Add readiness and liveness probes to API server (#365)

* Add readiness and liveness probes to API server

* Use `intstr.FromInt(8899)` instead

cli/kubernetes/provider.go

@@ -193,6 +193,8 @@ func (provider *Provider) CreateMizuApiServerPod(ctx context.Context, opts *ApiS
 		command = append(command, "--namespace", opts.Namespace)
 	}
 
+	port := intstr.FromInt(8899)
+
 	pod := &core.Pod{
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      opts.PodName,
@@ -232,6 +234,25 @@ func (provider *Provider) CreateMizuApiServerPod(ctx context.Context, opts *ApiS
 							"memory": memRequests,
 						},
 					},
+					ReadinessProbe: &core.Probe{
+						Handler: core.Handler{
+							TCPSocket: &core.TCPSocketAction{
+								Port: port,
+							},
+						},
+						InitialDelaySeconds: 5,
+						PeriodSeconds:       10,
+					},
+					LivenessProbe: &core.Probe{
+						Handler: core.Handler{
+							HTTPGet: &core.HTTPGetAction{
+								Path: "/echo",
+								Port: port,
+							},
+						},
+						InitialDelaySeconds: 5,
+						PeriodSeconds:       10,
+					},
 				},
 			},
 			Volumes: []core.Volume{