forked from k3s-io/kubernetes
-
Notifications
You must be signed in to change notification settings - Fork 0
/
container_manager_linux.go
552 lines (487 loc) · 15.6 KB
/
container_manager_linux.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
// +build linux
/*
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 cm
import (
"fmt"
"os"
"os/exec"
"path"
"strconv"
"strings"
"sync"
"time"
"github.com/golang/glog"
"github.com/opencontainers/runc/libcontainer/cgroups"
"github.com/opencontainers/runc/libcontainer/cgroups/fs"
"github.com/opencontainers/runc/libcontainer/configs"
"k8s.io/kubernetes/pkg/api"
"k8s.io/kubernetes/pkg/api/resource"
"k8s.io/kubernetes/pkg/kubelet/cadvisor"
"k8s.io/kubernetes/pkg/util"
utilerrors "k8s.io/kubernetes/pkg/util/errors"
"k8s.io/kubernetes/pkg/util/mount"
"k8s.io/kubernetes/pkg/util/oom"
"k8s.io/kubernetes/pkg/util/sets"
utilsysctl "k8s.io/kubernetes/pkg/util/sysctl"
"k8s.io/kubernetes/pkg/util/wait"
)
const (
// The percent of the machine memory capacity. The value is used to calculate
// docker memory resource container's hardlimit to workaround docker memory
// leakage issue. Please see kubernetes/issues/9881 for more detail.
DockerMemoryLimitThresholdPercent = 70
// The minimum memory limit allocated to docker container: 150Mi
MinDockerMemoryLimit = 150 * 1024 * 1024
)
// A non-user container tracked by the Kubelet.
type systemContainer struct {
// Absolute name of the container.
name string
// CPU limit in millicores.
cpuMillicores int64
// Function that ensures the state of the container.
// m is the cgroup manager for the specified container.
ensureStateFunc func(m *fs.Manager) error
// Manager for the cgroups of the external container.
manager *fs.Manager
}
func newSystemCgroups(containerName string) *systemContainer {
return &systemContainer{
name: containerName,
manager: createManager(containerName),
}
}
type containerManagerImpl struct {
sync.RWMutex
cadvisorInterface cadvisor.Interface
mountUtil mount.Interface
NodeConfig
status Status
// External containers being managed.
systemContainers []*systemContainer
periodicTasks []func()
}
type features struct {
cpuHardcapping bool
}
var _ ContainerManager = &containerManagerImpl{}
// checks if the required cgroups subsystems are mounted.
// As of now, only 'cpu' and 'memory' are required.
// cpu quota is a soft requirement.
func validateSystemRequirements(mountUtil mount.Interface) (features, error) {
const (
cgroupMountType = "cgroup"
localErr = "system validation failed"
)
var (
cpuMountPoint string
f features
)
mountPoints, err := mountUtil.List()
if err != nil {
return f, fmt.Errorf("%s - %v", localErr, err)
}
expectedCgroups := sets.NewString("cpu", "cpuacct", "cpuset", "memory")
for _, mountPoint := range mountPoints {
if mountPoint.Type == cgroupMountType {
for _, opt := range mountPoint.Opts {
if expectedCgroups.Has(opt) {
expectedCgroups.Delete(opt)
}
if opt == "cpu" {
cpuMountPoint = mountPoint.Path
}
}
}
}
if expectedCgroups.Len() > 0 {
return f, fmt.Errorf("%s - Following Cgroup subsystem not mounted: %v", localErr, expectedCgroups.List())
}
// Check if cpu quota is available.
// CPU cgroup is required and so it expected to be mounted at this point.
periodExists, err := util.FileExists(path.Join(cpuMountPoint, "cpu.cfs_period_us"))
if err != nil {
glog.Errorf("failed to detect if CPU cgroup cpu.cfs_period_us is available - %v", err)
}
quotaExists, err := util.FileExists(path.Join(cpuMountPoint, "cpu.cfs_quota_us"))
if err != nil {
glog.Errorf("failed to detect if CPU cgroup cpu.cfs_quota_us is available - %v", err)
}
if quotaExists && periodExists {
f.cpuHardcapping = true
}
return f, nil
}
// TODO(vmarmol): Add limits to the system containers.
// Takes the absolute name of the specified containers.
// Empty container name disables use of the specified container.
func NewContainerManager(mountUtil mount.Interface, cadvisorInterface cadvisor.Interface, nodeConfig NodeConfig) (ContainerManager, error) {
return &containerManagerImpl{
cadvisorInterface: cadvisorInterface,
mountUtil: mountUtil,
NodeConfig: nodeConfig,
}, nil
}
// Create a cgroup container manager.
func createManager(containerName string) *fs.Manager {
return &fs.Manager{
Cgroups: &configs.Cgroup{
Parent: "/",
Name: containerName,
Resources: &configs.Resources{
AllowAllDevices: true,
},
},
}
}
// TODO: plumb this up as a flag to Kubelet in a future PR
type KernelTunableBehavior string
const (
KernelTunableWarn KernelTunableBehavior = "warn"
KernelTunableError KernelTunableBehavior = "error"
KernelTunableModify KernelTunableBehavior = "modify"
)
// setupKernelTunables validates kernel tunable flags are set as expected
// depending upon the specified option, it will either warn, error, or modify the kernel tunable flags
func setupKernelTunables(option KernelTunableBehavior) error {
desiredState := map[string]int{
utilsysctl.VmOvercommitMemory: utilsysctl.VmOvercommitMemoryAlways,
utilsysctl.VmPanicOnOOM: utilsysctl.VmPanicOnOOMInvokeOOMKiller,
utilsysctl.KernelPanic: utilsysctl.KernelPanicRebootTimeout,
utilsysctl.KernelPanicOnOops: utilsysctl.KernelPanicOnOopsAlways,
}
errList := []error{}
for flag, expectedValue := range desiredState {
val, err := utilsysctl.GetSysctl(flag)
if err != nil {
errList = append(errList, err)
continue
}
if val == expectedValue {
continue
}
switch option {
case KernelTunableError:
errList = append(errList, fmt.Errorf("Invalid kernel flag: %v, expected value: %v, actual value: %v", flag, expectedValue, val))
case KernelTunableWarn:
glog.V(2).Infof("Invalid kernel flag: %v, expected value: %v, actual value: %v", flag, expectedValue, val)
case KernelTunableModify:
glog.V(2).Infof("Updating kernel flag: %v, expected value: %v, actual value: %v", flag, expectedValue, val)
err = utilsysctl.SetSysctl(flag, expectedValue)
if err != nil {
errList = append(errList, err)
}
}
}
return utilerrors.NewAggregate(errList)
}
func (cm *containerManagerImpl) setupNode() error {
f, err := validateSystemRequirements(cm.mountUtil)
if err != nil {
return err
}
if !f.cpuHardcapping {
cm.status.SoftRequirements = fmt.Errorf("CPU hardcapping unsupported")
}
// TODO: plumb kernel tunable options into container manager, right now, we modify by default
if err := setupKernelTunables(KernelTunableModify); err != nil {
return err
}
systemContainers := []*systemContainer{}
if cm.ContainerRuntime == "docker" {
if cm.RuntimeCgroupsName != "" {
cont := newSystemCgroups(cm.RuntimeCgroupsName)
info, err := cm.cadvisorInterface.MachineInfo()
var capacity = api.ResourceList{}
if err != nil {
} else {
capacity = cadvisor.CapacityFromMachineInfo(info)
}
memoryLimit := (int64(capacity.Memory().Value() * DockerMemoryLimitThresholdPercent / 100))
if memoryLimit < MinDockerMemoryLimit {
glog.Warningf("Memory limit %d for container %s is too small, reset it to %d", memoryLimit, cm.RuntimeCgroupsName, MinDockerMemoryLimit)
memoryLimit = MinDockerMemoryLimit
}
glog.V(2).Infof("Configure resource-only container %s with memory limit: %d", cm.RuntimeCgroupsName, memoryLimit)
dockerContainer := &fs.Manager{
Cgroups: &configs.Cgroup{
Parent: "/",
Name: cm.RuntimeCgroupsName,
Resources: &configs.Resources{
Memory: memoryLimit,
MemorySwap: -1,
AllowAllDevices: true,
},
},
}
cont.ensureStateFunc = func(manager *fs.Manager) error {
return ensureDockerInContainer(cm.cadvisorInterface, -900, dockerContainer)
}
systemContainers = append(systemContainers, cont)
} else {
cm.periodicTasks = append(cm.periodicTasks, func() {
cont, err := getContainerNameForProcess("docker")
if err != nil {
glog.Error(err)
return
}
cm.Lock()
defer cm.Unlock()
cm.RuntimeCgroupsName = cont
})
}
}
if cm.SystemCgroupsName != "" {
if cm.SystemCgroupsName == "/" {
return fmt.Errorf("system container cannot be root (\"/\")")
}
cont := newSystemCgroups(cm.SystemCgroupsName)
rootContainer := &fs.Manager{
Cgroups: &configs.Cgroup{
Parent: "/",
Name: "/",
},
}
cont.ensureStateFunc = func(manager *fs.Manager) error {
return ensureSystemCgroups(rootContainer, manager)
}
systemContainers = append(systemContainers, cont)
}
if cm.KubeletCgroupsName != "" {
cont := newSystemCgroups(cm.KubeletCgroupsName)
manager := fs.Manager{
Cgroups: &configs.Cgroup{
Parent: "/",
Name: cm.KubeletCgroupsName,
Resources: &configs.Resources{
AllowAllDevices: true,
},
},
}
cont.ensureStateFunc = func(_ *fs.Manager) error {
return manager.Apply(os.Getpid())
}
systemContainers = append(systemContainers, cont)
} else {
cm.periodicTasks = append(cm.periodicTasks, func() {
cont, err := getContainer(os.Getpid())
if err != nil {
glog.Error("failed to find cgroups of kubelet - %v", err)
return
}
cm.Lock()
defer cm.Unlock()
cm.KubeletCgroupsName = cont
})
}
cm.systemContainers = systemContainers
return nil
}
func getContainerNameForProcess(name string) (string, error) {
pids, err := getPidsForProcess(name)
if err != nil {
return "", fmt.Errorf("failed to detect process id for %q - %v", name, err)
}
if len(pids) == 0 {
return "", nil
}
cont, err := getContainer(pids[0])
if err != nil {
return "", err
}
return cont, nil
}
func (cm *containerManagerImpl) GetNodeConfig() NodeConfig {
cm.RLock()
defer cm.RUnlock()
return cm.NodeConfig
}
func (cm *containerManagerImpl) Status() Status {
cm.RLock()
defer cm.RUnlock()
return cm.status
}
func (cm *containerManagerImpl) Start() error {
// Setup the node
if err := cm.setupNode(); err != nil {
return err
}
// Don't run a background thread if there are no ensureStateFuncs.
numEnsureStateFuncs := 0
for _, cont := range cm.systemContainers {
if cont.ensureStateFunc != nil {
numEnsureStateFuncs++
}
}
if numEnsureStateFuncs >= 0 {
go wait.Until(func() {
for _, cont := range cm.systemContainers {
if cont.ensureStateFunc != nil {
if err := cont.ensureStateFunc(cont.manager); err != nil {
glog.Warningf("[ContainerManager] Failed to ensure state of %q: %v", cont.name, err)
}
}
}
}, time.Minute, wait.NeverStop)
}
// Run ensure state functions every minute.
if len(cm.periodicTasks) > 0 {
go wait.Until(func() {
for _, task := range cm.periodicTasks {
if task != nil {
task()
}
}
}, 5*time.Minute, wait.NeverStop)
}
return nil
}
func (cm *containerManagerImpl) SystemCgroupsLimit() api.ResourceList {
cpuLimit := int64(0)
// Sum up resources of all external containers.
for _, cont := range cm.systemContainers {
cpuLimit += cont.cpuMillicores
}
return api.ResourceList{
api.ResourceCPU: *resource.NewMilliQuantity(
cpuLimit,
resource.DecimalSI),
}
}
func isProcessRunningInHost(pid int) (bool, error) {
// Get init mount namespace. Mount namespace is unique for all containers.
initMntNs, err := os.Readlink("/proc/1/ns/mnt")
if err != nil {
return false, fmt.Errorf("failed to find mount namespace of init process")
}
processMntNs, err := os.Readlink(fmt.Sprintf("/proc/%d/ns/mnt", pid))
if err != nil {
return false, fmt.Errorf("failed to find mount namespace of process %q", pid)
}
return initMntNs == processMntNs, nil
}
func getPidsForProcess(name string) ([]int, error) {
out, err := exec.Command("pidof", name).Output()
if err != nil {
return []int{}, fmt.Errorf("failed to find pid of %q: %v", name, err)
}
// The output of pidof is a list of pids.
pids := []int{}
for _, pidStr := range strings.Split(strings.TrimSpace(string(out)), " ") {
pid, err := strconv.Atoi(pidStr)
if err != nil {
continue
}
pids = append(pids, pid)
}
return pids, nil
}
// Ensures that the Docker daemon is in the desired container.
func ensureDockerInContainer(cadvisor cadvisor.Interface, oomScoreAdj int, manager *fs.Manager) error {
pids, err := getPidsForProcess("docker")
if err != nil {
return err
}
// Move if the pid is not already in the desired container.
errs := []error{}
for _, pid := range pids {
if runningInHost, err := isProcessRunningInHost(pid); err != nil {
errs = append(errs, err)
// Err on the side of caution. Avoid moving the docker daemon unless we are able to identify its context.
continue
} else if !runningInHost {
// Docker daemon is running inside a container. Don't touch that.
continue
}
cont, err := getContainer(pid)
if err != nil {
errs = append(errs, fmt.Errorf("failed to find container of PID %d: %v", pid, err))
}
if cont != manager.Cgroups.Name {
err = manager.Apply(pid)
if err != nil {
errs = append(errs, fmt.Errorf("failed to move PID %d (in %q) to %q", pid, cont, manager.Cgroups.Name))
}
}
// Also apply oom-score-adj to processes
oomAdjuster := oom.NewOOMAdjuster()
if err := oomAdjuster.ApplyOOMScoreAdj(pid, oomScoreAdj); err != nil {
errs = append(errs, fmt.Errorf("failed to apply oom score %d to PID %d", oomScoreAdj, pid))
}
}
return utilerrors.NewAggregate(errs)
}
// Gets the (CPU) container the specified pid is in.
func getContainer(pid int) (string, error) {
cgs, err := cgroups.ParseCgroupFile(fmt.Sprintf("/proc/%d/cgroup", pid))
if err != nil {
return "", err
}
cg, ok := cgs["cpu"]
if ok {
return cg, nil
}
return "", cgroups.NewNotFoundError("cpu")
}
// Ensures the system container is created and all non-kernel threads and process 1
// without a container are moved to it.
//
// The reason of leaving kernel threads at root cgroup is that we don't want to tie the
// execution of these threads with to-be defined /system quota and create priority inversions.
//
func ensureSystemCgroups(rootContainer *fs.Manager, manager *fs.Manager) error {
// Move non-kernel PIDs to the system container.
attemptsRemaining := 10
var errs []error
for attemptsRemaining >= 0 {
// Only keep errors on latest attempt.
errs = []error{}
attemptsRemaining--
allPids, err := rootContainer.GetPids()
if err != nil {
errs = append(errs, fmt.Errorf("failed to list PIDs for root: %v", err))
continue
}
// Remove kernel pids and other protected PIDs (pid 1, PIDs already in system & kubelet containers)
pids := make([]int, 0, len(allPids))
for _, pid := range allPids {
if pid == 1 || isKernelPid(pid) {
continue
}
pids = append(pids, pid)
}
glog.Infof("Found %d PIDs in root, %d of them are not to be moved", len(allPids), len(allPids)-len(pids))
// Check if we have moved all the non-kernel PIDs.
if len(pids) == 0 {
break
}
glog.Infof("Moving non-kernel processes: %v", pids)
for _, pid := range pids {
err := manager.Apply(pid)
if err != nil {
errs = append(errs, fmt.Errorf("failed to move PID %d into the system container %q: %v", pid, manager.Cgroups.Name, err))
}
}
}
if attemptsRemaining < 0 {
errs = append(errs, fmt.Errorf("ran out of attempts to create system containers %q", manager.Cgroups.Name))
}
return utilerrors.NewAggregate(errs)
}
// Determines whether the specified PID is a kernel PID.
func isKernelPid(pid int) bool {
// Kernel threads have no associated executable.
_, err := os.Readlink(fmt.Sprintf("/proc/%d/exe", pid))
return err != nil
}