创建一个job

job是k8s的名字空间级别的资源，通过创建pod来管理container，一般用来执行批处理任务

template.spec.restartPolicy代表job的重启策略，这里是从不重启，即job启动的pod失败之后也不会重新启动

apiVersion: batch/v1
kind: Job
metadata:
  name: pi
  namespace: stream
  labels:
    app: pi
spec:
  template:
    metadata:
      name: pi
    spec:
      containers:
      - name: pi
        image: hello-world
        imagePullPolicy: IfNotPresent
        command: ["echo", "Hello world!"]
      restartPolicy: Never