forked from kubernetes/kubernetes
-
Notifications
You must be signed in to change notification settings - Fork 14
/
plugin.go
893 lines (788 loc) · 29.8 KB
/
plugin.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
/*
Copyright 2015 The Kubernetes Authors 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 scheduler
import (
"fmt"
"io"
"net/http"
"strconv"
"sync"
"time"
log "github.com/golang/glog"
mesos "github.com/mesos/mesos-go/mesosproto"
mutil "github.com/mesos/mesos-go/mesosutil"
"k8s.io/kubernetes/contrib/mesos/pkg/backoff"
"k8s.io/kubernetes/contrib/mesos/pkg/offers"
"k8s.io/kubernetes/contrib/mesos/pkg/queue"
"k8s.io/kubernetes/contrib/mesos/pkg/runtime"
annotation "k8s.io/kubernetes/contrib/mesos/pkg/scheduler/meta"
"k8s.io/kubernetes/contrib/mesos/pkg/scheduler/podtask"
"k8s.io/kubernetes/pkg/api"
"k8s.io/kubernetes/pkg/api/errors"
"k8s.io/kubernetes/pkg/client/cache"
"k8s.io/kubernetes/pkg/client/record"
client "k8s.io/kubernetes/pkg/client/unversioned"
"k8s.io/kubernetes/pkg/fields"
"k8s.io/kubernetes/pkg/util"
plugin "k8s.io/kubernetes/plugin/pkg/scheduler"
"k8s.io/kubernetes/plugin/pkg/scheduler/algorithm"
)
const (
enqueuePopTimeout = 200 * time.Millisecond
enqueueWaitTimeout = 1 * time.Second
yieldPopTimeout = 200 * time.Millisecond
yieldWaitTimeout = 1 * time.Second
pluginRecoveryDelay = 100 * time.Millisecond // delay after scheduler plugin crashes, before we resume scheduling
)
// scheduler abstraction to allow for easier unit testing
type schedulerInterface interface {
sync.Locker // synchronize scheduler plugin operations
SlaveIndex
algorithm() PodScheduler
offers() offers.Registry
tasks() podtask.Registry
// driver calls
killTask(taskId string) error
launchTask(*podtask.T) error
// convenience
createPodTask(api.Context, *api.Pod) (*podtask.T, error)
}
type k8smScheduler struct {
sync.Mutex
internal *KubernetesScheduler
}
func (k *k8smScheduler) algorithm() PodScheduler {
return k.internal
}
func (k *k8smScheduler) offers() offers.Registry {
return k.internal.offers
}
func (k *k8smScheduler) tasks() podtask.Registry {
return k.internal.taskRegistry
}
func (k *k8smScheduler) createPodTask(ctx api.Context, pod *api.Pod) (*podtask.T, error) {
return podtask.New(ctx, "", *pod, k.internal.executor)
}
func (k *k8smScheduler) slaveHostNameFor(id string) string {
return k.internal.slaveHostNames.HostName(id)
}
func (k *k8smScheduler) killTask(taskId string) error {
killTaskId := mutil.NewTaskID(taskId)
_, err := k.internal.driver.KillTask(killTaskId)
return err
}
func (k *k8smScheduler) launchTask(task *podtask.T) error {
// assume caller is holding scheduler lock
taskList := []*mesos.TaskInfo{task.BuildTaskInfo()}
offerIds := []*mesos.OfferID{task.Offer.Details().Id}
filters := &mesos.Filters{}
_, err := k.internal.driver.LaunchTasks(offerIds, taskList, filters)
return err
}
type binder struct {
api schedulerInterface
}
// implements binding.Registry, launches the pod-associated-task in mesos
func (b *binder) Bind(binding *api.Binding) error {
ctx := api.WithNamespace(api.NewContext(), binding.Namespace)
// default upstream scheduler passes pod.Name as binding.Name
podKey, err := podtask.MakePodKey(ctx, binding.Name)
if err != nil {
return err
}
b.api.Lock()
defer b.api.Unlock()
switch task, state := b.api.tasks().ForPod(podKey); state {
case podtask.StatePending:
return b.bind(ctx, binding, task)
default:
// in this case it's likely that the pod has been deleted between Schedule
// and Bind calls
log.Infof("No pending task for pod %s", podKey)
return noSuchPodErr //TODO(jdef) this error is somewhat misleading since the task could be running?!
}
}
func (b *binder) rollback(task *podtask.T, err error) error {
task.Offer.Release()
task.Reset()
if err2 := b.api.tasks().Update(task); err2 != nil {
log.Errorf("failed to update pod task: %v", err2)
}
return err
}
// assumes that: caller has acquired scheduler lock and that the task is still pending
//
// bind does not actually do the binding itself, but launches the pod as a Mesos task. The
// kubernetes executor on the slave will finally do the binding. This is different from the
// upstream scheduler in the sense that the upstream scheduler does the binding and the
// kubelet will notice that and launches the pod.
func (b *binder) bind(ctx api.Context, binding *api.Binding, task *podtask.T) (err error) {
// sanity check: ensure that the task hasAcceptedOffer(), it's possible that between
// Schedule() and now that the offer for this task was rescinded or invalidated.
// ((we should never see this here))
if !task.HasAcceptedOffer() {
return fmt.Errorf("task has not accepted a valid offer %v", task.ID)
}
// By this time, there is a chance that the slave is disconnected.
offerId := task.GetOfferId()
if offer, ok := b.api.offers().Get(offerId); !ok || offer.HasExpired() {
// already rescinded or timed out or otherwise invalidated
return b.rollback(task, fmt.Errorf("failed prior to launchTask due to expired offer for task %v", task.ID))
}
if err = b.prepareTaskForLaunch(ctx, binding.Target.Name, task, offerId); err == nil {
log.V(2).Infof("launching task: %q on target %q slave %q for pod \"%v/%v\", cpu %.2f, mem %.2f MB",
task.ID, binding.Target.Name, task.Spec.SlaveID, task.Pod.Namespace, task.Pod.Name, task.Spec.CPU, task.Spec.Memory)
if err = b.api.launchTask(task); err == nil {
b.api.offers().Invalidate(offerId)
task.Set(podtask.Launched)
if err = b.api.tasks().Update(task); err != nil {
// this should only happen if the task has been removed or has changed status,
// which SHOULD NOT HAPPEN as long as we're synchronizing correctly
log.Errorf("failed to update task w/ Launched status: %v", err)
}
return
}
}
return b.rollback(task, fmt.Errorf("Failed to launch task %v: %v", task.ID, err))
}
//TODO(jdef) unit test this, ensure that task's copy of api.Pod is not modified
func (b *binder) prepareTaskForLaunch(ctx api.Context, machine string, task *podtask.T, offerId string) error {
pod := task.Pod
// we make an effort here to avoid making changes to the task's copy of the pod, since
// we want that to reflect the initial user spec, and not the modified spec that we
// build for the executor to consume.
oemCt := pod.Spec.Containers
pod.Spec.Containers = append([]api.Container{}, oemCt...) // (shallow) clone before mod
if pod.Annotations == nil {
pod.Annotations = make(map[string]string)
}
task.SaveRecoveryInfo(pod.Annotations)
pod.Annotations[annotation.BindingHostKey] = task.Spec.AssignedSlave
for _, entry := range task.Spec.PortMap {
oemPorts := pod.Spec.Containers[entry.ContainerIdx].Ports
ports := append([]api.ContainerPort{}, oemPorts...)
p := &ports[entry.PortIdx]
p.HostPort = int(entry.OfferPort)
op := strconv.FormatUint(entry.OfferPort, 10)
pod.Annotations[fmt.Sprintf(annotation.PortMappingKeyFormat, p.Protocol, p.ContainerPort)] = op
if p.Name != "" {
pod.Annotations[fmt.Sprintf(annotation.PortNameMappingKeyFormat, p.Protocol, p.Name)] = op
}
pod.Spec.Containers[entry.ContainerIdx].Ports = ports
}
// the kubelet-executor uses this to instantiate the pod
log.V(3).Infof("prepared pod spec: %+v", pod)
data, err := api.Codec.Encode(&pod)
if err != nil {
log.V(2).Infof("Failed to marshal the pod spec: %v", err)
return err
}
task.Spec.Data = data
return nil
}
type kubeScheduler struct {
api schedulerInterface
podUpdates queue.FIFO
}
// recoverAssignedSlave recovers the assigned Mesos slave from a pod by searching
// the BindingHostKey. For tasks in the registry of the scheduler, the same
// value is stored in T.Spec.AssignedSlave. Before launching, the BindingHostKey
// annotation is added and the executor will eventually persist that to the
// apiserver on binding.
func recoverAssignedSlave(pod *api.Pod) string {
return pod.Annotations[annotation.BindingHostKey]
}
// Schedule implements the Scheduler interface of Kubernetes.
// It returns the selectedMachine's name and error (if there's any).
func (k *kubeScheduler) Schedule(pod *api.Pod, unused algorithm.NodeLister) (string, error) {
log.Infof("Try to schedule pod %v\n", pod.Name)
ctx := api.WithNamespace(api.NewDefaultContext(), pod.Namespace)
// default upstream scheduler passes pod.Name as binding.PodID
podKey, err := podtask.MakePodKey(ctx, pod.Name)
if err != nil {
return "", err
}
k.api.Lock()
defer k.api.Unlock()
switch task, state := k.api.tasks().ForPod(podKey); state {
case podtask.StateUnknown:
// There's a bit of a potential race here, a pod could have been yielded() and
// then before we get *here* it could be deleted.
// We use meta to index the pod in the store since that's what k8s reflector does.
podName, err := cache.MetaNamespaceKeyFunc(pod)
if err != nil {
log.Warningf("aborting Schedule, unable to understand pod object %+v", pod)
return "", noSuchPodErr
}
if deleted := k.podUpdates.Poll(podName, queue.DELETE_EVENT); deleted {
// avoid scheduling a pod that's been deleted between yieldPod() and Schedule()
log.Infof("aborting Schedule, pod has been deleted %+v", pod)
return "", noSuchPodErr
}
return k.doSchedule(k.api.tasks().Register(k.api.createPodTask(ctx, pod)))
//TODO(jdef) it's possible that the pod state has diverged from what
//we knew previously, we should probably update the task.Pod state here
//before proceeding with scheduling
case podtask.StatePending:
if pod.UID != task.Pod.UID {
// we're dealing with a brand new pod spec here, so the old one must have been
// deleted -- and so our task store is out of sync w/ respect to reality
//TODO(jdef) reconcile task
return "", fmt.Errorf("task %v spec is out of sync with pod %v spec, aborting schedule", task.ID, pod.Name)
} else if task.Has(podtask.Launched) {
// task has been marked as "launched" but the pod binding creation may have failed in k8s,
// but we're going to let someone else handle it, probably the mesos task error handler
return "", fmt.Errorf("task %s has already been launched, aborting schedule", task.ID)
} else {
return k.doSchedule(task, nil)
}
default:
return "", fmt.Errorf("task %s is not pending, nothing to schedule", task.ID)
}
}
// Call ScheduleFunc and subtract some resources, returning the name of the machine the task is scheduled on
func (k *kubeScheduler) doSchedule(task *podtask.T, err error) (string, error) {
var offer offers.Perishable
if task.HasAcceptedOffer() {
// verify that the offer is still on the table
offerId := task.GetOfferId()
if offer, ok := k.api.offers().Get(offerId); ok && !offer.HasExpired() {
// skip tasks that have already have assigned offers
offer = task.Offer
} else {
task.Offer.Release()
task.Reset()
if err = k.api.tasks().Update(task); err != nil {
return "", err
}
}
}
if err == nil && offer == nil {
offer, err = k.api.algorithm().SchedulePod(k.api.offers(), k.api, task)
}
if err != nil {
return "", err
}
details := offer.Details()
if details == nil {
return "", fmt.Errorf("offer already invalid/expired for task %v", task.ID)
}
slaveId := details.GetSlaveId().GetValue()
if slaveHostName := k.api.slaveHostNameFor(slaveId); slaveHostName == "" {
// not much sense in Release()ing the offer here since its owner died
offer.Release()
k.api.offers().Invalidate(details.Id.GetValue())
return "", fmt.Errorf("Slave disappeared (%v) while scheduling task %v", slaveId, task.ID)
} else {
if task.Offer != nil && task.Offer != offer {
return "", fmt.Errorf("task.offer assignment must be idempotent, task %+v: offer %+v", task, offer)
}
task.Offer = offer
k.api.algorithm().Procurement()(task, details) // TODO(jdef) why is nothing checking the error returned here?
if err := k.api.tasks().Update(task); err != nil {
offer.Release()
return "", err
}
return slaveHostName, nil
}
}
type queuer struct {
lock sync.Mutex // shared by condition variables of this struct
podUpdates queue.FIFO // queue of pod updates to be processed
podQueue *queue.DelayFIFO // queue of pods to be scheduled
deltaCond sync.Cond // pod changes are available for processing
unscheduledCond sync.Cond // there are unscheduled pods for processing
}
func newQueuer(store queue.FIFO) *queuer {
q := &queuer{
podQueue: queue.NewDelayFIFO(),
podUpdates: store,
}
q.deltaCond.L = &q.lock
q.unscheduledCond.L = &q.lock
return q
}
func (q *queuer) installDebugHandlers(mux *http.ServeMux) {
mux.HandleFunc("/debug/scheduler/podqueue", func(w http.ResponseWriter, r *http.Request) {
for _, x := range q.podQueue.List() {
if _, err := io.WriteString(w, fmt.Sprintf("%+v\n", x)); err != nil {
break
}
}
})
mux.HandleFunc("/debug/scheduler/podstore", func(w http.ResponseWriter, r *http.Request) {
for _, x := range q.podUpdates.List() {
if _, err := io.WriteString(w, fmt.Sprintf("%+v\n", x)); err != nil {
break
}
}
})
}
// signal that there are probably pod updates waiting to be processed
func (q *queuer) updatesAvailable() {
q.deltaCond.Broadcast()
}
// delete a pod from the to-be-scheduled queue
func (q *queuer) dequeue(id string) {
q.podQueue.Delete(id)
}
// re-add a pod to the to-be-scheduled queue, will not overwrite existing pod data (that
// may have already changed).
func (q *queuer) requeue(pod *Pod) {
// use KeepExisting in case the pod has already been updated (can happen if binding fails
// due to constraint voilations); we don't want to overwrite a newer entry with stale data.
q.podQueue.Add(pod, queue.KeepExisting)
q.unscheduledCond.Broadcast()
}
// same as requeue but calls podQueue.Offer instead of podQueue.Add
func (q *queuer) reoffer(pod *Pod) {
// use KeepExisting in case the pod has already been updated (can happen if binding fails
// due to constraint voilations); we don't want to overwrite a newer entry with stale data.
if q.podQueue.Offer(pod, queue.KeepExisting) {
q.unscheduledCond.Broadcast()
}
}
// spawns a go-routine to watch for unscheduled pods and queue them up
// for scheduling. returns immediately.
func (q *queuer) Run(done <-chan struct{}) {
go runtime.Until(func() {
log.Info("Watching for newly created pods")
q.lock.Lock()
defer q.lock.Unlock()
for {
// limit blocking here for short intervals so that scheduling
// may proceed even if there have been no recent pod changes
p := q.podUpdates.Await(enqueuePopTimeout)
if p == nil {
signalled := runtime.After(q.deltaCond.Wait)
// we've yielded the lock
select {
case <-time.After(enqueueWaitTimeout):
q.deltaCond.Broadcast() // abort Wait()
<-signalled // wait for lock re-acquisition
log.V(4).Infoln("timed out waiting for a pod update")
case <-signalled:
// we've acquired the lock and there may be
// changes for us to process now
}
continue
}
pod := p.(*Pod)
if recoverAssignedSlave(pod.Pod) != "" {
log.V(3).Infof("dequeuing assigned pod for scheduling: %v", pod.Pod.Name)
q.dequeue(pod.GetUID())
} else if pod.InGracefulTermination() {
// pods which are pre-scheduled (i.e. NodeName is set) may be gracefully deleted,
// even though they are not running yet.
log.V(3).Infof("dequeuing graceful deleted pre-scheduled pod for scheduling: %v", pod.Pod.Name)
q.dequeue(pod.GetUID())
} else {
// use ReplaceExisting because we are always pushing the latest state
now := time.Now()
pod.deadline = &now
if q.podQueue.Offer(pod, queue.ReplaceExisting) {
q.unscheduledCond.Broadcast()
log.V(3).Infof("queued pod for scheduling: %v", pod.Pod.Name)
} else {
log.Warningf("failed to queue pod for scheduling: %v", pod.Pod.Name)
}
}
}
}, 1*time.Second, done)
}
// implementation of scheduling plugin's NextPod func; see k8s plugin/pkg/scheduler
func (q *queuer) yield() *api.Pod {
log.V(2).Info("attempting to yield a pod")
q.lock.Lock()
defer q.lock.Unlock()
for {
// limit blocking here to short intervals so that we don't block the
// enqueuer Run() routine for very long
kpod := q.podQueue.Await(yieldPopTimeout)
if kpod == nil {
signalled := runtime.After(q.unscheduledCond.Wait)
// lock is yielded at this point and we're going to wait for either
// a timeout, or a signal that there's data
select {
case <-time.After(yieldWaitTimeout):
q.unscheduledCond.Broadcast() // abort Wait()
<-signalled // wait for the go-routine, and the lock
log.V(4).Infoln("timed out waiting for a pod to yield")
case <-signalled:
// we have acquired the lock, and there
// may be a pod for us to pop now
}
continue
}
pod := kpod.(*Pod).Pod
if podName, err := cache.MetaNamespaceKeyFunc(pod); err != nil {
log.Warningf("yield unable to understand pod object %+v, will skip: %v", pod, err)
} else if !q.podUpdates.Poll(podName, queue.POP_EVENT) {
log.V(1).Infof("yield popped a transitioning pod, skipping: %+v", pod)
} else if recoverAssignedSlave(pod) != "" {
// should never happen if enqueuePods is filtering properly
log.Warningf("yield popped an already-scheduled pod, skipping: %+v", pod)
} else {
return pod
}
}
}
type errorHandler struct {
api schedulerInterface
backoff *backoff.Backoff
qr *queuer
}
// implementation of scheduling plugin's Error func; see plugin/pkg/scheduler
func (k *errorHandler) handleSchedulingError(pod *api.Pod, schedulingErr error) {
if schedulingErr == noSuchPodErr {
log.V(2).Infof("Not rescheduling non-existent pod %v", pod.Name)
return
}
log.Infof("Error scheduling %v: %v; retrying", pod.Name, schedulingErr)
defer util.HandleCrash()
// default upstream scheduler passes pod.Name as binding.PodID
ctx := api.WithNamespace(api.NewDefaultContext(), pod.Namespace)
podKey, err := podtask.MakePodKey(ctx, pod.Name)
if err != nil {
log.Errorf("Failed to construct pod key, aborting scheduling for pod %v: %v", pod.Name, err)
return
}
k.backoff.GC()
k.api.Lock()
defer k.api.Unlock()
switch task, state := k.api.tasks().ForPod(podKey); state {
case podtask.StateUnknown:
// if we don't have a mapping here any more then someone deleted the pod
log.V(2).Infof("Could not resolve pod to task, aborting pod reschdule: %s", podKey)
return
case podtask.StatePending:
if task.Has(podtask.Launched) {
log.V(2).Infof("Skipping re-scheduling for already-launched pod %v", podKey)
return
}
breakoutEarly := queue.BreakChan(nil)
if schedulingErr == noSuitableOffersErr {
log.V(3).Infof("adding backoff breakout handler for pod %v", podKey)
breakoutEarly = queue.BreakChan(k.api.offers().Listen(podKey, func(offer *mesos.Offer) bool {
k.api.Lock()
defer k.api.Unlock()
switch task, state := k.api.tasks().Get(task.ID); state {
case podtask.StatePending:
return !task.Has(podtask.Launched) && k.api.algorithm().FitPredicate()(task, offer)
default:
// no point in continuing to check for matching offers
return true
}
}))
}
delay := k.backoff.Get(podKey)
log.V(3).Infof("requeuing pod %v with delay %v", podKey, delay)
k.qr.requeue(&Pod{Pod: pod, delay: &delay, notify: breakoutEarly})
default:
log.V(2).Infof("Task is no longer pending, aborting reschedule for pod %v", podKey)
}
}
type deleter struct {
api schedulerInterface
qr *queuer
}
// currently monitors for "pod deleted" events, upon which handle()
// is invoked.
func (k *deleter) Run(updates <-chan queue.Entry, done <-chan struct{}) {
go runtime.Until(func() {
for {
entry := <-updates
pod := entry.Value().(*Pod)
if entry.Is(queue.DELETE_EVENT) {
if err := k.deleteOne(pod); err != nil {
log.Error(err)
}
} else if !entry.Is(queue.POP_EVENT) {
k.qr.updatesAvailable()
}
}
}, 1*time.Second, done)
}
func (k *deleter) deleteOne(pod *Pod) error {
ctx := api.WithNamespace(api.NewDefaultContext(), pod.Namespace)
podKey, err := podtask.MakePodKey(ctx, pod.Name)
if err != nil {
return err
}
log.V(2).Infof("pod deleted: %v", podKey)
// order is important here: we want to make sure we have the lock before
// removing the pod from the scheduling queue. this makes the concurrent
// execution of scheduler-error-handling and delete-handling easier to
// reason about.
k.api.Lock()
defer k.api.Unlock()
// prevent the scheduler from attempting to pop this; it's also possible that
// it's concurrently being scheduled (somewhere between pod scheduling and
// binding) - if so, then we'll end up removing it from taskRegistry which
// will abort Bind()ing
k.qr.dequeue(pod.GetUID())
switch task, state := k.api.tasks().ForPod(podKey); state {
case podtask.StateUnknown:
log.V(2).Infof("Could not resolve pod '%s' to task id", podKey)
return noSuchPodErr
// determine if the task has already been launched to mesos, if not then
// cleanup is easier (unregister) since there's no state to sync
case podtask.StatePending:
if !task.Has(podtask.Launched) {
// we've been invoked in between Schedule() and Bind()
if task.HasAcceptedOffer() {
task.Offer.Release()
task.Reset()
task.Set(podtask.Deleted)
//TODO(jdef) probably want better handling here
if err := k.api.tasks().Update(task); err != nil {
return err
}
}
k.api.tasks().Unregister(task)
return nil
}
fallthrough
case podtask.StateRunning:
// signal to watchers that the related pod is going down
task.Set(podtask.Deleted)
if err := k.api.tasks().Update(task); err != nil {
log.Errorf("failed to update task w/ Deleted status: %v", err)
}
return k.api.killTask(task.ID)
default:
log.Infof("cannot kill pod '%s': non-terminal task not found %v", podKey, task.ID)
return noSuchTaskErr
}
}
// Create creates a scheduler plugin and all supporting background functions.
func (k *KubernetesScheduler) NewDefaultPluginConfig(terminate <-chan struct{}, mux *http.ServeMux) *PluginConfig {
// use ListWatch watching pods using the client by default
return k.NewPluginConfig(terminate, mux, createAllPodsLW(k.client))
}
func (k *KubernetesScheduler) NewPluginConfig(terminate <-chan struct{}, mux *http.ServeMux,
podsWatcher *cache.ListWatch) *PluginConfig {
// Watch and queue pods that need scheduling.
updates := make(chan queue.Entry, k.schedcfg.UpdatesBacklog)
podUpdates := &podStoreAdapter{queue.NewHistorical(updates)}
reflector := cache.NewReflector(podsWatcher, &api.Pod{}, podUpdates, 0)
// lock that guards critial sections that involve transferring pods from
// the store (cache) to the scheduling queue; its purpose is to maintain
// an ordering (vs interleaving) of operations that's easier to reason about.
kapi := &k8smScheduler{internal: k}
q := newQueuer(podUpdates)
podDeleter := &deleter{
api: kapi,
qr: q,
}
eh := &errorHandler{
api: kapi,
backoff: backoff.New(k.schedcfg.InitialPodBackoff.Duration, k.schedcfg.MaxPodBackoff.Duration),
qr: q,
}
startLatch := make(chan struct{})
eventBroadcaster := record.NewBroadcaster()
runtime.On(startLatch, func() {
eventBroadcaster.StartRecordingToSink(k.client.Events(""))
reflector.Run() // TODO(jdef) should listen for termination
podDeleter.Run(updates, terminate)
q.Run(terminate)
q.installDebugHandlers(mux)
podtask.InstallDebugHandlers(k.taskRegistry, mux)
})
return &PluginConfig{
Config: &plugin.Config{
NodeLister: nil,
Algorithm: &kubeScheduler{
api: kapi,
podUpdates: podUpdates,
},
Binder: &binder{api: kapi},
NextPod: q.yield,
Error: eh.handleSchedulingError,
Recorder: eventBroadcaster.NewRecorder(api.EventSource{Component: "scheduler"}),
},
api: kapi,
client: k.client,
qr: q,
deleter: podDeleter,
starting: startLatch,
}
}
type PluginConfig struct {
*plugin.Config
api schedulerInterface
client *client.Client
qr *queuer
deleter *deleter
starting chan struct{} // startup latch
}
func NewPlugin(c *PluginConfig) PluginInterface {
return &schedulingPlugin{
config: c.Config,
api: c.api,
client: c.client,
qr: c.qr,
deleter: c.deleter,
starting: c.starting,
}
}
type schedulingPlugin struct {
config *plugin.Config
api schedulerInterface
client *client.Client
qr *queuer
deleter *deleter
starting chan struct{}
}
func (s *schedulingPlugin) Run(done <-chan struct{}) {
defer close(s.starting)
go runtime.Until(s.scheduleOne, pluginRecoveryDelay, done)
}
// hacked from GoogleCloudPlatform/kubernetes/plugin/pkg/scheduler/scheduler.go,
// with the Modeler stuff removed since we don't use it because we have mesos.
func (s *schedulingPlugin) scheduleOne() {
pod := s.config.NextPod()
log.V(3).Infof("Attempting to schedule: %+v", pod)
dest, err := s.config.Algorithm.Schedule(pod, s.config.NodeLister) // call kubeScheduler.Schedule
if err != nil {
log.V(1).Infof("Failed to schedule: %+v", pod)
s.config.Recorder.Eventf(pod, "FailedScheduling", "Error scheduling: %v", err)
s.config.Error(pod, err)
return
}
b := &api.Binding{
ObjectMeta: api.ObjectMeta{Namespace: pod.Namespace, Name: pod.Name},
Target: api.ObjectReference{
Kind: "Node",
Name: dest,
},
}
if err := s.config.Binder.Bind(b); err != nil {
log.V(1).Infof("Failed to bind pod: %+v", err)
s.config.Recorder.Eventf(pod, "FailedScheduling", "Binding rejected: %v", err)
s.config.Error(pod, err)
return
}
s.config.Recorder.Eventf(pod, "Scheduled", "Successfully assigned %v to %v", pod.Name, dest)
}
// this pod may be out of sync with respect to the API server registry:
// this pod | apiserver registry
// -------------|----------------------
// host=.* | 404 ; pod was deleted
// host=.* | 5xx ; failed to sync, try again later?
// host="" | host="" ; perhaps no updates to process?
// host="" | host="..." ; pod has been scheduled and assigned, is there a task assigned? (check TaskIdKey in binding?)
// host="..." | host="" ; pod is no longer scheduled, does it need to be re-queued?
// host="..." | host="..." ; perhaps no updates to process?
//
// TODO(jdef) this needs an integration test
func (s *schedulingPlugin) reconcileTask(t *podtask.T) {
log.V(1).Infof("reconcile pod %v, assigned to slave %q", t.Pod.Name, t.Spec.AssignedSlave)
ctx := api.WithNamespace(api.NewDefaultContext(), t.Pod.Namespace)
pod, err := s.client.Pods(api.NamespaceValue(ctx)).Get(t.Pod.Name)
if err != nil {
if errors.IsNotFound(err) {
// attempt to delete
if err = s.deleter.deleteOne(&Pod{Pod: &t.Pod}); err != nil && err != noSuchPodErr && err != noSuchTaskErr {
log.Errorf("failed to delete pod: %v: %v", t.Pod.Name, err)
}
} else {
//TODO(jdef) other errors should probably trigger a retry (w/ backoff).
//For now, drop the pod on the floor
log.Warning("aborting reconciliation for pod %v: %v", t.Pod.Name, err)
}
return
}
log.Infof("pod %v scheduled on %q according to apiserver", pod.Name, pod.Spec.NodeName)
if t.Spec.AssignedSlave != pod.Spec.NodeName {
if pod.Spec.NodeName == "" {
// pod is unscheduled.
// it's possible that we dropped the pod in the scheduler error handler
// because of task misalignment with the pod (task.Has(podtask.Launched) == true)
podKey, err := podtask.MakePodKey(ctx, pod.Name)
if err != nil {
log.Error(err)
return
}
s.api.Lock()
defer s.api.Unlock()
if _, state := s.api.tasks().ForPod(podKey); state != podtask.StateUnknown {
//TODO(jdef) reconcile the task
log.Errorf("task already registered for pod %v", pod.Name)
return
}
now := time.Now()
log.V(3).Infof("reoffering pod %v", podKey)
s.qr.reoffer(&Pod{
Pod: pod,
deadline: &now,
})
} else {
// pod is scheduled.
// not sure how this happened behind our backs. attempt to reconstruct
// at least a partial podtask.T record.
//TODO(jdef) reconcile the task
log.Errorf("pod already scheduled: %v", pod.Name)
}
} else {
//TODO(jdef) for now, ignore the fact that the rest of the spec may be different
//and assume that our knowledge of the pod aligns with that of the apiserver
log.Error("pod reconciliation does not support updates; not yet implemented")
}
}
func parseSelectorOrDie(s string) fields.Selector {
selector, err := fields.ParseSelector(s)
if err != nil {
panic(err)
}
return selector
}
// createAllPodsLW returns a listWatch that finds all pods
func createAllPodsLW(cl *client.Client) *cache.ListWatch {
return cache.NewListWatchFromClient(cl, "pods", api.NamespaceAll, parseSelectorOrDie(""))
}
// Consumes *api.Pod, produces *Pod; the k8s reflector wants to push *api.Pod
// objects at us, but we want to store more flexible (Pod) type defined in
// this package. The adapter implementation facilitates this. It's a little
// hackish since the object type going in is different than the object type
// coming out -- you've been warned.
type podStoreAdapter struct {
queue.FIFO
}
func (psa *podStoreAdapter) Add(obj interface{}) error {
pod := obj.(*api.Pod)
return psa.FIFO.Add(&Pod{Pod: pod})
}
func (psa *podStoreAdapter) Update(obj interface{}) error {
pod := obj.(*api.Pod)
return psa.FIFO.Update(&Pod{Pod: pod})
}
func (psa *podStoreAdapter) Delete(obj interface{}) error {
pod := obj.(*api.Pod)
return psa.FIFO.Delete(&Pod{Pod: pod})
}
func (psa *podStoreAdapter) Get(obj interface{}) (interface{}, bool, error) {
pod := obj.(*api.Pod)
return psa.FIFO.Get(&Pod{Pod: pod})
}
// Replace will delete the contents of the store, using instead the
// given map. This store implementation does NOT take ownership of the map.
func (psa *podStoreAdapter) Replace(objs []interface{}, resourceVersion string) error {
newobjs := make([]interface{}, len(objs))
for i, v := range objs {
pod := v.(*api.Pod)
newobjs[i] = &Pod{Pod: pod}
}
return psa.FIFO.Replace(newobjs, resourceVersion)
}