# MinIO Healthcheck

MinIO server exposes three un-authenticated, healthcheck endpoints liveness probe and a cluster probe at `/minio/health/live` and `/minio/health/cluster` respectively.

## Liveness probe

This probe always responds with '200 OK'. Only fails if 'etcd' is configured and unreachable. When liveness probe fails, Kubernetes like platforms restart the container.

```
livenessProbe:
  httpGet:
    path: /minio/health/live
    port: 9000

## Healthcheck Probe

MinIO server has two healthcheck related un-authenticated endpoints, a liveness probe to indicate if server is responding, cluster probe to check if server can be taken down for maintenance.

- Liveness probe available at `/minio/health/live`
- Cluster probe available at `/minio/health/cluster`

	healthCheckClusterPath     = "/cluster"
	healthCheckClusterReadPath = "/cluster/read"
	healthCheckPathPrefix      = minioReservedBucketPath + healthCheckPath
)

// registerHealthCheckRouter - add handler functions for liveness and readiness routes.
func registerHealthCheckRouter(router *mux.Router) {
	// Healthcheck router
	healthRouter := router.PathPrefix(healthCheckPathPrefix).Subrouter()

	// Cluster check handler to verify cluster is active

## Monitoring MinIO in Kubernetes

MinIO server exposes un-authenticated liveness endpoints so Kubernetes can natively identify unhealthy MinIO containers. MinIO also exposes Prometheus compatible data on a different endpoint to enable Prometheus users to natively monitor their MinIO deployments.

## Explore Further

	op = strings.Replace(op, "ClusterCheckHandler", "health.Cluster", 1)
	op = strings.Replace(op, "ClusterReadCheckHandler", "health.ClusterRead", 1)
	op = strings.Replace(op, "LivenessCheckHandler", "health.Liveness", 1)
	op = strings.Replace(op, "ReadinessCheckHandler", "health.Readiness", 1)
	op = strings.Replace(op, "-fm", "", 1)
	return op
}

// If trace is enabled, execute the request if it is traced by other handlers

			}
			return
		}
	}
	writeResponse(w, http.StatusOK, nil, mimeNone)
}

// LivenessCheckHandler checks whether MinIO is up. It differs from the
// readiness handler since a failing liveness check causes pod restarts
// in K8S environments. Therefore, it does not contact external systems.
func LivenessCheckHandler(w http.ResponseWriter, r *http.Request) {
	if objLayer := newObjectLayerFn(); objLayer == nil {

- Adds `\livez` for liveness health checking for kube-apiserver. Using the parameter `--maximum-startup-sequence-duration` will allow the liveness endpoint to defer boot-sequence failures for the specified duration period. ([#81969](https://github.com/kubernetes/kubernetes/pull/81969), [@logicalhan](https://github.com/logicalhan))

    * Bump metadata agent version to 0.2-0.0.21-1.
    * Expand the metadata agent's access to all API groups.
    * Remove metadata agent config maps in favor of command line flags.
    * Update the metadata agent's liveness probe to a new /healthz handler.
    * Logging Agent Improvements
    * Bump logging agent version to 0.2-1.5.33-1-k8s-1.
    * Appropriately set log severity for k8s_container.

  * Liveness and readiness probes now support more configuration parameters:
periodSeconds, successThreshold, failureThreshold
  * The new ReplicaSet API (Beta) in the Extensions API group is similar to

- kubelet
  - The deprecated `--experimental-fail-swap-on` flag has been removed ([#69552](https://github.com/kubernetes/kubernetes/pull/69552), [@Pingan2017](https://github.com/Pingan2017))