4ce334aa49
With go RWMutex design, no goroutine should expect to be able to acquire a read lock until the read lock has been released, if one goroutine call lock. The original design is to reload cni network config on every single Status CRI gRPC call. If one RunPodSandbox request holds read lock to allocate IP for too long, all other RunPodSandbox/StopPodSandbox requests will wait for the RunPodSandbox request to release read lock. And the Status CRI call will fail and kubelet becomes NOTReady. Reload cni network config at every single Status CRI call is not necessary and also brings NOTReady situation. To lower the possibility of NOTReady, CRI will reload cni network config if there is any valid fs change events from the cni network config dir. Signed-off-by: Wei Fu <fuweid89@gmail.com>
122 lines
3.3 KiB
Go
122 lines
3.3 KiB
Go
/*
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Copyright The Containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package server
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import (
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"os"
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"sync"
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cni "github.com/containerd/go-cni"
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"github.com/fsnotify/fsnotify"
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"github.com/pkg/errors"
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"github.com/sirupsen/logrus"
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)
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// cniNetConfSyncer is used to reload cni network conf triggered by fs change
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// events.
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type cniNetConfSyncer struct {
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// only used for lastSyncStatus
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sync.RWMutex
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lastSyncStatus error
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watcher *fsnotify.Watcher
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confDir string
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netPlugin cni.CNI
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loadOpts []cni.CNIOpt
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}
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// newCNINetConfSyncer creates cni network conf syncer.
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func newCNINetConfSyncer(confDir string, netPlugin cni.CNI, loadOpts []cni.CNIOpt) (*cniNetConfSyncer, error) {
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watcher, err := fsnotify.NewWatcher()
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if err != nil {
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return nil, errors.Wrap(err, "failed to create fsnotify watcher")
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}
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if err := os.MkdirAll(confDir, 0700); err != nil {
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return nil, errors.Wrapf(err, "failed to create cni conf dir=%s for watch", confDir)
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}
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if err := watcher.Add(confDir); err != nil {
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return nil, errors.Wrapf(err, "failed to watch cni conf dir %s", confDir)
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}
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syncer := &cniNetConfSyncer{
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watcher: watcher,
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confDir: confDir,
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netPlugin: netPlugin,
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loadOpts: loadOpts,
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}
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if err := syncer.netPlugin.Load(syncer.loadOpts...); err != nil {
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logrus.WithError(err).Error("failed to load cni during init, please check CRI plugin status before setting up network for pods")
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syncer.updateLastStatus(err)
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}
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return syncer, nil
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}
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// syncLoop monitors any fs change events from cni conf dir and tries to reload
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// cni configuration.
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func (syncer *cniNetConfSyncer) syncLoop() error {
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for {
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select {
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case event := <-syncer.watcher.Events:
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// Only reload config when receiving write/rename/remove
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// events
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//
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// TODO(fuweid): Might only reload target cni config
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// files to prevent no-ops.
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if event.Op&(fsnotify.Chmod|fsnotify.Create) > 0 {
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logrus.Debugf("ignore event from cni conf dir: %s", event)
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continue
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}
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logrus.Debugf("receiving change event from cni conf dir: %s", event)
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lerr := syncer.netPlugin.Load(syncer.loadOpts...)
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if lerr != nil {
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logrus.WithError(lerr).
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Errorf("failed to reload cni configuration after receiving fs change event(%s)", event)
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}
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syncer.updateLastStatus(lerr)
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case err := <-syncer.watcher.Errors:
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if err != nil {
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logrus.WithError(err).Error("failed to continue sync cni conf change")
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return err
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}
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}
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}
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}
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// lastStatus retrieves last sync status.
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func (syncer *cniNetConfSyncer) lastStatus() error {
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syncer.RLock()
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defer syncer.RUnlock()
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return syncer.lastSyncStatus
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}
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// updateLastStatus will be called after every single cni load.
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func (syncer *cniNetConfSyncer) updateLastStatus(err error) {
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syncer.Lock()
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defer syncer.Unlock()
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syncer.lastSyncStatus = err
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}
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// stop stops watcher in the syncLoop.
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func (syncer *cniNetConfSyncer) stop() error {
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return syncer.watcher.Close()
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}
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