# 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`

type remoteVersionID string

// newWarmBackend instantiates the tier type specific WarmBackend, runs
// checkWarmBackend on it.
func newWarmBackend(ctx context.Context, tier madmin.TierConfig, probe bool) (d WarmBackend, err error) {
	switch tier.Type {
	case madmin.S3:
		d, err = newWarmBackendS3(*tier.S3, tier.Name)
	case madmin.Azure:
		d, err = newWarmBackendAzure(*tier.Azure, tier.Name)
	case madmin.GCS:

      app: {{ include "minio.name" . }}
      release: {{ .Release.Name }}
      monitoring: "true"
{{- end }}
{{- if .Values.metrics.serviceMonitor.enabled }}
---
apiVersion: monitoring.coreos.com/v1
kind: Probe
metadata:
  name: {{ template "minio.fullname" . }}-cluster
  {{- if .Values.metrics.serviceMonitor.namespace }}
  namespace: {{ .Values.metrics.serviceMonitor.namespace }}
  {{- end }}
  labels:

				// TCP starts sending keepalive probes
				_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, syscall.TCP_KEEPIDLE, 15)

				// Number of probes.
				// ~ cat /proc/sys/net/ipv4/tcp_keepalive_probes (defaults to 9, we reduce it to 5)
				_ = syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, syscall.TCP_KEEPCNT, 5)

				// Wait time after successful probe in seconds.

	"github.com/minio/minio/internal/logger"
	"github.com/minio/pkg/v3/sys"
)

func oldLinux() bool {
	currentKernel, err := kernel.CurrentVersion()
	if err != nil {
		// Could not probe the kernel version
		return false
	}

	if currentKernel == 0 {
		// We could not get any valid value return false
		return false
	}

	// legacy linux indicator for printing warnings

        }

        // Only some hosts in CI are configured with Docker. We attempt to work out the OS
        // and version, so that we know whether to expect to find Docker. We don't attempt
        // to probe for whether Docker is available, because that doesn't tell us whether
        // Docker is unavailable when it should be.
        final Path osRelease = Paths.get("/etc/os-release");

        if (Files.exists(osRelease)) {

* Kubelet now exposes a new endpoint, `/metrics/probes`, which exposes a Prometheus metric containing the liveness and/or readiness probe results for a container. ([#61369](https://github.com/kubernetes/kubernetes/pull/61369), [@rramkumar1](https://github.com/rramkumar1))

### SIG Network

  - Health check (liveness & readiness) probes using an HTTPGetAction will no longer follow redirects to different hostnames from the original probe request. Instead, these non-local redirects will be treated as a Success (the documented behavior). In this case an event with reason "ProbeWarning" will be generated, indicating that the redirect...

- Limit the body length of exec readiness/liveness probes. remote CRIs and Docker shim read a max of 16MB output of which the exec probe itself inspects 10kb. ([#82514](https://github.com/kubernetes/kubernetes/pull/82514), [@dims](https://github.com/dims))