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Merge pull request #27229 from pmorie/pod-manager-godoc 

Automatic merge from submit-queue

Godoc for kubelet pod manager

Improve godoc for pod manager and mirror client.

@kubernetes/sig-node
pull/6/head
k8s-merge-robot 2016-06-17 08:15:58 -07:00 committed by GitHub
parent 7edb84c2eb 8dafc776de
commit fd7803cdbb
2 changed files with 65 additions and 41 deletions
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86
pkg/kubelet/pod/manager.go
View File

@ -24,49 +24,79 @@ import (
"k8s.io/kubernetes/pkg/types"
)
// Pod manager stores and manages access to the pods.
// Manager stores and manages access to pods, maintaining the mappings
// between static pods and mirror pods.
//
// Kubelet discovers pod updates from 3 sources: file, http, and apiserver.
// Pods from non-apiserver sources are called static pods, and API server is
// not aware of the existence of static pods. In order to monitor the status of
// such pods, kubelet creates a mirror pod for each static pod via the API
// server.
// The kubelet discovers pod updates from 3 sources: file, http, and
// apiserver. Pods from non-apiserver sources are called static pods, and API
// server is not aware of the existence of static pods. In order to monitor
// the status of such pods, the kubelet creates a mirror pod for each static
// pod via the API server.
//
// A mirror pod has the same pod full name (name and namespace) as its static
// counterpart (albeit different metadata such as UID, etc). By leveraging the
// fact that kubelet reports the pod status using the pod full name, the status
// of the mirror pod always reflects the actual status of the static pod.
// When a static pod gets deleted, the associated orphaned mirror pod will
// also be removed.
// fact that the kubelet reports the pod status using the pod full name, the
// status of the mirror pod always reflects the actual status of the static
// pod. When a static pod gets deleted, the associated orphaned mirror pod
// will also be removed.
type Manager interface {
// GetPods returns the regular pods bound to the kubelet and their spec.
GetPods() []*api.Pod
// GetPodByName returns the (non-mirror) pod that matches full name, as well as
// whether the pod was found.
GetPodByFullName(podFullName string) (*api.Pod, bool)
// GetPodByName provides the (non-mirror) pod that matches namespace and
// name, as well as whether the pod was found.
GetPodByName(namespace, name string) (*api.Pod, bool)
// GetPodByUID provides the (non-mirror) pod that matches pod UID, as well as
// whether the pod is found.
GetPodByUID(types.UID) (*api.Pod, bool)
// GetPodByMirrorPod returns the static pod for the given mirror pod and
// whether it was known to the pod manger.
GetPodByMirrorPod(*api.Pod) (*api.Pod, bool)
// GetMirrorPodByPod returns the mirror pod for the given static pod and
// whether it was known to the pod manager.
GetMirrorPodByPod(*api.Pod) (*api.Pod, bool)
// GetPodsAndMirrorPods returns the both regular and mirror pods.
GetPodsAndMirrorPods() ([]*api.Pod, []*api.Pod)
// SetPods replaces the internal pods with the new pods.
// It is currently only used for testing.
SetPods(pods []*api.Pod)
// Methods that modify a single pod.
// AddPod adds the given pod to the manager.
AddPod(pod *api.Pod)
// UpdatePod updates the given pod in the manager.
UpdatePod(pod *api.Pod)
// DeletePod deletes the given pod from the manager. For mirror pods,
// this means deleting the mappings related to mirror pods. For non-
// mirror pods, this means deleting from indexes for all non-mirror pods.
DeletePod(pod *api.Pod)
// DeleteOrphanedMirrorPods deletes all mirror pods which do not have
// associated static pods. This method sends deletion requests to the API
// server, but does NOT modify the internal pod storage in basicManager.
DeleteOrphanedMirrorPods()
// TranslatePodUID returns the UID which is the mirror pod or static pod
// of the pod with the given UID. If the UID belongs to a mirror pod,
// returns the UID of its static pod. If the UID belongs to a static pod,
// returns the UID of its mirror pod. Otherwise, returns the original UID.
//
// All public-facing functions should perform this translation for UIDs
// because user may provide a mirror pod UID, which is not recognized by
// internal Kubelet functions.
TranslatePodUID(uid types.UID) types.UID
// GetUIDTranslations returns the mappings of static pod UIDs to mirror pod
// UIDs and mirror pod UIDs to static pod UIDs.
GetUIDTranslations() (podToMirror, mirrorToPod map[types.UID]types.UID)
// IsMirrorPodOf returns true if mirrorPod is a correct representation of
// pod; false otherwise.
IsMirrorPodOf(mirrorPod, pod *api.Pod) bool
MirrorClient
}
// All maps in basicManager should be set by calling UpdatePods();
// individual arrays/maps are not immutable and no other methods should attempt
// to modify them.
// basicManager is a functional Manger.
//
// All fields in basicManager are read-only and are updated calling SetPods,
// AddPod, UpdatePod, or DeletePod.
type basicManager struct {
// Protects all internal maps.
lock sync.RWMutex
@ -87,6 +117,7 @@ type basicManager struct {
MirrorClient
}
// NewBasicPodManager returns a functional Manager.
func NewBasicPodManager(client MirrorClient) Manager {
pm := &basicManager{}
pm.MirrorClient = client
@ -118,6 +149,9 @@ func (pm *basicManager) UpdatePod(pod *api.Pod) {
pm.updatePodsInternal(pod)
}
// updatePodsInternal replaces the given pods in the current state of the
// manager, updating the various indices. The caller is assumed to hold the
// lock.
func (pm *basicManager) updatePodsInternal(pods ...*api.Pod) {
for _, pod := range pods {
podFullName := kubecontainer.GetPodFullName(pod)
@ -151,14 +185,12 @@ func (pm *basicManager) DeletePod(pod *api.Pod) {
}
}
// GetPods returns the regular pods bound to the kubelet and their spec.
func (pm *basicManager) GetPods() []*api.Pod {
pm.lock.RLock()
defer pm.lock.RUnlock()
return podsMapToPods(pm.podByUID)
}
// GetPodsAndMirrorPods returns the both regular and mirror pods.
func (pm *basicManager) GetPodsAndMirrorPods() ([]*api.Pod, []*api.Pod) {
pm.lock.RLock()
defer pm.lock.RUnlock()
@ -172,8 +204,6 @@ func (pm *basicManager) getAllPods() []*api.Pod {
return append(podsMapToPods(pm.podByUID), podsMapToPods(pm.mirrorPodByUID)...)
}
// GetPodByUID provides the (non-mirror) pod that matches pod UID, as well as
// whether the pod is found.
func (pm *basicManager) GetPodByUID(uid types.UID) (*api.Pod, bool) {
pm.lock.RLock()
defer pm.lock.RUnlock()
@ -181,15 +211,11 @@ func (pm *basicManager) GetPodByUID(uid types.UID) (*api.Pod, bool) {
return pod, ok
}
// GetPodByName provides the (non-mirror) pod that matches namespace and name,
// as well as whether the pod was found.
func (pm *basicManager) GetPodByName(namespace, name string) (*api.Pod, bool) {
podFullName := kubecontainer.BuildPodFullName(name, namespace)
return pm.GetPodByFullName(podFullName)
}
// GetPodByName returns the (non-mirror) pod that matches full name, as well as
// whether the pod was found.
func (pm *basicManager) GetPodByFullName(podFullName string) (*api.Pod, bool) {
pm.lock.RLock()
defer pm.lock.RUnlock()
@ -197,10 +223,6 @@ func (pm *basicManager) GetPodByFullName(podFullName string) (*api.Pod, bool) {
return pod, ok
}
// If the UID belongs to a mirror pod, maps it to the UID of its static pod.
// Otherwise, return the original UID. All public-facing functions should
// perform this translation for UIDs because user may provide a mirror pod UID,
// which is not recognized by internal Kubelet functions.
func (pm *basicManager) TranslatePodUID(uid types.UID) types.UID {
if uid == "" {
return uid
@ -239,9 +261,6 @@ func (pm *basicManager) getOrphanedMirrorPodNames() []string {
return podFullNames
}
// Delete all mirror pods which do not have associated static pods. This method
// sends deletion requets to the API server, but does NOT modify the internal
// pod storage in basicManager.
func (pm *basicManager) DeleteOrphanedMirrorPods() {
podFullNames := pm.getOrphanedMirrorPodNames()
for _, podFullName := range podFullNames {
@ -249,7 +268,6 @@ func (pm *basicManager) DeleteOrphanedMirrorPods() {
}
}
// Returns true if mirrorPod is a correct representation of pod; false otherwise.
func (pm *basicManager) IsMirrorPodOf(mirrorPod, pod *api.Pod) bool {
// Check name and namespace first.
if pod.Name != mirrorPod.Name || pod.Namespace != mirrorPod.Namespace {

20
pkg/kubelet/pod/mirror_client.go
View File

@ -25,23 +25,30 @@ import (
kubetypes "k8s.io/kubernetes/pkg/kubelet/types"
)
// Mirror client is used to create/delete a mirror pod.
// MirrorClient knows how to create/delete a mirror pod in the API server.
type MirrorClient interface {
CreateMirrorPod(*api.Pod) error
DeleteMirrorPod(string) error
// CreateMirrorPod creates a mirror pod in the API server for the given
// pod or returns an error. The mirror pod will have the same annotations
// as the given pod as well as an extra annotation containing the hash of
// the static pod.
CreateMirrorPod(pod *api.Pod) error
// DeleteMirrorPod deletes the mirror pod with the given full name from
// the API server or returns an error.
DeleteMirrorPod(podFullName string) error
}
// basicMirrorClient is a functional MirrorClient. Mirror pods are stored in
// the kubelet directly because they need to be in sync with the internal
// pods.
type basicMirrorClient struct {
// mirror pods are stored in the kubelet directly because they need to be
// in sync with the internal pods.
apiserverClient clientset.Interface
}
// NewBasicMirrorClient returns a new MirrorClient.
func NewBasicMirrorClient(apiserverClient clientset.Interface) MirrorClient {
return &basicMirrorClient{apiserverClient: apiserverClient}
}
// Creates a mirror pod.
func (mc *basicMirrorClient) CreateMirrorPod(pod *api.Pod) error {
if mc.apiserverClient == nil {
return nil
@ -65,7 +72,6 @@ func (mc *basicMirrorClient) CreateMirrorPod(pod *api.Pod) error {
return err
}
// Deletes a mirror pod.
func (mc *basicMirrorClient) DeleteMirrorPod(podFullName string) error {
if mc.apiserverClient == nil {
return nil