kubernetes 健康检查和初始化容器

Pod-hook:
postStart:
1.
$ $ vim preStart-hook.yaml
---
apiVersion: v1
kind: Pod
metadata:
  name: hook-demo1
  labels:
    app: hook
spec:
  containers:
  - name: hook-demo1
    image: nginx
    ports:
    - name: webport
      containerPort: 80
    lifecycle:
      postStart:
        exec:
          command: ["/bin/sh", "-c", "echo Hello from the postStart Hander > /usr/share/message"]

$ kubectl exec hook-demo1  -i -t  /bin/bash          
preStop:
2.强制删除
$ kubectl delete pod hook-demo1 --force --grace-period=0

$ vim preStop-hook.yaml
---
apiVersion: v1
kind: Pod
metadata:
  name: hook-demo2
  labels:
    app: hook
spec:
  containers:
  - name: hook-demo2
    image: nginx
    ports:
    - name: webport
      containerPort: 80
    volumeMounts:
    - name: message
      mountPath: /usr/share
    lifecycle:
      preStop:
        exec:
          command: ["/bin/sh", "-c", "echo Hello from the postStop Hander > /usr/share/message"]
  volumes:
  - name: message
    hostPath:
      path: /tmp

普通的pod是不能被调度到master节点上面来的

存活探针:
liveness probe
$ vim liveness-exec.yaml
---
apiVersion: v1
kind: Pode
metadata:
  name: liveness-exec
  labels:
    app: liveness
spec:
  containers:
  - name: liveness
    images: busybox
    args:
    - /bin/sh
    - -c
    - touch /tmp/healthy; sleep 30; rm -rf /tmp/healthy; sleep 600
    livenessProbe:
      exec:
        command:
        - cat
        - /tmp/healthy
      initialDelaySeconds: 5
      periodSeconds: 5

初始化容器-initcontainer
$ vim initpod1.yaml

---
apiVersion: v1
kind: Pod
metadata:
  name: init-pod
  labels:
    app: init

spec:
  initContainers:
  - name: init-myservice
    image: busybox
    command: ['sh', '-c', 'until nslookup myservice; do echo waiting for myservice; sleep 2; done;']
  - name:
    image: busybox
    command: ['sh', '-c', 'until nslookup mydb; do echo waiting for mydb; sleep 2; done;']
  containers:
  - name: main-container
    image: busybox
    command: ['sh', '-c', 'echo The app is running! && sleep 3600']