forked from msazurestackworkloads/kubernetes
-
Notifications
You must be signed in to change notification settings - Fork 0
/
controller.go
638 lines (552 loc) · 21.5 KB
/
controller.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
/*
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 resourcequota
import (
"fmt"
"sort"
"strings"
"sync"
"time"
"github.com/golang/glog"
"k8s.io/apimachinery/pkg/api/meta"
"k8s.io/apimachinery/pkg/runtime/schema"
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
"k8s.io/apimachinery/pkg/util/sets"
"k8s.io/apimachinery/pkg/util/wait"
"k8s.io/apiserver/pkg/admission"
"k8s.io/client-go/util/workqueue"
"k8s.io/kubernetes/pkg/api"
"k8s.io/kubernetes/pkg/quota"
_ "k8s.io/kubernetes/pkg/util/workqueue/prometheus" // for workqueue metric registration
resourcequotaapi "k8s.io/kubernetes/plugin/pkg/admission/resourcequota/apis/resourcequota"
)
// Evaluator is used to see if quota constraints are satisfied.
type Evaluator interface {
// Evaluate takes an operation and checks to see if quota constraints are satisfied. It returns an error if they are not.
// The default implementation process related operations in chunks when possible.
Evaluate(a admission.Attributes) error
}
type quotaEvaluator struct {
quotaAccessor QuotaAccessor
// lockAcquisitionFunc acquires any required locks and returns a cleanup method to defer
lockAcquisitionFunc func([]api.ResourceQuota) func()
// registry that knows how to measure usage for objects
registry quota.Registry
// TODO these are used together to bucket items by namespace and then batch them up for processing.
// The technique is valuable for rollup activities to avoid fanout and reduce resource contention.
// We could move this into a library if another component needed it.
// queue is indexed by namespace, so that we bundle up on a per-namespace basis
queue *workqueue.Type
workLock sync.Mutex
work map[string][]*admissionWaiter
dirtyWork map[string][]*admissionWaiter
inProgress sets.String
// controls the run method so that we can cleanly conform to the Evaluator interface
workers int
stopCh <-chan struct{}
init sync.Once
// lets us know what resources are limited by default
config *resourcequotaapi.Configuration
}
type admissionWaiter struct {
attributes admission.Attributes
finished chan struct{}
result error
}
type defaultDeny struct{}
func (defaultDeny) Error() string {
return "DEFAULT DENY"
}
// IsDefaultDeny returns true if the error is defaultDeny
func IsDefaultDeny(err error) bool {
if err == nil {
return false
}
_, ok := err.(defaultDeny)
return ok
}
func newAdmissionWaiter(a admission.Attributes) *admissionWaiter {
return &admissionWaiter{
attributes: a,
finished: make(chan struct{}),
result: defaultDeny{},
}
}
// NewQuotaEvaluator configures an admission controller that can enforce quota constraints
// using the provided registry. The registry must have the capability to handle group/kinds that
// are persisted by the server this admission controller is intercepting
func NewQuotaEvaluator(quotaAccessor QuotaAccessor, registry quota.Registry, lockAcquisitionFunc func([]api.ResourceQuota) func(), config *resourcequotaapi.Configuration, workers int, stopCh <-chan struct{}) Evaluator {
// if we get a nil config, just create an empty default.
if config == nil {
config = &resourcequotaapi.Configuration{}
}
return "aEvaluator{
quotaAccessor: quotaAccessor,
lockAcquisitionFunc: lockAcquisitionFunc,
registry: registry,
queue: workqueue.NewNamed("admission_quota_controller"),
work: map[string][]*admissionWaiter{},
dirtyWork: map[string][]*admissionWaiter{},
inProgress: sets.String{},
workers: workers,
stopCh: stopCh,
config: config,
}
}
// Run begins watching and syncing.
func (e *quotaEvaluator) run() {
defer utilruntime.HandleCrash()
for i := 0; i < e.workers; i++ {
go wait.Until(e.doWork, time.Second, e.stopCh)
}
<-e.stopCh
glog.Infof("Shutting down quota evaluator")
e.queue.ShutDown()
}
func (e *quotaEvaluator) doWork() {
workFunc := func() bool {
ns, admissionAttributes, quit := e.getWork()
if quit {
return true
}
defer e.completeWork(ns)
if len(admissionAttributes) == 0 {
return false
}
e.checkAttributes(ns, admissionAttributes)
return false
}
for {
if quit := workFunc(); quit {
glog.Infof("quota evaluator worker shutdown")
return
}
}
}
// checkAttributes iterates evaluates all the waiting admissionAttributes. It will always notify all waiters
// before returning. The default is to deny.
func (e *quotaEvaluator) checkAttributes(ns string, admissionAttributes []*admissionWaiter) {
// notify all on exit
defer func() {
for _, admissionAttribute := range admissionAttributes {
close(admissionAttribute.finished)
}
}()
quotas, err := e.quotaAccessor.GetQuotas(ns)
if err != nil {
for _, admissionAttribute := range admissionAttributes {
admissionAttribute.result = err
}
return
}
// if limited resources are disabled, we can just return safely when there are no quotas.
limitedResourcesDisabled := len(e.config.LimitedResources) == 0
if len(quotas) == 0 && limitedResourcesDisabled {
for _, admissionAttribute := range admissionAttributes {
admissionAttribute.result = nil
}
return
}
if e.lockAcquisitionFunc != nil {
releaseLocks := e.lockAcquisitionFunc(quotas)
defer releaseLocks()
}
e.checkQuotas(quotas, admissionAttributes, 3)
}
// checkQuotas checks the admission attributes against the passed quotas. If a quota applies, it will attempt to update it
// AFTER it has checked all the admissionAttributes. The method breaks down into phase like this:
// 0. make a copy of the quotas to act as a "running" quota so we know what we need to update and can still compare against the
// originals
// 1. check each admission attribute to see if it fits within *all* the quotas. If it doesn't fit, mark the waiter as failed
// and the running quota don't change. If it did fit, check to see if any quota was changed. It there was no quota change
// mark the waiter as succeeded. If some quota did change, update the running quotas
// 2. If no running quota was changed, return now since no updates are needed.
// 3. for each quota that has changed, attempt an update. If all updates succeeded, update all unset waiters to success status and return. If the some
// updates failed on conflict errors and we have retries left, re-get the failed quota from our cache for the latest version
// and recurse into this method with the subset. It's safe for us to evaluate ONLY the subset, because the other quota
// documents for these waiters have already been evaluated. Step 1, will mark all the ones that should already have succeeded.
func (e *quotaEvaluator) checkQuotas(quotas []api.ResourceQuota, admissionAttributes []*admissionWaiter, remainingRetries int) {
// yet another copy to compare against originals to see if we actually have deltas
originalQuotas, err := copyQuotas(quotas)
if err != nil {
utilruntime.HandleError(err)
return
}
atLeastOneChanged := false
for i := range admissionAttributes {
admissionAttribute := admissionAttributes[i]
newQuotas, err := e.checkRequest(quotas, admissionAttribute.attributes)
if err != nil {
admissionAttribute.result = err
continue
}
// if the new quotas are the same as the old quotas, then this particular one doesn't issue any updates
// that means that no quota docs applied, so it can get a pass
atLeastOneChangeForThisWaiter := false
for j := range newQuotas {
if !quota.Equals(quotas[j].Status.Used, newQuotas[j].Status.Used) {
atLeastOneChanged = true
atLeastOneChangeForThisWaiter = true
break
}
}
if !atLeastOneChangeForThisWaiter {
admissionAttribute.result = nil
}
quotas = newQuotas
}
// if none of the requests changed anything, there's no reason to issue an update, just fail them all now
if !atLeastOneChanged {
return
}
// now go through and try to issue updates. Things get a little weird here:
// 1. check to see if the quota changed. If not, skip.
// 2. if the quota changed and the update passes, be happy
// 3. if the quota changed and the update fails, add the original to a retry list
var updatedFailedQuotas []api.ResourceQuota
var lastErr error
for i := range quotas {
newQuota := quotas[i]
// if this quota didn't have its status changed, skip it
if quota.Equals(originalQuotas[i].Status.Used, newQuota.Status.Used) {
continue
}
if err := e.quotaAccessor.UpdateQuotaStatus(&newQuota); err != nil {
updatedFailedQuotas = append(updatedFailedQuotas, newQuota)
lastErr = err
}
}
if len(updatedFailedQuotas) == 0 {
// all the updates succeeded. At this point, anything with the default deny error was just waiting to
// get a successful update, so we can mark and notify
for _, admissionAttribute := range admissionAttributes {
if IsDefaultDeny(admissionAttribute.result) {
admissionAttribute.result = nil
}
}
return
}
// at this point, errors are fatal. Update all waiters without status to failed and return
if remainingRetries <= 0 {
for _, admissionAttribute := range admissionAttributes {
if IsDefaultDeny(admissionAttribute.result) {
admissionAttribute.result = lastErr
}
}
return
}
// this retry logic has the same bug that its possible to be checking against quota in a state that never actually exists where
// you've added a new documented, then updated an old one, your resource matches both and you're only checking one
// updates for these quota names failed. Get the current quotas in the namespace, compare by name, check to see if the
// resource versions have changed. If not, we're going to fall through an fail everything. If they all have, then we can try again
newQuotas, err := e.quotaAccessor.GetQuotas(quotas[0].Namespace)
if err != nil {
// this means that updates failed. Anything with a default deny error has failed and we need to let them know
for _, admissionAttribute := range admissionAttributes {
if IsDefaultDeny(admissionAttribute.result) {
admissionAttribute.result = lastErr
}
}
return
}
// this logic goes through our cache to find the new version of all quotas that failed update. If something has been removed
// it is skipped on this retry. After all, you removed it.
quotasToCheck := []api.ResourceQuota{}
for _, newQuota := range newQuotas {
for _, oldQuota := range updatedFailedQuotas {
if newQuota.Name == oldQuota.Name {
quotasToCheck = append(quotasToCheck, newQuota)
break
}
}
}
e.checkQuotas(quotasToCheck, admissionAttributes, remainingRetries-1)
}
func copyQuotas(in []api.ResourceQuota) ([]api.ResourceQuota, error) {
out := make([]api.ResourceQuota, 0, len(in))
for _, quota := range in {
copied, err := api.Scheme.Copy("a)
if err != nil {
return nil, err
}
out = append(out, *copied.(*api.ResourceQuota))
}
return out, nil
}
// filterLimitedResourcesByGroupResource filters the input that match the specified groupResource
func filterLimitedResourcesByGroupResource(input []resourcequotaapi.LimitedResource, groupResource schema.GroupResource) []resourcequotaapi.LimitedResource {
result := []resourcequotaapi.LimitedResource{}
for i := range input {
limitedResource := input[i]
limitedGroupResource := schema.GroupResource{Group: limitedResource.APIGroup, Resource: limitedResource.Resource}
if limitedGroupResource == groupResource {
result = append(result, limitedResource)
}
}
return result
}
// limitedByDefault determines from the specfified usage and limitedResources the set of resources names
// that must be present in a covering quota. It returns an error if it was unable to determine if
// a resource was not limited by default.
func limitedByDefault(usage api.ResourceList, limitedResources []resourcequotaapi.LimitedResource) []api.ResourceName {
result := []api.ResourceName{}
for _, limitedResource := range limitedResources {
for k, v := range usage {
// if a resource is consumed, we need to check if it matches on the limited resource list.
if v.Sign() == 1 {
// if we get a match, we add it to limited set
for _, matchContain := range limitedResource.MatchContains {
if strings.Contains(string(k), matchContain) {
result = append(result, k)
break
}
}
}
}
}
return result
}
// checkRequest verifies that the request does not exceed any quota constraint. it returns a copy of quotas not yet persisted
// that capture what the usage would be if the request succeeded. It return an error if the is insufficient quota to satisfy the request
func (e *quotaEvaluator) checkRequest(quotas []api.ResourceQuota, a admission.Attributes) ([]api.ResourceQuota, error) {
namespace := a.GetNamespace()
evaluators := e.registry.Evaluators()
evaluator, found := evaluators[a.GetKind().GroupKind()]
if !found {
return quotas, nil
}
op := a.GetOperation()
if !evaluator.Handles(op) {
return quotas, nil
}
// if we have limited resources enabled for this resource, always calculate usage
inputObject := a.GetObject()
// determine the set of resource names that must exist in a covering quota
limitedResourceNames := []api.ResourceName{}
limitedResources := filterLimitedResourcesByGroupResource(e.config.LimitedResources, a.GetResource().GroupResource())
if len(limitedResources) > 0 {
deltaUsage, err := evaluator.Usage(inputObject)
if err != nil {
return quotas, err
}
limitedResourceNames = limitedByDefault(deltaUsage, limitedResources)
}
limitedResourceNamesSet := quota.ToSet(limitedResourceNames)
// find the set of quotas that are pertinent to this request
// reject if we match the quota, but usage is not calculated yet
// reject if the input object does not satisfy quota constraints
// if there are no pertinent quotas, we can just return
interestingQuotaIndexes := []int{}
// track the cumulative set of resources that were required across all quotas
// this is needed to know if we have satisfied any constraints where consumption
// was limited by default.
restrictedResourcesSet := sets.String{}
for i := range quotas {
resourceQuota := quotas[i]
match, err := evaluator.Matches(&resourceQuota, inputObject)
if err != nil {
return quotas, err
}
if !match {
continue
}
hardResources := quota.ResourceNames(resourceQuota.Status.Hard)
restrictedResources := evaluator.MatchingResources(hardResources)
if err := evaluator.Constraints(restrictedResources, inputObject); err != nil {
return nil, admission.NewForbidden(a, fmt.Errorf("failed quota: %s: %v", resourceQuota.Name, err))
}
if !hasUsageStats(&resourceQuota) {
return nil, admission.NewForbidden(a, fmt.Errorf("status unknown for quota: %s", resourceQuota.Name))
}
interestingQuotaIndexes = append(interestingQuotaIndexes, i)
localRestrictedResourcesSet := quota.ToSet(restrictedResources)
restrictedResourcesSet.Insert(localRestrictedResourcesSet.List()...)
}
// verify that for every resource that had limited by default consumption
// enabled that there was a corresponding quota that covered its use.
// if not, we reject the request.
hasNoCoveringQuota := limitedResourceNamesSet.Difference(restrictedResourcesSet)
if len(hasNoCoveringQuota) > 0 {
return quotas, fmt.Errorf("insufficient quota to consume: %v", strings.Join(hasNoCoveringQuota.List(), ","))
}
if len(interestingQuotaIndexes) == 0 {
return quotas, nil
}
// Usage of some resources cannot be counted in isolation. For example, when
// the resource represents a number of unique references to external
// resource. In such a case an evaluator needs to process other objects in
// the same namespace which needs to be known.
if accessor, err := meta.Accessor(inputObject); namespace != "" && err == nil {
if accessor.GetNamespace() == "" {
accessor.SetNamespace(namespace)
}
}
// there is at least one quota that definitely matches our object
// as a result, we need to measure the usage of this object for quota
// on updates, we need to subtract the previous measured usage
// if usage shows no change, just return since it has no impact on quota
deltaUsage, err := evaluator.Usage(inputObject)
if err != nil {
return quotas, err
}
// ensure that usage for input object is never negative (this would mean a resource made a negative resource requirement)
if negativeUsage := quota.IsNegative(deltaUsage); len(negativeUsage) > 0 {
return nil, admission.NewForbidden(a, fmt.Errorf("quota usage is negative for resource(s): %s", prettyPrintResourceNames(negativeUsage)))
}
if admission.Update == op {
prevItem := a.GetOldObject()
if prevItem == nil {
return nil, admission.NewForbidden(a, fmt.Errorf("unable to get previous usage since prior version of object was not found"))
}
// if we can definitively determine that this is not a case of "create on update",
// then charge based on the delta. Otherwise, bill the maximum
metadata, err := meta.Accessor(prevItem)
if err == nil && len(metadata.GetResourceVersion()) > 0 {
prevUsage, innerErr := evaluator.Usage(prevItem)
if innerErr != nil {
return quotas, innerErr
}
deltaUsage = quota.Subtract(deltaUsage, prevUsage)
}
}
if quota.IsZero(deltaUsage) {
return quotas, nil
}
outQuotas, err := copyQuotas(quotas)
if err != nil {
return nil, err
}
for _, index := range interestingQuotaIndexes {
resourceQuota := outQuotas[index]
hardResources := quota.ResourceNames(resourceQuota.Status.Hard)
requestedUsage := quota.Mask(deltaUsage, hardResources)
newUsage := quota.Add(resourceQuota.Status.Used, requestedUsage)
maskedNewUsage := quota.Mask(newUsage, quota.ResourceNames(requestedUsage))
if allowed, exceeded := quota.LessThanOrEqual(maskedNewUsage, resourceQuota.Status.Hard); !allowed {
failedRequestedUsage := quota.Mask(requestedUsage, exceeded)
failedUsed := quota.Mask(resourceQuota.Status.Used, exceeded)
failedHard := quota.Mask(resourceQuota.Status.Hard, exceeded)
return nil, admission.NewForbidden(a,
fmt.Errorf("exceeded quota: %s, requested: %s, used: %s, limited: %s",
resourceQuota.Name,
prettyPrint(failedRequestedUsage),
prettyPrint(failedUsed),
prettyPrint(failedHard)))
}
// update to the new usage number
outQuotas[index].Status.Used = newUsage
}
return outQuotas, nil
}
func (e *quotaEvaluator) Evaluate(a admission.Attributes) error {
e.init.Do(func() {
go e.run()
})
// if we do not know how to evaluate use for this kind, just ignore
evaluators := e.registry.Evaluators()
evaluator, found := evaluators[a.GetKind().GroupKind()]
if !found {
return nil
}
// for this kind, check if the operation could mutate any quota resources
// if no resources tracked by quota are impacted, then just return
op := a.GetOperation()
if !evaluator.Handles(op) {
return nil
}
waiter := newAdmissionWaiter(a)
e.addWork(waiter)
// wait for completion or timeout
select {
case <-waiter.finished:
case <-time.After(10 * time.Second):
return fmt.Errorf("timeout")
}
return waiter.result
}
func (e *quotaEvaluator) addWork(a *admissionWaiter) {
e.workLock.Lock()
defer e.workLock.Unlock()
ns := a.attributes.GetNamespace()
// this Add can trigger a Get BEFORE the work is added to a list, but this is ok because the getWork routine
// waits the worklock before retrieving the work to do, so the writes in this method will be observed
e.queue.Add(ns)
if e.inProgress.Has(ns) {
e.dirtyWork[ns] = append(e.dirtyWork[ns], a)
return
}
e.work[ns] = append(e.work[ns], a)
}
func (e *quotaEvaluator) completeWork(ns string) {
e.workLock.Lock()
defer e.workLock.Unlock()
e.queue.Done(ns)
e.work[ns] = e.dirtyWork[ns]
delete(e.dirtyWork, ns)
e.inProgress.Delete(ns)
}
func (e *quotaEvaluator) getWork() (string, []*admissionWaiter, bool) {
uncastNS, shutdown := e.queue.Get()
if shutdown {
return "", []*admissionWaiter{}, shutdown
}
ns := uncastNS.(string)
e.workLock.Lock()
defer e.workLock.Unlock()
// at this point, we know we have a coherent view of e.work. It is entirely possible
// that our workqueue has another item requeued to it, but we'll pick it up early. This ok
// because the next time will go into our dirty list
work := e.work[ns]
delete(e.work, ns)
delete(e.dirtyWork, ns)
if len(work) != 0 {
e.inProgress.Insert(ns)
return ns, work, false
}
e.queue.Done(ns)
e.inProgress.Delete(ns)
return ns, []*admissionWaiter{}, false
}
// prettyPrint formats a resource list for usage in errors
// it outputs resources sorted in increasing order
func prettyPrint(item api.ResourceList) string {
parts := []string{}
keys := []string{}
for key := range item {
keys = append(keys, string(key))
}
sort.Strings(keys)
for _, key := range keys {
value := item[api.ResourceName(key)]
constraint := key + "=" + value.String()
parts = append(parts, constraint)
}
return strings.Join(parts, ",")
}
func prettyPrintResourceNames(a []api.ResourceName) string {
values := []string{}
for _, value := range a {
values = append(values, string(value))
}
sort.Strings(values)
return strings.Join(values, ",")
}
// hasUsageStats returns true if for each hard constraint there is a value for its current usage
func hasUsageStats(resourceQuota *api.ResourceQuota) bool {
for resourceName := range resourceQuota.Status.Hard {
if _, found := resourceQuota.Status.Used[resourceName]; !found {
return false
}
}
return true
}