pod replicaset deployment

pod:

缺点：不支持高并发，不支持自动恢复

apiVersion: v1
kind: Pod
metadata:
  name: demo
spec:
  containers:
  - image: httpd
    name: httpd
    imagePullPolicy: Always

replicaset:是pod的封装，有自愈的功能

缺点：不支持滚动更新，无法更改template

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: demo-rc
  labels:
    app: demo-rc
spec:
  replicas: 2
  selector:
    matchLabels:
      app: demo-rc
  template:
    metadata:
      labels:
        app: demo-rc
    spec:
      containers:
      - name: httpd
        image: httpd
        imagePullPolicy: Always

deployment:

是replicaset的进一步封装，具备滚动更新的功能

apiVersion: apps/v1
kind: Deployment
metadata:
  name: httpd-deployment
  labels:
    app: httpd-deployment
spec:
  replicas: 2
  selector:
    matchLabels:
      app: httpd-demo
  template:
    metadata:
      labels:
        app: httpd-demo
    spec:
      containers:
      - name: httpd
        image: httpd
        imagePullPolicy: Always
        ports:
        - containerPort: 80
        env:
        - name: VERSION
          value: "v1"