Pod控制器应用进阶二

Kubernetes Pod控制器应用

容器监控探针类型有三种：

    ExecAction,TCPSockeAction,HTTPGetAction

    kubectl explain pods.spec.containers.livenessProbe

    kubectl explain pods.spec.containers.livenessProbe.exec
    命令执行返回成功是成功的，如果返回状态码是不成功的

    使用exec存活性探测：

[root@master test]# kubectl get pod -w
	NAME                          READY     STATUS    RESTARTS   AGE
	client                        1/1       Running   0          1d
	liveness-exec-pod             1/1       Running   5          6m
	myapp-848b5b879b-4xpl7        1/1       Running   0          1d
	myapp-848b5b879b-7gtn4        1/1       Running   0          1d
	myapp-848b5b879b-xtcdd        1/1       Running   0          1d
	nginx-deploy-5b595999-fsxlp   1/1       Running   0          1d
	^C[root@master test]# ls
	liveness-exec.yaml
	[root@master test]# cat liveness-exec.yaml 
	apiVersion: v1
	kind: Pod
	metadata:
	  name: liveness-exec-pod
	  namespace: default
	spec:
	  containers:
	  - name: liveness-exec-container
	    image: busybox:latest
	    imagePullPolicy: IfNotPresent
	    command: ["/bin/sh","-c","touch /tmp/healthy; sleep 30; rm -f /tmp/healthy; sleep 3600"]
	    livenessProbe:
	      exec:
	        command: ["test","-e","tmp/healthy"]
	      initialDelaySeconds: 1
	      periodSeconds: 3  #探测时间间隔3秒


	kubectl describe pods liveness-exec-pod 查看pod的运行日志
	Restart Count:  3  重启3次了
	Liveness:       exec [test -e tmp/healthy] delay=1s timeout=1s period=3s #success=1 #failure=3

	监控pod已经重启五次了
	[root@master test]# kubectl get pod -w
	NAME                          READY     STATUS    RESTARTS   AGE
	client                        1/1       Running   0          1d
	liveness-exec-pod             1/1       Running   5          6m
	myapp-848b5b879b-4xpl7        1/1       Running   0          1d
	myapp-848b5b879b-7gtn4        1/1       Running   0          1d
	myapp-848b5b879b-xtcdd        1/1       Running   0          1d
	nginx-deploy-5b595999-fsxlp   1/1       Running   0          1d

 

使用tcpSocket探测
    kubectl explain pods.spec.containers.livenessProbe.tcpSocket

    使用httpGet探测
    kubectl explain pods.spec.containers.livenessProbe.httpGet

使用tcpSocket探测
	kubectl explain pods.spec.containers.livenessProbe.tcpSocket

	使用httpGet探测
	kubectl explain pods.spec.containers.livenessProbe.httpGet

进入这个容器：
    kubectl exec -it liveness-httpget -- /bin/sh
    这时候我们在容器的内部删除index.html网页
    / # rm -f /usr/share/nginx/html/index.html

    过了几秒后，我们再次查看pod的信息
    kubectl describe pods liveness-httpget

    日志内容：
    Restart Count:  1
    Liveness:       http-get http://:http/index.html delay=1s timeout=1s period=3s #success=1 #failure=3

    再次回到容器中：L
    kubectl exec -it liveness-httpget -- /bin/sh
    文件出现了 /usr/share/nginx/html/index.html

    容器启动了并不一定是可以正常使用的，需要里面的服务正常启动之后才可以使用，如：redis和tomcat
    这时候我们需要做一个探测。

    这时候就用到了Pod应用状态就绪监测：
    [root@master test]# cat readiness-httpget.yaml 

apiVersion: v1
	kind: Pod
	metadata:
	  name: readiness-httpget-container
	  namespace: default
	spec:
	  containers:
	  - name: liveness-httpget-container
	    image: ikubernetes/myapp:v1
	    imagePullPolicy: IfNotPresent
	    ports:
	      - name: http
	        containerPort: 80
	    readinessProbe:
	       httpGet:
	         port: http
	         path: /index.html
	       initialDelaySeconds: 1
	       periodSeconds: 3

	启动：kubectl create -f readiness-httpget.yaml
	这时候kubectl get pods 是正常启动的
	这时候进入容器内部
	kubectl exec -it readiness-httpget -- /bin/sh
	rm -f /usr/share/nginx/html/index.html
	这时候kubectl get pods 是不启动的
    # echo "hi">usr/share/nginx/html/index.html
    kubectl get pods
    这个时候是启动成功的

启动后多久和终止前多久？
    kubectl explain pods.spec.containers.lifecycle

    利用busybox来测试：
    busybox是有httpd服务的，但是没有网页，我们做一个网页，然后再启动httpd服务，看看两个能不能关联。

    cat poststart-pod.yaml   #暂时有问题

    [root@master manifests]# cat poststart-pod.yaml 
	apiVersion: v1
	kind: Pod
	metadata:
	  name: poststart-pod
	  namespace: default
	spec:
	  containers:
	  - name: busybox-httpd
	    image: busybox:latest
	    imagePullPolicy: IfNotPresent
	    lifecycle:
	      postStart:
	        exec:
	          command: ['bin/sh','-c','echo Home_Page >> /tmp/index.html']
	    command: ["/bin/httpd"]
	    args: ["-f","-h /tmp"]