K8S初始化容器init container

一、特征

优先级最高，先于其他容器启动，主要做一些初始化配置，如下载配置文件、注册信息、证书等

二、示例

在初始化容器中把init container test写入到/work_dir/index.html下，并把/work_dir挂载到/usr/share/nginx/html，

那么当访问Nginx首页时显示的内容为init container test

三、yaml文件

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: init-demo
  name: init-demo
spec:
  replicas: 1
  selector:
    matchLabels:
      app: init-demo
  template:
    metadata:
      labels:
        app: init-demo
    spec:
      initContainers:
      - name: init-container
        image: busybox
        imagePullPolicy: IfNotPresent
        command: ["sh"]
        args:
          [
            "-c",
            "echo 'init container test' >/work_dir/index.html",
          ]
        volumeMounts:
        - name: workdir
          mountPath: "/work_dir"
      containers:
      - image: nginx
        imagePullPolicy: IfNotPresent
        name: web
        ports:
        - containerPort: 80
        volumeMounts:
        - name: workdir
          mountPath: /usr/share/nginx/html
      volumes:
      - name: workdir
        emptyDir: {
    
    }