K8S initialization container init container

1. Features

The highest priority, starting before other containers, mainly to do some initial configuration, such as downloading configuration files, registration information, certificates, etc.

Two, example

In the initialization container, write init container test to /work_dir/index.html, and mount /work_dir to /usr/share/nginx/html,

Then when you visit the Nginx homepage, the content displayed is init container test

Three, yaml file

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: {
    
    }