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Scheduler changes to assume volume and pod together, and then bind

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volume and pod asynchronously afterwards. This will also make it easier
to migrate to the scheduler framework.
This commit is contained in:
Michelle Au 2018-08-17 17:45:51 -07:00
parent 37d46a1e3f
commit 01d83fa104
4 changed files with 55 additions and 135 deletions
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130
pkg/scheduler/scheduler.go
View File

@ -17,7 +17,6 @@ limitations under the License.
package scheduler
import (
"fmt"
"time"
"k8s.io/api/core/v1"
@ -184,10 +183,6 @@ func (sched *Scheduler) Run() {
return
}
if utilfeature.DefaultFeatureGate.Enabled(features.VolumeScheduling) {
go sched.config.VolumeBinder.Run(sched.bindVolumesWorker, sched.config.StopEverything)
}
go wait.Until(sched.scheduleOne, 0, sched.config.StopEverything)
}
@ -265,17 +260,12 @@ func (sched *Scheduler) preempt(preemptor *v1.Pod, scheduleErr error) (string, e
return nodeName, err
}
// assumeAndBindVolumes will update the volume cache and then asynchronously bind volumes if required.
//
// If volume binding is required, then the bind volumes routine will update the pod to send it back through
// the scheduler.
//
// Otherwise, return nil error and continue to assume the pod.
// assumeVolumes will update the volume cache with the chosen bindings
//
// This function modifies assumed if volume binding is required.
func (sched *Scheduler) assumeAndBindVolumes(assumed *v1.Pod, host string) error {
func (sched *Scheduler) assumeVolumes(assumed *v1.Pod, host string) (allBound bool, err error) {
if utilfeature.DefaultFeatureGate.Enabled(features.VolumeScheduling) {
allBound, bindingRequired, err := sched.config.VolumeBinder.Binder.AssumePodVolumes(assumed, host)
allBound, err = sched.config.VolumeBinder.Binder.AssumePodVolumes(assumed, host)
if err != nil {
sched.config.Error(assumed, err)
sched.config.Recorder.Eventf(assumed, v1.EventTypeWarning, "FailedScheduling", "AssumePodVolumes failed: %v", err)
@ -285,76 +275,38 @@ func (sched *Scheduler) assumeAndBindVolumes(assumed *v1.Pod, host string) error
Reason: "SchedulerError",
Message: err.Error(),
})
return err
}
if !allBound {
err = fmt.Errorf("Volume binding started, waiting for completion")
if bindingRequired {
if sched.config.Ecache != nil {
invalidPredicates := sets.NewString(predicates.CheckVolumeBindingPred)
sched.config.Ecache.InvalidatePredicates(invalidPredicates)
}
// bindVolumesWorker() will update the Pod object to put it back in the scheduler queue
sched.config.VolumeBinder.BindQueue.Add(assumed)
} else {
// We are just waiting for PV controller to finish binding, put it back in the
// scheduler queue
sched.config.Error(assumed, err)
sched.config.Recorder.Eventf(assumed, v1.EventTypeNormal, "FailedScheduling", "%v", err)
sched.config.PodConditionUpdater.Update(assumed, &v1.PodCondition{
Type: v1.PodScheduled,
Status: v1.ConditionFalse,
Reason: "VolumeBindingWaiting",
})
}
return err
// Invalidate ecache because assumed volumes could have affected the cached
// pvs for other pods
if sched.config.Ecache != nil {
invalidPredicates := sets.NewString(predicates.CheckVolumeBindingPred)
sched.config.Ecache.InvalidatePredicates(invalidPredicates)
}
}
return nil
return
}
// bindVolumesWorker() processes pods queued in assumeAndBindVolumes() and tries to
// make the API update for volume binding.
// This function runs forever until the volume BindQueue is closed.
func (sched *Scheduler) bindVolumesWorker() {
workFunc := func() bool {
keyObj, quit := sched.config.VolumeBinder.BindQueue.Get()
if quit {
return true
}
defer sched.config.VolumeBinder.BindQueue.Done(keyObj)
// bindVolumes will make the API update with the assumed bindings and wait until
// the PV controller has completely finished the binding operation.
//
// If binding errors, times out or gets undone, then an error will be returned to
// retry scheduling.
func (sched *Scheduler) bindVolumes(assumed *v1.Pod) error {
var reason string
var eventType string
assumed, ok := keyObj.(*v1.Pod)
if !ok {
glog.V(4).Infof("Object is not a *v1.Pod")
return false
glog.V(5).Infof("Trying to bind volumes for pod \"%v/%v\"", assumed.Namespace, assumed.Name)
err := sched.config.VolumeBinder.Binder.BindPodVolumes(assumed)
if err != nil {
glog.V(1).Infof("Failed to bind volumes for pod \"%v/%v\": %v", assumed.Namespace, assumed.Name, err)
// Unassume the Pod and retry scheduling
if forgetErr := sched.config.SchedulerCache.ForgetPod(assumed); forgetErr != nil {
glog.Errorf("scheduler cache ForgetPod failed: %v", forgetErr)
}
// TODO: add metrics
var reason string
var eventType string
glog.V(5).Infof("Trying to bind volumes for pod \"%v/%v\"", assumed.Namespace, assumed.Name)
// The Pod is always sent back to the scheduler afterwards.
err := sched.config.VolumeBinder.Binder.BindPodVolumes(assumed)
if err != nil {
glog.V(1).Infof("Failed to bind volumes for pod \"%v/%v\": %v", assumed.Namespace, assumed.Name, err)
reason = "VolumeBindingFailed"
eventType = v1.EventTypeWarning
} else {
glog.V(4).Infof("Successfully bound volumes for pod \"%v/%v\"", assumed.Namespace, assumed.Name)
reason = "VolumeBindingWaiting"
eventType = v1.EventTypeNormal
err = fmt.Errorf("Volume binding started, waiting for completion")
}
// Always fail scheduling regardless of binding success.
// The Pod needs to be sent back through the scheduler to:
// * Retry volume binding if it fails.
// * Retry volume binding if dynamic provisioning fails.
// * Bind the Pod to the Node once all volumes are bound.
reason = "VolumeBindingFailed"
eventType = v1.EventTypeWarning
sched.config.Error(assumed, err)
sched.config.Recorder.Eventf(assumed, eventType, "FailedScheduling", "%v", err)
sched.config.PodConditionUpdater.Update(assumed, &v1.PodCondition{
@ -362,15 +314,11 @@ func (sched *Scheduler) bindVolumesWorker() {
Status: v1.ConditionFalse,
Reason: reason,
})
return false
return err
}
for {
if quit := workFunc(); quit {
glog.V(4).Infof("bindVolumesWorker shutting down")
break
}
}
glog.V(5).Infof("Success binding volumes for pod \"%v/%v\"", assumed.Namespace, assumed.Name)
return nil
}
// assume signals to the cache that a pod is already in the cache, so that binding can be asynchronous.
@ -478,16 +426,12 @@ func (sched *Scheduler) scheduleOne() {
// Assume volumes first before assuming the pod.
//
// If no volumes need binding, then nil is returned, and continue to assume the pod.
// If all volumes are completely bound, then allBound is true and binding will be skipped.
//
// Otherwise, error is returned and volume binding is started asynchronously for all of the pod's volumes.
// scheduleOne() returns immediately on error, so that it doesn't continue to assume the pod.
//
// After the asynchronous volume binding updates are made, it will send the pod back through the scheduler for
// subsequent passes until all volumes are fully bound.
// Otherwise, binding of volumes is started after the pod is assumed, but before pod binding.
//
// This function modifies 'assumedPod' if volume binding is required.
err = sched.assumeAndBindVolumes(assumedPod, suggestedHost)
allBound, err := sched.assumeVolumes(assumedPod, suggestedHost)
if err != nil {
return
}
@ -499,6 +443,14 @@ func (sched *Scheduler) scheduleOne() {
}
// bind the pod to its host asynchronously (we can do this b/c of the assumption step above).
go func() {
// Bind volumes first before Pod
if !allBound {
err = sched.bindVolumes(assumedPod)
if err != nil {
return
}
}
err := sched.bind(assumedPod, &v1.Binding{
ObjectMeta: metav1.ObjectMeta{Namespace: assumedPod.Namespace, Name: assumedPod.Name, UID: assumedPod.UID},
Target: v1.ObjectReference{

35
pkg/scheduler/scheduler_test.go
View File

@ -707,8 +707,7 @@ func TestSchedulerWithVolumeBinding(t *testing.T) {
},
expectAssumeCalled: true,
expectPodBind: &v1.Binding{ObjectMeta: metav1.ObjectMeta{Name: "foo", UID: types.UID("foo")}, Target: v1.ObjectReference{Kind: "Node", Name: "machine1"}},
eventReason: "Scheduled",
eventReason: "Scheduled",
},
{
name: "bound/invalid pv affinity",
@ -739,28 +738,15 @@ func TestSchedulerWithVolumeBinding(t *testing.T) {
expectError: makePredicateError("1 node(s) didn't find available persistent volumes to bind, 1 node(s) had volume node affinity conflict"),
},
{
name: "unbound/found matches",
name: "unbound/found matches/bind succeeds",
volumeBinderConfig: &persistentvolume.FakeVolumeBinderConfig{
FindUnboundSatsified: true,
FindBoundSatsified: true,
AssumeBindingRequired: true,
FindUnboundSatsified: true,
FindBoundSatsified: true,
},
expectAssumeCalled: true,
expectBindCalled: true,
eventReason: "FailedScheduling",
expectError: fmt.Errorf("Volume binding started, waiting for completion"),
},
{
name: "unbound/found matches/already-bound",
volumeBinderConfig: &persistentvolume.FakeVolumeBinderConfig{
FindUnboundSatsified: true,
FindBoundSatsified: true,
AssumeBindingRequired: false,
},
expectAssumeCalled: true,
expectBindCalled: false,
eventReason: "FailedScheduling",
expectError: fmt.Errorf("Volume binding started, waiting for completion"),
expectPodBind: &v1.Binding{ObjectMeta: metav1.ObjectMeta{Name: "foo", UID: types.UID("foo")}, Target: v1.ObjectReference{Kind: "Node", Name: "machine1"}},
eventReason: "Scheduled",
},
{
name: "predicate error",
@ -784,10 +770,9 @@ func TestSchedulerWithVolumeBinding(t *testing.T) {
{
name: "bind error",
volumeBinderConfig: &persistentvolume.FakeVolumeBinderConfig{
FindUnboundSatsified: true,
FindBoundSatsified: true,
AssumeBindingRequired: true,
BindErr: bindErr,
FindUnboundSatsified: true,
FindBoundSatsified: true,
BindErr: bindErr,
},
expectAssumeCalled: true,
expectBindCalled: true,
@ -814,8 +799,6 @@ func TestSchedulerWithVolumeBinding(t *testing.T) {
close(eventChan)
})
go fakeVolumeBinder.Run(s.bindVolumesWorker, stop)
s.scheduleOne()
// Wait for pod to succeed or fail scheduling

2
pkg/scheduler/volumebinder/BUILD
View File

@ -8,11 +8,9 @@ go_library(
deps = [
"//pkg/controller/volume/persistentvolume:go_default_library",
"//staging/src/k8s.io/api/core/v1:go_default_library",
"//staging/src/k8s.io/apimachinery/pkg/util/wait:go_default_library",
"//staging/src/k8s.io/client-go/informers/core/v1:go_default_library",
"//staging/src/k8s.io/client-go/informers/storage/v1:go_default_library",
"//staging/src/k8s.io/client-go/kubernetes:go_default_library",
"//staging/src/k8s.io/client-go/util/workqueue:go_default_library",
],
)

23
pkg/scheduler/volumebinder/volume_binder.go
View File

@ -20,19 +20,15 @@ import (
"time"
"k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/util/wait"
coreinformers "k8s.io/client-go/informers/core/v1"
storageinformers "k8s.io/client-go/informers/storage/v1"
clientset "k8s.io/client-go/kubernetes"
"k8s.io/client-go/util/workqueue"
"k8s.io/kubernetes/pkg/controller/volume/persistentvolume"
)
// VolumeBinder sets up the volume binding library and manages
// the volume binding operations with a queue.
// VolumeBinder sets up the volume binding library
type VolumeBinder struct {
Binder persistentvolume.SchedulerVolumeBinder
BindQueue *workqueue.Type
Binder persistentvolume.SchedulerVolumeBinder
}
// NewVolumeBinder sets up the volume binding library and binding queue
@ -43,27 +39,18 @@ func NewVolumeBinder(
storageClassInformer storageinformers.StorageClassInformer) *VolumeBinder {
return &VolumeBinder{
Binder: persistentvolume.NewVolumeBinder(client, pvcInformer, pvInformer, storageClassInformer),
BindQueue: workqueue.NewNamed("podsToBind"),
// TODO: what is a good bind timeout value?
Binder: persistentvolume.NewVolumeBinder(client, pvcInformer, pvInformer, storageClassInformer, 10*time.Minute),
}
}
// NewFakeVolumeBinder sets up a fake volume binder and binding queue
func NewFakeVolumeBinder(config *persistentvolume.FakeVolumeBinderConfig) *VolumeBinder {
return &VolumeBinder{
Binder: persistentvolume.NewFakeVolumeBinder(config),
BindQueue: workqueue.NewNamed("podsToBind"),
Binder: persistentvolume.NewFakeVolumeBinder(config),
}
}
// Run starts a goroutine to handle the binding queue with the given function.
func (b *VolumeBinder) Run(bindWorkFunc func(), stopCh <-chan struct{}) {
go wait.Until(bindWorkFunc, time.Second, stopCh)
<-stopCh
b.BindQueue.ShutDown()
}
// DeletePodBindings will delete the cached volume bindings for the given pod.
func (b *VolumeBinder) DeletePodBindings(pod *v1.Pod) {
cache := b.Binder.GetBindingsCache()