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server: readyz & defrag triggers grpc health server flips to NOT_SERVING
Signed-off-by: Chao Chen <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,155 @@ | ||
| // Copyright 2023 The etcd 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 v3rpc | ||
|
|
||
| import ( | ||
| "context" | ||
| "fmt" | ||
| "sync" | ||
| "time" | ||
|
|
||
| "go.uber.org/zap" | ||
| "google.golang.org/grpc/health" | ||
| healthpb "google.golang.org/grpc/health/grpc_health_v1" | ||
|
|
||
| "go.etcd.io/raft/v3" | ||
|
|
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| "go.etcd.io/etcd/api/v3/etcdserverpb" | ||
| "go.etcd.io/etcd/client/pkg/v3/types" | ||
| "go.etcd.io/etcd/server/v3/auth" | ||
| "go.etcd.io/etcd/server/v3/etcdserver" | ||
| ) | ||
|
|
||
| type healthNotifier interface { | ||
| StartServe() | ||
| StopServe(reason string) | ||
| } | ||
|
|
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| type healthChecker struct { | ||
| hs *health.Server | ||
|
|
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| mu sync.RWMutex | ||
| served bool | ||
|
|
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| // implements readyz prober | ||
| s *etcdserver.EtcdServer | ||
| // prober configuration TODO 2023-09-13 externalize as etcd server flag | ||
| successThreshold int | ||
| failureThreshold int | ||
| healthCheckInterval time.Duration | ||
| // prober state | ||
| successCount int | ||
| failureCount int | ||
| } | ||
|
|
||
| func NewHealthChecker(hs *health.Server, s *etcdserver.EtcdServer) healthNotifier { | ||
| hc := &healthChecker{hs: hs, s: s, successThreshold: 2, failureThreshold: 3, healthCheckInterval: 100 * time.Millisecond} | ||
| // set grpc health server as serving status blindly since | ||
| // the grpc server will serve iff s.ReadyNotify() is closed. | ||
| hc.StartServe() | ||
|
|
||
| go hc.startProbe() | ||
| return hc | ||
| } | ||
|
|
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| func (hc *healthChecker) StartServe() { | ||
| if hc.hs != nil { | ||
| if hc.s.Logger() != nil { | ||
| hc.s.Logger().Info("start serving gRPC requests from client") | ||
| } | ||
| hc.hs.SetServingStatus("", healthpb.HealthCheckResponse_SERVING) | ||
| hc.changeServedTo(true) | ||
| } | ||
| } | ||
|
|
||
| func (hc *healthChecker) StopServe(reason string) { | ||
| if hc.hs != nil { | ||
| if hc.s.Logger() != nil { | ||
| hc.s.Logger().Warn("stop serving gRPC requests from client", zap.String("reason", reason)) | ||
| } | ||
| hc.hs.SetServingStatus("", healthpb.HealthCheckResponse_NOT_SERVING) | ||
| hc.changeServedTo(false) | ||
| } | ||
| } | ||
|
|
||
| func (hc *healthChecker) changeServedTo(served bool) { | ||
| hc.mu.Lock() | ||
| defer hc.mu.Unlock() | ||
| hc.served = served | ||
| } | ||
|
|
||
| func (hc *healthChecker) IsServed() bool { | ||
| hc.mu.RLock() | ||
| defer hc.mu.RUnlock() | ||
| return hc.served | ||
| } | ||
|
|
||
| func (hc *healthChecker) startProbe() { | ||
| // stop probing if there is no consumer. | ||
| if hc.hs == nil { | ||
| return | ||
| } | ||
|
|
||
| ticker := time.NewTicker(hc.healthCheckInterval) | ||
| defer ticker.Stop() | ||
| for { | ||
| select { | ||
| case <-hc.s.StoppingNotify(): | ||
| return | ||
| case <-ticker.C: | ||
| if ready, notReadyReason := checkReadyz(hc.s, 2*time.Second); ready { | ||
| hc.successCount += 1 | ||
| hc.failureCount = 0 | ||
| if hc.successCount >= hc.successThreshold && !hc.IsServed() { | ||
| hc.StartServe() | ||
| } | ||
| } else { | ||
| hc.failureCount += 1 | ||
| hc.successCount = 0 | ||
| hc.s.Logger().Warn("readyz check failed", zap.Int("failure-count", hc.failureCount)) | ||
| if hc.failureCount >= hc.failureThreshold && hc.IsServed() { | ||
| hc.StopServe(notReadyReason) | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
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||
| // checkReadyz prober implementation should be in sync with readyz design in the future. | ||
| // https://docs.google.com/document/d/1109lUxD326yRwmMVX-tkJMpm8pTbOw7MD1XsSIo37MU | ||
| // it is now in sync with etcdhttp.HandleHealth implementation | ||
| // 1. checkLeader | ||
| // 2. checkAlarms | ||
| // 3. checkQuorumRead | ||
| func checkReadyz(s *etcdserver.EtcdServer, timeout time.Duration) (ready bool, notReadyReason string) { | ||
| if s.Leader() == types.ID(raft.None) { | ||
| return false, "local member does not have leader" | ||
| } | ||
| for _, alarm := range s.Alarms() { | ||
| if types.ID(alarm.MemberID) == s.MemberId() && alarm.Alarm == etcdserverpb.AlarmType_CORRUPT { | ||
| return false, "local member has corrupt alarm" | ||
| } | ||
| } | ||
| ctx, cancel := context.WithTimeout(context.Background(), timeout) | ||
| // range requests will only be timed-out in the LinearizableReadNotify phase, and | ||
| // blocking in the mvcc phase in case of defrag. | ||
| // However, use solely LinearizableReadNotify to indicate readyz will produce false positive serving status when defrag is active. | ||
| _, err := s.Range(ctx, &etcdserverpb.RangeRequest{KeysOnly: true, Limit: 1}) | ||
| cancel() | ||
| if err != nil && err != auth.ErrUserEmpty && err != auth.ErrPermissionDenied { | ||
| return false, fmt.Sprintf("local member quorum read with %s timeout failed due to %v", timeout.String(), err) | ||
| } | ||
| return true, "" | ||
| } |
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