Merge pull request #8200 from caesarxuchao/liveness-example

update example/liveness to v1beta3

examples/examples_test.go

@@ -170,6 +170,10 @@ func TestExampleObjectSchemas(t *testing.T) {
 			"glusterfs-pod":       &api.Pod{},
 			"glusterfs-endpoints": &api.Endpoints{},
 		},
+		"../examples/liveness": {
+			"exec-liveness": &api.Pod{},
+			"http-liveness": &api.Pod{},
+		},
 		"../examples": {
 			"pod":         &api.Pod{},
 			"replication": &api.ReplicationController{},

examples/liveness/README.md

@@ -0,0 +1,76 @@
+## Overview
+This example shows two types of pod health checks: HTTP checks and container execution checks.
+
+The [exec-liveness.yaml](./exec-liveness.yaml) demonstrates the container execution check.
+```
+    livenessProbe:
+      exec:
+        command:
+        - cat
+        - /tmp/health
+      initialDelaySeconds: 15
+      timeoutSeconds: 1
+```
+Kubelet executes the command cat /tmp/health in the container and reports failure if the command returns a non-zero exit code.
+
+Note that the container removes the /tmp/health file after 10 seconds,
+```
+echo ok > /tmp/health; sleep 10; rm -rf /tmp/health; sleep 600
+```
+so when Kubelet executes the health check 15 seconds (defined by initialDelaySeconds) after the container started, the check would fail.
+
+
+The [http-liveness.yaml](./http-liveness.yaml) demonstrates the HTTP check.
+```
+    livenessProbe:
+      httpGet:
+        path: /healthz
+        port: 8080
+      initialDelaySeconds: 15
+      timeoutSeconds: 1
+```
+The Kubelet sends a HTTP request to the specified path and port to perform the health check. If you take a look at image/server.go, you will see the server starts to respond with an error code 500 after 10 seconds, so the check fails.
+
+This [guide](https://github.com/GoogleCloudPlatform/kubernetes/blob/master/examples/walkthrough/k8s201.md#health-checking) has more information on health checks.
+
+## Get your hands dirty
+To show the health check is actually working, first create the pods:
+```
+# cluster/kubectl.sh create -f exec-liveness.yaml
+# cluster/kbuectl.sh create -f http-liveness.yaml
+```
+
+Check the status of the pods once they are created:
+```
+# cluster/kubectl.sh get pods
+POD             IP           CONTAINER(S)   IMAGE(S)                            HOST                                     LABELS          STATUS    CREATED     MESSAGE
+liveness-exec   10.244.3.7                                                      kubernetes-minion-f08h/130.211.122.180   test=liveness   Running   3 seconds   
+                             liveness       gcr.io/google_containers/busybox                                                             Running   2 seconds   
+liveness-http   10.244.0.8                                                      kubernetes-minion-0bks/104.197.10.10     test=liveness   Running   3 seconds   
+                             liveness       gcr.io/google_containers/liveness                                                            Running   2 seconds   
+```
+
+Check the status half a minute later, you will see the termination messages:
+```
+# cluster/kubectl.sh get pods
+POD             IP           CONTAINER(S)   IMAGE(S)                            HOST                                     LABELS          STATUS    CREATED      MESSAGE
+liveness-exec   10.244.3.7                                                      kubernetes-minion-f08h/130.211.122.180   test=liveness   Running   34 seconds   
+                             liveness       gcr.io/google_containers/busybox                                                             Running   3 seconds    last termination: exit code 137
+liveness-http   10.244.0.8                                                      kubernetes-minion-0bks/104.197.10.10     test=liveness   Running   34 seconds   
+                             liveness       gcr.io/google_containers/liveness                                                            Running   13 seconds   last termination: exit code 2
+```
+The termination messages indicate that the liveness probes have failed, and the containers have been killed and recreated.
+
+You can also see the container restart count being incremented by running `kubectl describe`.
+```
+# cluster/kubectl.sh describe pods liveness-exec | grep "Restart Count"
+Restart Count:      8
+```
+
+You would also see the killing and creating events at the bottom of the *kubectl describe* output:
+```
+  Thu, 14 May 2015 15:23:25 -0700       Thu, 14 May 2015 15:23:25 -0700 1       {kubelet kubernetes-minion-0uzf}        spec.containers{liveness}               killing      Killing 88c8b717d8b0940d52743c086b43c3fad0d725a36300b9b5f0ad3a1c8cef2d3e
+  Thu, 14 May 2015 15:23:25 -0700       Thu, 14 May 2015 15:23:25 -0700 1       {kubelet kubernetes-minion-0uzf}        spec.containers{liveness}               created      Created with docker id b254a9810073f9ee9075bb38ac29a4b063647176ad9eabd9184078ca98a60062
+  Thu, 14 May 2015 15:23:25 -0700       Thu, 14 May 2015 15:23:25 -0700 1       {kubelet kubernetes-minion-0uzf}        spec.containers{liveness}               started      Started with docker id b254a9810073f9ee9075bb38ac29a4b063647176ad9eabd9184078ca98a60062
+  ...
+```

examples/liveness/exec-liveness.yaml

@@ -1,22 +1,21 @@
-apiVersion: v1beta1
+apiVersion: v1beta3
-desiredState:
+kind: Pod
-  manifest:
+metadata:
+  labels:
+    test: liveness
+  name: liveness-exec
+spec:
   containers:
-      - image: gcr.io/google_containers/busybox
+  - args:
-        name: liveness
+    - /bin/sh
+    - -c
+    - echo ok > /tmp/health; sleep 10; rm -rf /tmp/health; sleep 600
+    image: gcr.io/google_containers/busybox
     livenessProbe:
       exec:
         command:
-              - "cat"
+        - cat
-              - "/tmp/health"
+        - /tmp/health
       initialDelaySeconds: 15
-        command:
+      timeoutSeconds: 1
-          - "/bin/sh"
+    name: liveness
-          - "-c"
-          - "echo ok > /tmp/health; sleep 10; echo fail > /tmp/health; sleep 600"
-    id: liveness-exec
-    version: v1beta1
-id: liveness-exec
-kind: Pod
-labels:
-  test: liveness

examples/liveness/http-liveness.yaml

@@ -1,19 +1,18 @@
-apiVersion: v1beta1
+apiVersion: v1beta3
-desiredState:
-  manifest:
-    containers:
-      - image: gcr.io/google_containers/liveness
-        name: liveness
-        livenessProbe:
-          httpGet:
-            path: "/healthz"
-            port: 8080
-          initialDelaySeconds: 15
-        command:
-          - /server
-    id: liveness-http
-    version: v1beta1
-id: liveness-http
 kind: Pod
+metadata:
   labels:
     test: liveness
+  name: liveness-http
+spec:
+  containers:
+  - args:
+    - /server
+    image: gcr.io/google_containers/liveness
+    livenessProbe:
+      httpGet:
+        path: /healthz
+        port: 8080
+      initialDelaySeconds: 15
+      timeoutSeconds: 1
+    name: liveness

examples/liveness/v1beta3/exec-liveness.yaml

@@ -1,29 +0,0 @@
-apiVersion: v1beta3
-kind: ReplicationController
-metadata: 
-  labels: 
-    test: liveness
-  name: liveness-exec
-spec: 
-  replicas: 1
-  selector: 
-    test: liveness
-  template: 
-    metadata: 
-      labels: 
-        test: liveness
-    spec: 
-      containers: 
-        - command: 
-            - "/bin/sh"
-            - "-c"
-            - "echo ok > /tmp/health; sleep 10; echo fail > /tmp/health; sleep 600"
-          image: gcr.io/google_containers/busybox
-          livenessProbe: 
-            exec: 
-              command: 
-                - "cat"
-                - "/tmp/health"
-            initialDelaySeconds: 15
-          name: liveness
-

examples/liveness/v1beta3/http-liveness.yaml

@@ -1,26 +0,0 @@
-apiVersion: v1beta3
-kind: ReplicationController
-metadata: 
-  labels: 
-    test: liveness
-  name: liveness-http
-spec: 
-  replicas: 1
-  selector: 
-    test: liveness
-  template: 
-    metadata: 
-      labels: 
-        test: liveness
-    spec: 
-      containers: 
-        - command: 
-            - "/server"
-          image: gcr.io/google_containers/liveness
-          livenessProbe: 
-            httpGet: 
-              path: "/healthz"
-              port: 8080
-            initialDelaySeconds: 15
-          name: liveness
-