K8S 之健康检查

健康检查

为了确保容器在部署后确实处在正常运行状态，Kubernetes提供了两种探针（Probe，支持exec、tcp和httpGet方式）来探测容器的状态：

• LivenessProbe：探测应用是否处于健康状态，如果不健康则删除重建改容器
• ReadinessProbe：探测应用是否启动完成并且处于正常服务状态，如果不正常则更新容器的状态

apiVersion: v1
kind: Pod
metadata:
  labels:
    app: nginx
  name: nginx
spec:
    containers:
    - image: nginx
      imagePullPolicy: Always
      name: http
      livenessProbe:
        httpGet:
        path: /
        port: 80
        initialDelaySeconds: 15
        timeoutSeconds: 1
      readinessProbe:
        httpGet:
        path: /ping
        port: 80
        initialDelaySeconds: 5
        timeoutSeconds: 1

Init Container

Init Container在所有容器运行之前执行（run-to-completion），常用来初始化配置。

apiVersion: v1
kind: Pod
metadata:
  name: init-demo
spec:
  containers:
  - name: nginx
    image: nginx
    ports:
    - containerPort: 80
    volumeMounts:
    - name: workdir
      mountPath: /usr/share/nginx/html
  # These containers are run during pod initialization
  initContainers:
  - name: install
    image: busybox
    command:
    - wget
    - "-O"
    - "/work-dir/index.html"
    - http://kubernetes.io
    volumeMounts:
    - name: workdir
      mountPath: "/work-dir"
  dnsPolicy: Default
  volumes:
  - name: workdir
    emptyDir: {}