if resyncInterval <= 0 {
return nil, fmt.Errorf("invalid sync frequency %d", resyncInterval)
}
if minimumGCAge <= 0 {
return nil, fmt.Errorf("invalid minimum GC age %d", minimumGCAge)
}
serviceStore := cache.NewStore(cache.MetaNamespaceKeyFunc)
if kubeClient != nil {
cache.NewReflector(cache.NewListWatchFromClient(kubeClient, "services", api.NamespaceAll, labels.Everything()), &api.Service{}, serviceStore).Run()
}
serviceLister := &cache.StoreToServiceLister{serviceStore}
dockerClient = metrics.NewInstrumentedDockerInterface(dockerClient)
klet := &Kubelet{
hostname: hostname,
dockerClient: dockerClient,
etcdClient: etcdClient,
kubeClient: kubeClient,
rootDirectory: rootDirectory,
resyncInterval: resyncInterval,
podInfraContainerImage: podInfraContainerImage,
dockerIDToRef: map[dockertools.DockerID]*api.ObjectReference{},
runner: dockertools.NewDockerContainerCommandRunner(dockerClient),
httpClient: &http.Client{},
pullQPS: pullQPS,
pullBurst: pullBurst,
minimumGCAge: minimumGCAge,
maxContainerCount: maxContainerCount,
sourceReady: sourceReady,
clusterDomain: clusterDomain,
clusterDNS: clusterDNS,
serviceLister: serviceLister,
masterServiceNamespace: masterServiceNamespace,
prober: newProbeHolder(),
readiness: newReadinessStates(),
streamingConnectionIdleTimeout: streamingConnectionIdleTimeout,
}
dockerCache, err := dockertools.NewDockerCache(dockerClient)
if err != nil {
return nil, err
}
klet.dockerCache = dockerCache
klet.podWorkers = newPodWorkers(dockerCache, klet.syncPod)
metrics.Register(dockerCache)
if err = klet.setupDataDirs(); err != nil {
return nil, err
}
if err = klet.volumePluginMgr.InitPlugins(volumePlugins, &volumeHost{klet}); err != nil {
return nil, err
}
return klet, nil
}
type httpGetter interface {
Get(url string) (*http.Response, error)
}
type serviceLister interface {
List() (api.ServiceList, error)
}
// Kubelet is the main kubelet implementation.
type Kubelet struct {
hostname string
dockerClient dockertools.DockerInterface
dockerCache dockertools.DockerCache
kubeClient *client.Client
rootDirectory string
podInfraContainerImage string
podWorkers *podWorkers
resyncInterval time.Duration
sourceReady SourceReadyFn
// Protects the pods array
// We make complete array copies out of this while locked, which is OK because once added to this array,
// pods are immutable
podLock sync.RWMutex
pods []api.BoundPod
// Needed to report events for containers belonging to deleted/modified pods.
// Tracks references for reporting events
dockerIDToRef map[dockertools.DockerID]*api.ObjectReference
refLock sync.RWMutex
// Optional, no events will be sent without it
etcdClient tools.EtcdClient
// Optional, defaults to simple Docker implementation
dockerPuller dockertools.DockerPuller
// Optional, defaults to /logs/ from /var/log
logServer http.Handler
// Optional, defaults to simple Docker implementation
runner dockertools.ContainerCommandRunner
// Optional, client for http requests, defaults to empty client
httpClient httpGetter
// Optional, maximum pull QPS from the docker registry, 0.0 means unlimited.
pullQPS float32
// Optional, maximum burst QPS from the docker registry, must be positive if QPS is > 0.0
pullBurst int
// Optional, no statistics will be available if omitted
cadvisorClient cadvisorInterface
cadvisorLock sync.RWMutex
// Optional, minimum age required for garbage collection. If zero, no limit.
minimumGCAge time.Duration
maxContainerCount int
// If non-empty, use this for container DNS search.
clusterDomain string
// If non-nil, use this for container DNS server.
clusterDNS net.IP
masterServiceNamespace string
serviceLister serviceLister
// Volume plugins.
volumePluginMgr volume.PluginMgr
// probe runner holder
prober probeHolder
// container readiness state holder
readiness *readinessStates
// how long to keep idle streaming command execution/port forwarding
// connections open before terminating them
streamingConnectionIdleTimeout time.Duration
}
// getRootDir returns the full path to the directory under which kubelet can
// store data. These functions are useful to pass interfaces to other modules
// that may need to know where to write data without getting a whole kubelet
// instance.
func (kl *Kubelet) getRootDir() string {
return kl.rootDirectory
}
// getPodsDir returns the full path to the directory under which pod
// directories are created.
func (kl *Kubelet) getPodsDir() string {
return path.Join(kl.getRootDir(), "pods")
}
// getPluginsDir returns the full path to the directory under which plugin
// directories are created. Plugins can use these directories for data that
// they need to persist. Plugins should create subdirectories under this named
// after their own names.
func (kl *Kubelet) getPluginsDir() string {
return path.Join(kl.getRootDir(), "plugins")
}
// getPluginDir returns a data directory name for a given plugin name.
// Plugins can use these directories to store data that they need to persist.
// For per-pod plugin data, see getPodPluginDir.
func (kl *Kubelet) getPluginDir(pluginName string) string {
return path.Join(kl.getPluginsDir(), pluginName)
}
// getPodDir returns the full path to the per-pod data directory for the
// specified pod. This directory may not exist if the pod does not exist.
func (kl *Kubelet) getPodDir(podUID types.UID) string {
// Backwards compat. The "old" stuff should be removed before 1.0
// release. The thinking here is this:
// !old && !new = use new
// !old && new = use new
// old && !new = use old
// old && new = use new (but warn)
oldPath := path.Join(kl.getRootDir(), string(podUID))
oldExists := dirExists(oldPath)
newPath := path.Join(kl.getPodsDir(), string(podUID))
newExists := dirExists(newPath)
if oldExists && !newExists {
return oldPath
}
if oldExists {
glog.Warningf("Data dir for pod %q exists in both old and new form, using new", podUID)
}
return newPath
}
// getPodVolumesDir returns the full path to the per-pod data directory under
// which volumes are created for the specified pod. This directory may not
// exist if the pod does not exist.
func (kl *Kubelet) getPodVolumesDir(podUID types.UID) string {
return path.Join(kl.getPodDir(podUID), "volumes")
}
// getPodVolumeDir returns the full path to the directory which represents the
// named volume under the named plugin for specified pod. This directory may not
// exist if the pod does not exist.
func (kl *Kubelet) getPodVolumeDir(podUID types.UID, pluginName string, volumeName string) string {
return path.Join(kl.getPodVolumesDir(podUID), pluginName, volumeName)
}
// getPodPluginsDir returns the full path to the per-pod data directory under
// which plugins may store data for the specified pod. This directory may not
// exist if the pod does not exist.
func (kl *Kubelet) getPodPluginsDir(podUID types.UID) string {
return path.Join(kl.getPodDir(podUID), "plugins")
}
// getPodPluginDir returns a data directory name for a given plugin name for a
// given pod UID. Plugins can use these directories to store data that they
// need to persist. For non-per-pod plugin data, see getPluginDir.
func (kl *Kubelet) getPodPluginDir(podUID types.UID, pluginName string) string {
return path.Join(kl.getPodPluginsDir(podUID), pluginName)
}
// getPodContainerDir returns the full path to the per-pod data directory under
// which container data is held for the specified pod. This directory may not
// exist if the pod or container does not exist.
func (kl *Kubelet) getPodContainerDir(podUID types.UID, ctrName string) string {
// Backwards compat. The "old" stuff should be removed before 1.0
// release. The thinking here is this:
// !old && !new = use new
// !old && new = use new
// old && !new = use old
// old && new = use new (but warn)
oldPath := path.Join(kl.getPodDir(podUID), ctrName)
oldExists := dirExists(oldPath)
newPath := path.Join(kl.getPodDir(podUID), "containers", ctrName)
newExists := dirExists(newPath)
if oldExists && !newExists {
return oldPath
}
if oldExists {
glog.Warningf("Data dir for pod %q, container %q exists in both old and new form, using new", podUID, ctrName)
}
return newPath
}
func dirExists(path string) bool {
s, err := os.Stat(path)
if err != nil {
return false
}
return s.IsDir()
}
func (kl *Kubelet) setupDataDirs() error {
kl.rootDirectory = path.Clean(kl.rootDirectory)
if err := os.MkdirAll(kl.getRootDir(), 0750); err != nil {
return fmt.Errorf("error creating root directory: %v", err)
}
if err := os.MkdirAll(kl.getPodsDir(), 0750); err != nil {
return fmt.Errorf("error creating pods directory: %v", err)
}
if err := os.MkdirAll(kl.getPluginsDir(), 0750); err != nil {
return fmt.Errorf("error creating plugins directory: %v", err)
}
return nil
}
// Get a list of pods that have data directories.
func (kl *Kubelet) listPodsFromDisk() ([]types.UID, error) {
podInfos, err := ioutil.ReadDir(kl.getPodsDir())
if err != nil {
return nil, err
}
pods := []types.UID{}
for i := range podInfos {
if podInfos[i].IsDir() {
pods = append(pods, types.UID(podInfos[i].Name()))
}
}
return pods, nil
}
type ByCreated []*docker.Container
func (a ByCreated) Len() int { return len(a) }
func (a ByCreated) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a ByCreated) Less(i, j int) bool { return a[i].Created.After(a[j].Created) }
// TODO: these removals are racy, we should make dockerclient threadsafe across List/Inspect transactions.
func (kl *Kubelet) purgeOldest(ids []string) error {
dockerData := []*docker.Container{}
for _, id := range ids {
data, err := kl.dockerClient.InspectContainer(id)
if err != nil {
return err
}
if !data.State.Running && (time.Now().Sub(data.State.FinishedAt) > kl.minimumGCAge) {
dockerData = append(dockerData, data)
}
}
sort.Sort(ByCreated(dockerData))
if len(dockerData) <= kl.maxContainerCount {
return nil
}
dockerData = dockerData[kl.maxContainerCount:]
for _, data := range dockerData {
if err := kl.dockerClient.RemoveContainer(docker.RemoveContainerOptions{ID: data.ID}); err != nil {
return err
}
}
return nil
}
func (kl *Kubelet) GarbageCollectLoop() {
util.Forever(func() {
if err := kl.GarbageCollectContainers(); err != nil {
glog.Errorf("Garbage collect failed: %v", err)
}
}, time.Minute*1)
}
// TODO: Also enforce a maximum total number of containers.
func (kl *Kubelet) GarbageCollectContainers() error {
if kl.maxContainerCount == 0 {
return nil
}
containers, err := dockertools.GetKubeletDockerContainers(kl.dockerClient, true)
if err != nil {
return err
}
uidToIDMap := map[string][]string{}
for _, container := range containers {
_, uid, name, _ := dockertools.ParseDockerName(container.Names[0])
uidName := string(uid) + "." + name
uidToIDMap[uidName] = append(uidToIDMap[uidName], container.ID)
}
for _, list := range uidToIDMap {
if len(list) <= kl.maxContainerCount {
continue
}
if err := kl.purgeOldest(list); err != nil {
return err
}
}
return nil
}
// SetCadvisorClient sets the cadvisor client in a thread-safe way.
func (kl *Kubelet) SetCadvisorClient(c cadvisorInterface) {
kl.cadvisorLock.Lock()
defer kl.cadvisorLock.Unlock()
kl.cadvisorClient = c
}
// GetCadvisorClient gets the cadvisor client.
func (kl *Kubelet) GetCadvisorClient() cadvisorInterface {
kl.cadvisorLock.RLock()
defer kl.cadvisorLock.RUnlock()
return kl.cadvisorClient
}
// Run starts the kubelet reacting to config updates
func (kl *Kubelet) Run(updates <-chan PodUpdate) {
if kl.logServer == nil {
kl.logServer = http.StripPrefix("/logs/", http.FileServer(http.Dir("/var/log/")))
}
if kl.dockerPuller == nil {
kl.dockerPuller = dockertools.NewDockerPuller(kl.dockerClient, kl.pullQPS, kl.pullBurst)
}
kl.syncLoop(updates, kl)
}
func makeBinds(pod *api.BoundPod, container *api.Container, podVolumes volumeMap) []string {
binds := []string{}
for _, mount := range container.VolumeMounts {
vol, ok := podVolumes[mount.Name]
if !ok {
continue
}
b := fmt.Sprintf("%s:%s", vol.GetPath(), mount.MountPath)
if mount.ReadOnly {
b += ":ro"
}
binds = append(binds, b)
}
return binds
}
func makePortsAndBindings(container *api.Container) (map[docker.Port]struct{}, map[docker.Port][]docker.PortBinding) {
exposedPorts := map[docker.Port]struct{}{}
portBindings := map[docker.Port][]docker.PortBinding{}
for _, port := range container.Ports {
exteriorPort := port.HostPort
if exteriorPort == 0 {
// No need to do port binding when HostPort is not specified
continue
}
interiorPort := port.ContainerPort
// Some of this port stuff is under-documented voodoo.
// See http://stackoverflow.com/questions/20428302/binding-a-port-to-a-host-interface-using-the-rest-api
var protocol string
switch strings.ToUpper(string(port.Protocol)) {
case "UDP":
protocol = "/udp"
case "TCP":
protocol = "/tcp"
default:
glog.Warningf("Unknown protocol %q: defaulting to TCP", port.Protocol)
protocol = "/tcp"
}
dockerPort := docker.Port(strconv.Itoa(interiorPort) + protocol)
exposedPorts[dockerPort] = struct{}{}
portBindings[dockerPort] = []docker.PortBinding{
{
HostPort: strconv.Itoa(exteriorPort),
HostIP: port.HostIP,
},
}
}
return exposedPorts, portBindings
}
func milliCPUToShares(milliCPU int64) int64 {
if milliCPU == 0 {
// zero milliCPU means unset. Use kernel default.
return 0
}
// Conceptually (milliCPU / milliCPUToCPU) * sharesPerCPU, but factored to improve rounding.
shares := (milliCPU * sharesPerCPU) / milliCPUToCPU
if shares < minShares {
return minShares
}
return shares
}
func makeCapabilites(capAdd []api.CapabilityType, capDrop []api.CapabilityType) ([]string, []string) {
var (
addCaps []string
dropCaps []string
)
for _, cap := range capAdd {
addCaps = append(addCaps, string(cap))
}
for _, cap := range capDrop {
dropCaps = append(dropCaps, string(cap))
}
return addCaps, dropCaps
}
// A basic interface that knows how to execute handlers
type actionHandler interface {
Run(podFullName string, uid types.UID, container *api.Container, handler *api.Handler) error
}
func (kl *Kubelet) newActionHandler(handler *api.Handler) actionHandler {
switch {
case handler.Exec != nil:
return &execActionHandler{kubelet: kl}
case handler.HTTPGet != nil:
return &httpActionHandler{client: kl.httpClient, kubelet: kl}
default:
glog.Errorf("Invalid handler: %v", handler)
return nil
}
}
func (kl *Kubelet) runHandler(podFullName string, uid types.UID, container *api.Container, handler *api.Handler) error {
actionHandler := kl.newActionHandler(handler)
if actionHandler == nil {
return fmt.Errorf("invalid handler")
}
return actionHandler.Run(podFullName, uid, container, handler)
}
// fieldPath returns a fieldPath locating container within pod.
// Returns an error if the container isn't part of the pod.
func fieldPath(pod *api.BoundPod, container *api.Container) (string, error) {
for i := range pod.Spec.Containers {
here := &pod.Spec.Containers[i]
if here.Name == container.Name {
if here.Name == "" {
return fmt.Sprintf("spec.containers[%d]", i), nil
} else {
return fmt.Sprintf("spec.containers{%s}", here.Name), nil
}
}
}
return "", fmt.Errorf("container %#v not found in pod %#v", container, pod)
}
// containerRef returns an *api.ObjectReference which references the given container within the
// given pod. Returns an error if the reference can't be constructed or the container doesn't
// actually belong to the pod.
// TODO: Pods that came to us by static config or over HTTP have no selfLink set, which makes
// this fail and log an error. Figure out how we want to identify these pods to the rest of the
// system.
func containerRef(pod *api.BoundPod, container *api.Container) (*api.ObjectReference, error) {
fieldPath, err := fieldPath(pod, container)
if err != nil {
// TODO: figure out intelligent way to refer to containers that we implicitly
// start (like the pod infra container). This is not a good way, ugh.
fieldPath = "implicitly required container " + container.Name
}
ref, err := api.GetPartialReference(pod, fieldPath)
if err != nil {
return nil, err
}
return ref, nil
}
// setRef stores a reference to a pod's container, associating it with the given docker id.
func (kl *Kubelet) setRef(id dockertools.DockerID, ref *api.ObjectReference) {
kl.refLock.Lock()
defer kl.refLock.Unlock()
if kl.dockerIDToRef == nil {
kl.dockerIDToRef = map[dockertools.DockerID]*api.ObjectReference{}
}
kl.dockerIDToRef[id] = ref
}
// clearRef forgets the given docker id and its associated container reference.
func (kl *Kubelet) clearRef(id dockertools.DockerID) {
kl.refLock.Lock()
defer kl.refLock.Unlock()
delete(kl.dockerIDToRef, id)
}
// getRef returns the container reference of the given id, or (nil, false) if none is stored.
func (kl *Kubelet) getRef(id dockertools.DockerID) (ref *api.ObjectReference, ok bool) {
kl.refLock.RLock()
defer kl.refLock.RUnlock()
ref, ok = kl.dockerIDToRef[id]
return ref, ok
}
// Run a single container from a pod. Returns the docker container ID
func (kl *Kubelet) runContainer(pod *api.BoundPod, container *api.Container, podVolumes volumeMap, netMode, ipcMode string) (id dockertools.DockerID, err error) {
ref, err := containerRef(pod, container)
if err != nil {
glog.Errorf("Couldn't make a ref to pod %v, container %v: '%v'", pod.Name, container.Name, err)
}
envVariables, err := kl.makeEnvironmentVariables(pod.Namespace, container)
if err != nil {
return "", err
}
binds := makeBinds(pod, container, podVolumes)
exposedPorts, portBindings := makePortsAndBindings(container)
opts := docker.CreateContainerOptions{
Name: dockertools.BuildDockerName(pod.UID, GetPodFullName(pod), container),
Config: &docker.Config{
Cmd: container.Command,
Env: envVariables,
ExposedPorts: exposedPorts,
Hostname: pod.Name,
Image: container.Image,
Memory: container.Resources.Limits.Memory().Value(),
CPUShares: milliCPUToShares(container.Resources.Limits.Cpu().MilliValue()),
WorkingDir: container.WorkingDir,
},
}
dockerContainer, err := kl.dockerClient.CreateContainer(opts)
if err != nil {
if ref != nil {
record.Eventf(ref, "failed",
"Failed to create docker container with error: %v", err)
}
return "", err
}
// Remember this reference so we can report events about this container
if ref != nil {
kl.setRef(dockertools.DockerID(dockerContainer.ID), ref)
record.Eventf(ref, "created", "Created with docker id %v", dockerContainer.ID)
}
if len(container.TerminationMessagePath) != 0 {
p := kl.getPodContainerDir(pod.UID, container.Name)
if err := os.MkdirAll(p, 0750); err != nil {
glog.Errorf("Error on creating %q: %v", p, err)
} else {
containerLogPath := path.Join(p, dockerContainer.ID)
fs, err := os.Create(containerLogPath)
if err != nil {
// TODO: Clean up the previouly created dir? return the error?
glog.Errorf("Error on creating termination-log file %q: %v", containerLogPath, err)
} else {
fs.Close() // Close immediately; we're just doing a `touch` here
b := fmt.Sprintf("%s:%s", containerLogPath, container.TerminationMessagePath)
binds = append(binds, b)
}
}
}
privileged := false
if capabilities.Get().AllowPrivileged {
privileged = container.Privileged
} else if container.Privileged {
return "", fmt.Errorf("container requested privileged mode, but it is disallowed globally.")
}
capAdd, capDrop := makeCapabilites(container.Capabilities.Add, container.Capabilities.Drop)
hc := &docker.HostConfig{
PortBindings: portBindings,
Binds: binds,
NetworkMode: netMode,
IpcMode: ipcMode,
Privileged: privileged,
CapAdd: capAdd,
CapDrop: capDrop,
}
if pod.Spec.DNSPolicy == api.DNSClusterFirst {
if err := kl.applyClusterDNS(hc, pod); err != nil {
return "", err
}
}
err = kl.dockerClient.StartContainer(dockerContainer.ID, hc)
if err != nil {
if ref != nil {
record.Eventf(ref, "failed",
"Failed to start with docker id %v with error: %v", dockerContainer.ID, err)
}
return "", err
}
if ref != nil {
record.Eventf(ref, "started", "Started with docker id %v", dockerContainer.ID)
}
if container.Lifecycle != nil && container.Lifecycle.PostStart != nil {
handlerErr := kl.runHandler(GetPodFullName(pod), pod.UID, container, container.Lifecycle.PostStart)
if handlerErr != nil {
kl.killContainerByID(dockerContainer.ID, "")
return dockertools.DockerID(""), fmt.Errorf("failed to call event handler: %v", handlerErr)
}
}
return dockertools.DockerID(dockerContainer.ID), err
}
var masterServices = util.NewStringSet("kubernetes", "kubernetes-ro")
// getServiceEnvVarMap makes a map[string]string of env vars for services a pod in namespace ns should see
func (kl *Kubelet) getServiceEnvVarMap(ns string) (map[string]string, error) {
var (
serviceMap = make(map[string]api.Service)
m = make(map[string]string)
)
// Get all service resources from the master (via a cache),
// and populate them into service enviroment variables.
if kl.serviceLister == nil {
// Kubelets without masters (e.g. plain GCE ContainerVM) don't set env vars.
return m, nil
}
services, err := kl.serviceLister.List()
if err != nil {
return m, fmt.Errorf("failed to list services when setting up env vars.")
}
// project the services in namespace ns onto the master services
for _, service := range services.Items {
serviceName := service.Name
switch service.Namespace {
// for the case whether the master service namespace is the namespace the pod
// is in, the pod should receive all the services in the namespace.
//
// ordering of the case clauses below enforces this
case ns:
serviceMap[serviceName] = service
case kl.masterServiceNamespace:
if masterServices.Has(serviceName) {
_, exists := serviceMap[serviceName]
if !exists {
serviceMap[serviceName] = service
}
}
}
}
services.Items = []api.Service{}
for _, service := range serviceMap {
services.Items = append(services.Items, service)
}
for _, e := range envvars.FromServices(&services) {
m[e.Name] = e.Value
}
return m, nil
}
// Make the service environment variables for a pod in the given namespace.
func (kl *Kubelet) makeEnvironmentVariables(ns string, container *api.Container) ([]string, error) {
var result []string
// Note: These are added to the docker.Config, but are not included in the checksum computed
// by dockertools.BuildDockerName(...). That way, we can still determine whether an
// api.Container is already running by its hash. (We don't want to restart a container just
// because some service changed.)
//
// Note that there is a race between Kubelet seeing the pod and kubelet seeing the service.
// To avoid this users can: (1) wait between starting a service and starting; or (2) detect
// missing service env var and exit and be restarted; or (3) use DNS instead of env vars
// and keep trying to resolve the DNS name of the service (recommended).
serviceEnv, err := kl.getServiceEnvVarMap(ns)
if err != nil {
return result, err
}
for _, value := range container.Env {
// The code is in transition from using etcd+BoundPods to apiserver+Pods.
// So, the master may set service env vars, or kubelet may. In case both are doing
// it, we delete the key from the kubelet-generated ones so we don't have duplicate
// env vars.
// TODO: remove this net line once all platforms use apiserver+Pods.
delete(serviceEnv, value.Name)
result = append(result, fmt.Sprintf("%s=%s", value.Name, value.Value))
}
// Append remaining service env vars.
for k, v := range serviceEnv {
result = append(result, fmt.Sprintf("%s=%s", k, v))
}
return result, nil
}
func (kl *Kubelet) applyClusterDNS(hc *docker.HostConfig, pod *api.BoundPod) error {
// Get host DNS settings and append them to cluster DNS settings.
f, err := os.Open("/etc/resolv.conf")
if err != nil {
return err
}
defer f.Close()
hostDNS, hostSearch, err := parseResolvConf(f)
if err != nil {
return err
}
if kl.clusterDNS != nil {
hc.DNS = append([]string{kl.clusterDNS.String()}, hostDNS...)
}
if kl.clusterDomain != "" {
nsDomain := fmt.Sprintf("%s.%s", pod.Namespace, kl.clusterDomain)
hc.DNSSearch = append([]string{nsDomain, kl.clusterDomain}, hostSearch...)
}
return nil
}
// Returns the list of DNS servers and DNS search domains.
func parseResolvConf(reader io.Reader) (nameservers []string, searches []string, err error) {
file, err := ioutil.ReadAll(reader)
if err != nil {
return nil, nil, err
}
// Lines of the form "nameserver 1.2.3.4" accumulate.
nameservers = []string{}
// Lines of the form "search example.com" overrule - last one wins.
searches = []string{}
lines := strings.Split(string(file), "\n")
for l := range lines {
trimmed := strings.TrimSpace(lines[l])
if strings.HasPrefix(trimmed, "#") {
continue
}
fields := strings.Fields(trimmed)
if len(fields) == 0 {
continue
}
if fields[0] == "nameserver" {
nameservers = append(nameservers, fields[1:]...)
}
if fields[0] == "search" {
searches = fields[1:]
}
}
return nameservers, searches, nil
}
// Kill a docker container
func (kl *Kubelet) killContainer(dockerContainer *docker.APIContainers) error {
return kl.killContainerByID(dockerContainer.ID, dockerContainer.Names[0])
}
func (kl *Kubelet) killContainerByID(ID, name string) error {
glog.V(2).Infof("Killing container with id %q and name %q", ID, name)
kl.readiness.remove(ID)
err := kl.dockerClient.StopContainer(ID, 10)
if len(name) == 0 {
return err
}
ref, ok := kl.getRef(dockertools.DockerID(ID))
if !ok {
glog.Warningf("No ref for pod '%v' - '%v'", ID, name)
} else {
// TODO: pass reason down here, and state, or move this call up the stack.
record.Eventf(ref, "killing", "Killing %v - %v", ID, name)
}
return err
}
const (
PodInfraContainerImage = "kubernetes/pause:latest"
)
// 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.BoundPod) (dockertools.DockerID, error) {
var ports []api.ContainerPort
// Docker only exports ports from the pod infra container. Let's
// collect all of the relevant ports and export them.
for _, container := range pod.Spec.Containers {
ports = append(ports, container.Ports...)
}
container := &api.Container{
Name: dockertools.PodInfraContainerName,
Image: kl.podInfraContainerImage,
Ports: ports,
}
ref, err := containerRef(pod, container)
if err != nil {
glog.Errorf("Couldn't make a ref to pod %v, container %v: '%v'", pod.Name, container.Name, err)
}
// TODO: make this a TTL based pull (if image older than X policy, pull)
ok, err := kl.dockerPuller.IsImagePresent(container.Image)
if err != nil {
if ref != nil {
record.Eventf(ref, "failed", "Failed to inspect image %q", container.Image)
}
return "", err
}
if !ok {
if err := kl.pullImage(container.Image, ref); err != nil {
return "", err
}
}
if ref != nil {
record.Eventf(ref, "pulled", "Successfully pulled image %q", container.Image)
}
id, err := kl.runContainer(pod, container, nil, "", "")
if err != nil {
return "", err
}
// Set OOM score of POD container to lower than those of the other
// containers in the pod. This ensures that it is killed only as a last
// resort.
containerInfo, err := kl.dockerClient.InspectContainer(string(id))
if err != nil {
return "", err
}
// Ensure the PID actually exists, else we'll move ourselves.
if containerInfo.State.Pid == 0 {
return "", fmt.Errorf("failed to get init PID for Docker pod infra container %q", string(id))
}
return id, util.ApplyOomScoreAdj(containerInfo.State.Pid, podOomScoreAdj)
}
func (kl *Kubelet) pullImage(img string, ref *api.ObjectReference) error {
start := time.Now()
defer func() {
metrics.ImagePullLatency.Observe(metrics.SinceInMicroseconds(start))
}()
if err := kl.dockerPuller.Pull(img); err != nil {
if ref != nil {
record.Eventf(ref, "failed", "Failed to pull image %q", img)
}
return err
}
if ref != nil {
record.Eventf(ref, "pulled", "Successfully pulled image %q", img)
}
return nil
}
// Kill all containers in a pod. Returns the number of containers deleted and an error if one occurs.
func (kl *Kubelet) killContainersInPod(pod *api.BoundPod, dockerContainers dockertools.DockerContainers) (int, error) {
podFullName := GetPodFullName(pod)
count := 0
errs := make(chan error, len(pod.Spec.Containers))
wg := sync.WaitGroup{}
for _, container := range pod.Spec.Containers {
// TODO: Consider being more aggressive: kill all containers with this pod UID, period.
if dockerContainer, found, _ := dockerContainers.FindPodContainer(podFullName, pod.UID, container.Name); found {
count++
wg.Add(1)
go func() {
defer util.HandleCrash()
err := kl.killContainer(dockerContainer)
if err != nil {
glog.Errorf("Failed to delete container: %v; Skipping pod %q", err, podFullName)
errs <- err
}
wg.Done()
}()
}
}
wg.Wait()
close(errs)
if len(errs) > 0 {
errList := []error{}
for err := range errs {
errList = append(errList, err)
}
return -1, fmt.Errorf("failed to delete containers (%v)", errList)
}
return count, nil
}
type empty struct{}