forked from openshift/kubernetes
-
Notifications
You must be signed in to change notification settings - Fork 0
/
generic_scheduler.go
445 lines (400 loc) · 14.1 KB
/
generic_scheduler.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
/*
Copyright 2014 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 core
import (
"fmt"
"sort"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/golang/glog"
"k8s.io/apimachinery/pkg/util/errors"
utiltrace "k8s.io/apiserver/pkg/util/trace"
"k8s.io/client-go/util/workqueue"
"k8s.io/kubernetes/pkg/api/v1"
"k8s.io/kubernetes/plugin/pkg/scheduler/algorithm"
"k8s.io/kubernetes/plugin/pkg/scheduler/algorithm/predicates"
schedulerapi "k8s.io/kubernetes/plugin/pkg/scheduler/api"
"k8s.io/kubernetes/plugin/pkg/scheduler/schedulercache"
)
type FailedPredicateMap map[string][]algorithm.PredicateFailureReason
type FitError struct {
Pod *v1.Pod
FailedPredicates FailedPredicateMap
}
var ErrNoNodesAvailable = fmt.Errorf("no nodes available to schedule pods")
const NoNodeAvailableMsg = "No nodes are available that match all of the following predicates:"
// Error returns detailed information of why the pod failed to fit on each node
func (f *FitError) Error() string {
reasons := make(map[string]int)
for _, predicates := range f.FailedPredicates {
for _, pred := range predicates {
reasons[pred.GetReason()] += 1
}
}
sortReasonsHistogram := func() []string {
reasonStrings := []string{}
for k, v := range reasons {
reasonStrings = append(reasonStrings, fmt.Sprintf("%v (%v)", k, v))
}
sort.Strings(reasonStrings)
return reasonStrings
}
reasonMsg := fmt.Sprintf(NoNodeAvailableMsg+": %v.", strings.Join(sortReasonsHistogram(), ", "))
return reasonMsg
}
type genericScheduler struct {
cache schedulercache.Cache
equivalenceCache *EquivalenceCache
predicates map[string]algorithm.FitPredicate
priorityMetaProducer algorithm.MetadataProducer
predicateMetaProducer algorithm.MetadataProducer
prioritizers []algorithm.PriorityConfig
extenders []algorithm.SchedulerExtender
pods algorithm.PodLister
lastNodeIndexLock sync.Mutex
lastNodeIndex uint64
cachedNodeInfoMap map[string]*schedulercache.NodeInfo
}
// Schedule tries to schedule the given pod to one of node in the node list.
// If it succeeds, it will return the name of the node.
// If it fails, it will return a Fiterror error with reasons.
func (g *genericScheduler) Schedule(pod *v1.Pod, nodeLister algorithm.NodeLister) (string, error) {
trace := utiltrace.New(fmt.Sprintf("Scheduling %s/%s", pod.Namespace, pod.Name))
defer trace.LogIfLong(100 * time.Millisecond)
nodes, err := nodeLister.List()
if err != nil {
return "", err
}
if len(nodes) == 0 {
return "", ErrNoNodesAvailable
}
// Used for all fit and priority funcs.
err = g.cache.UpdateNodeNameToInfoMap(g.cachedNodeInfoMap)
if err != nil {
return "", err
}
trace.Step("Computing predicates")
filteredNodes, failedPredicateMap, err := findNodesThatFit(pod, g.cachedNodeInfoMap, nodes, g.predicates, g.extenders, g.predicateMetaProducer, g.equivalenceCache)
if err != nil {
return "", err
}
if len(filteredNodes) == 0 {
return "", &FitError{
Pod: pod,
FailedPredicates: failedPredicateMap,
}
}
trace.Step("Prioritizing")
metaPrioritiesInterface := g.priorityMetaProducer(pod, g.cachedNodeInfoMap)
priorityList, err := PrioritizeNodes(pod, g.cachedNodeInfoMap, metaPrioritiesInterface, g.prioritizers, filteredNodes, g.extenders)
if err != nil {
return "", err
}
trace.Step("Selecting host")
return g.selectHost(priorityList)
}
// Prioritizers returns a slice containing all the scheduler's priority
// functions and their config. It is exposed for testing only.
func (g *genericScheduler) Prioritizers() []algorithm.PriorityConfig {
return g.prioritizers
}
// Predicates returns a map containing all the scheduler's predicate
// functions. It is exposed for testing only.
func (g *genericScheduler) Predicates() map[string]algorithm.FitPredicate {
return g.predicates
}
// selectHost takes a prioritized list of nodes and then picks one
// in a round-robin manner from the nodes that had the highest score.
func (g *genericScheduler) selectHost(priorityList schedulerapi.HostPriorityList) (string, error) {
if len(priorityList) == 0 {
return "", fmt.Errorf("empty priorityList")
}
sort.Sort(sort.Reverse(priorityList))
maxScore := priorityList[0].Score
firstAfterMaxScore := sort.Search(len(priorityList), func(i int) bool { return priorityList[i].Score < maxScore })
g.lastNodeIndexLock.Lock()
ix := int(g.lastNodeIndex % uint64(firstAfterMaxScore))
g.lastNodeIndex++
g.lastNodeIndexLock.Unlock()
return priorityList[ix].Host, nil
}
// Filters the nodes to find the ones that fit based on the given predicate functions
// Each node is passed through the predicate functions to determine if it is a fit
func findNodesThatFit(
pod *v1.Pod,
nodeNameToInfo map[string]*schedulercache.NodeInfo,
nodes []*v1.Node,
predicateFuncs map[string]algorithm.FitPredicate,
extenders []algorithm.SchedulerExtender,
metadataProducer algorithm.MetadataProducer,
ecache *EquivalenceCache,
) ([]*v1.Node, FailedPredicateMap, error) {
var filtered []*v1.Node
failedPredicateMap := FailedPredicateMap{}
if len(predicateFuncs) == 0 {
filtered = nodes
} else {
// Create filtered list with enough space to avoid growing it
// and allow assigning.
filtered = make([]*v1.Node, len(nodes))
errs := errors.MessageCountMap{}
var predicateResultLock sync.Mutex
var filteredLen int32
// We can use the same metadata producer for all nodes.
meta := metadataProducer(pod, nodeNameToInfo)
checkNode := func(i int) {
nodeName := nodes[i].Name
fits, failedPredicates, err := podFitsOnNode(pod, meta, nodeNameToInfo[nodeName], predicateFuncs, ecache)
if err != nil {
predicateResultLock.Lock()
errs[err.Error()]++
predicateResultLock.Unlock()
return
}
if fits {
filtered[atomic.AddInt32(&filteredLen, 1)-1] = nodes[i]
} else {
predicateResultLock.Lock()
failedPredicateMap[nodeName] = failedPredicates
predicateResultLock.Unlock()
}
}
workqueue.Parallelize(16, len(nodes), checkNode)
filtered = filtered[:filteredLen]
if len(errs) > 0 {
return []*v1.Node{}, FailedPredicateMap{}, errors.CreateAggregateFromMessageCountMap(errs)
}
}
if len(filtered) > 0 && len(extenders) != 0 {
for _, extender := range extenders {
filteredList, failedMap, err := extender.Filter(pod, filtered, nodeNameToInfo)
if err != nil {
return []*v1.Node{}, FailedPredicateMap{}, err
}
for failedNodeName, failedMsg := range failedMap {
if _, found := failedPredicateMap[failedNodeName]; !found {
failedPredicateMap[failedNodeName] = []algorithm.PredicateFailureReason{}
}
failedPredicateMap[failedNodeName] = append(failedPredicateMap[failedNodeName], predicates.NewFailureReason(failedMsg))
}
filtered = filteredList
if len(filtered) == 0 {
break
}
}
}
return filtered, failedPredicateMap, nil
}
// Checks whether node with a given name and NodeInfo satisfies all predicateFuncs.
func podFitsOnNode(pod *v1.Pod, meta interface{}, info *schedulercache.NodeInfo, predicateFuncs map[string]algorithm.FitPredicate,
ecache *EquivalenceCache) (bool, []algorithm.PredicateFailureReason, error) {
var (
equivalenceHash uint64
failedPredicates []algorithm.PredicateFailureReason
eCacheAvailable bool
invalid bool
fit bool
reasons []algorithm.PredicateFailureReason
err error
)
if ecache != nil {
// getHashEquivalencePod will return immediately if no equivalence pod found
equivalenceHash = ecache.getHashEquivalencePod(pod)
eCacheAvailable = (equivalenceHash != 0)
}
for predicateKey, predicate := range predicateFuncs {
// If equivalenceCache is available
if eCacheAvailable {
// PredicateWithECache will returns it's cached predicate results
fit, reasons, invalid = ecache.PredicateWithECache(pod, info.Node().GetName(), predicateKey, equivalenceHash)
}
if !eCacheAvailable || invalid {
// we need to execute predicate functions since equivalence cache does not work
fit, reasons, err = predicate(pod, meta, info)
if err != nil {
return false, []algorithm.PredicateFailureReason{}, err
}
if eCacheAvailable {
// update equivalence cache with newly computed fit & reasons
// TODO(resouer) should we do this in another thread? any race?
ecache.UpdateCachedPredicateItem(pod, info.Node().GetName(), predicateKey, fit, reasons, equivalenceHash)
}
}
if !fit {
// eCache is available and valid, and predicates result is unfit, record the fail reasons
failedPredicates = append(failedPredicates, reasons...)
}
}
return len(failedPredicates) == 0, failedPredicates, nil
}
// Prioritizes the nodes by running the individual priority functions in parallel.
// Each priority function is expected to set a score of 0-10
// 0 is the lowest priority score (least preferred node) and 10 is the highest
// Each priority function can also have its own weight
// The node scores returned by the priority function are multiplied by the weights to get weighted scores
// All scores are finally combined (added) to get the total weighted scores of all nodes
func PrioritizeNodes(
pod *v1.Pod,
nodeNameToInfo map[string]*schedulercache.NodeInfo,
meta interface{},
priorityConfigs []algorithm.PriorityConfig,
nodes []*v1.Node,
extenders []algorithm.SchedulerExtender,
) (schedulerapi.HostPriorityList, error) {
// If no priority configs are provided, then the EqualPriority function is applied
// This is required to generate the priority list in the required format
if len(priorityConfigs) == 0 && len(extenders) == 0 {
result := make(schedulerapi.HostPriorityList, 0, len(nodes))
for i := range nodes {
hostPriority, err := EqualPriorityMap(pod, meta, nodeNameToInfo[nodes[i].Name])
if err != nil {
return nil, err
}
result = append(result, hostPriority)
}
return result, nil
}
var (
mu = sync.Mutex{}
wg = sync.WaitGroup{}
errs []error
)
appendError := func(err error) {
mu.Lock()
defer mu.Unlock()
errs = append(errs, err)
}
results := make([]schedulerapi.HostPriorityList, 0, len(priorityConfigs))
for range priorityConfigs {
results = append(results, nil)
}
for i, priorityConfig := range priorityConfigs {
if priorityConfig.Function != nil {
// DEPRECATED
wg.Add(1)
go func(index int, config algorithm.PriorityConfig) {
defer wg.Done()
var err error
results[index], err = config.Function(pod, nodeNameToInfo, nodes)
if err != nil {
appendError(err)
}
}(i, priorityConfig)
} else {
results[i] = make(schedulerapi.HostPriorityList, len(nodes))
}
}
processNode := func(index int) {
nodeInfo := nodeNameToInfo[nodes[index].Name]
var err error
for i := range priorityConfigs {
if priorityConfigs[i].Function != nil {
continue
}
results[i][index], err = priorityConfigs[i].Map(pod, meta, nodeInfo)
if err != nil {
appendError(err)
return
}
}
}
workqueue.Parallelize(16, len(nodes), processNode)
for i, priorityConfig := range priorityConfigs {
if priorityConfig.Reduce == nil {
continue
}
wg.Add(1)
go func(index int, config algorithm.PriorityConfig) {
defer wg.Done()
if err := config.Reduce(pod, meta, nodeNameToInfo, results[index]); err != nil {
appendError(err)
}
}(i, priorityConfig)
}
// Wait for all computations to be finished.
wg.Wait()
if len(errs) != 0 {
return schedulerapi.HostPriorityList{}, errors.NewAggregate(errs)
}
// Summarize all scores.
result := make(schedulerapi.HostPriorityList, 0, len(nodes))
for i := range nodes {
result = append(result, schedulerapi.HostPriority{Host: nodes[i].Name, Score: 0})
for j := range priorityConfigs {
result[i].Score += results[j][i].Score * priorityConfigs[j].Weight
}
}
if len(extenders) != 0 && nodes != nil {
combinedScores := make(map[string]int, len(nodeNameToInfo))
for _, extender := range extenders {
wg.Add(1)
go func(ext algorithm.SchedulerExtender) {
defer wg.Done()
prioritizedList, weight, err := ext.Prioritize(pod, nodes)
if err != nil {
// Prioritization errors from extender can be ignored, let k8s/other extenders determine the priorities
return
}
mu.Lock()
for i := range *prioritizedList {
host, score := (*prioritizedList)[i].Host, (*prioritizedList)[i].Score
combinedScores[host] += score * weight
}
mu.Unlock()
}(extender)
}
// wait for all go routines to finish
wg.Wait()
for i := range result {
result[i].Score += combinedScores[result[i].Host]
}
}
if glog.V(10) {
for i := range result {
glog.V(10).Infof("Host %s => Score %d", result[i].Host, result[i].Score)
}
}
return result, nil
}
// EqualPriority is a prioritizer function that gives an equal weight of one to all nodes
func EqualPriorityMap(_ *v1.Pod, _ interface{}, nodeInfo *schedulercache.NodeInfo) (schedulerapi.HostPriority, error) {
node := nodeInfo.Node()
if node == nil {
return schedulerapi.HostPriority{}, fmt.Errorf("node not found")
}
return schedulerapi.HostPriority{
Host: node.Name,
Score: 1,
}, nil
}
func NewGenericScheduler(
cache schedulercache.Cache,
eCache *EquivalenceCache,
predicates map[string]algorithm.FitPredicate,
predicateMetaProducer algorithm.MetadataProducer,
prioritizers []algorithm.PriorityConfig,
priorityMetaProducer algorithm.MetadataProducer,
extenders []algorithm.SchedulerExtender) algorithm.ScheduleAlgorithm {
return &genericScheduler{
cache: cache,
equivalenceCache: eCache,
predicates: predicates,
predicateMetaProducer: predicateMetaProducer,
prioritizers: prioritizers,
priorityMetaProducer: priorityMetaProducer,
extenders: extenders,
cachedNodeInfoMap: make(map[string]*schedulercache.NodeInfo),
}
}