minio/cmd/healthcheck-handler.go
Nitish Tiwari 10b01ac836
Add healthcheck endpoints (#5543)
This PR adds readiness and liveness endpoints to probe Minio server
instance health. Endpoints can only be accessed without authentication
and the paths are /minio/health/live and /minio/health/ready for
liveness and readiness respectively.

The new healthcheck liveness endpoint is used for Docker healthcheck
now.

Fixes #5357
Fixes #5514
2018-03-12 11:46:53 +05:30

70 lines
2.5 KiB
Go

/*
* Minio Cloud Storage, (C) 2018 Minio, Inc.
*
* 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 cmd
import (
"fmt"
"net/http"
"runtime"
)
const (
minioHealthGoroutineThreshold = 1000
)
// ReadinessCheckHandler -- checks if there are more than threshold number of goroutines running,
// returns service unavailable.
// Readiness probes are used to detect situations where application is under heavy load
// and temporarily unable to serve. In a orchestrated setup like Kubernetes, containers reporting
// that they are not ready do not receive traffic through Kubernetes Services.
func ReadinessCheckHandler(w http.ResponseWriter, r *http.Request) {
if err := goroutineCountCheck(minioHealthGoroutineThreshold); err != nil {
writeResponse(w, http.StatusServiceUnavailable, nil, mimeNone)
return
}
writeResponse(w, http.StatusOK, nil, mimeNone)
}
// LivenessCheckHandler -- checks if server can ListBuckets internally. If not, server is
// considered to have failed and needs to be restarted.
// Liveness probes are used to detect situations where application (minio)
// has gone into a state where it can not recover except by being restarted.
func LivenessCheckHandler(w http.ResponseWriter, r *http.Request) {
objLayer := newObjectLayerFn()
// Service not initialized yet
if objLayer == nil {
writeResponse(w, http.StatusServiceUnavailable, nil, mimeNone)
return
}
// List buckets is unsuccessful, means server is having issues, send 503 service unavailable
if _, err := objLayer.ListBuckets(); err != nil {
writeResponse(w, http.StatusServiceUnavailable, nil, mimeNone)
return
}
writeResponse(w, http.StatusOK, nil, mimeNone)
}
// checks threshold against total number of go-routines in the system and throws error if
// more than threshold go-routines are running.
func goroutineCountCheck(threshold int) error {
count := runtime.NumGoroutine()
if count > threshold {
return fmt.Errorf("too many goroutines (%d > %d)", count, threshold)
}
return nil
}