k8s创建Job资源报错： `selector` not auto-generated

先上结论：

在Job资源的yaml文件，如果你要是用"selector.matchLabels"，那就必须同时设置“selector.manual:true”。

Job.selector.manual表示是否可以使用selector选择器选择pod，其默认值是false。
 

通过yaml文件创建Job资源，执行kubectl create命令报错：

[root@master ~]# kubectl create -f job-demo.yaml
The Job "job-demo2" is invalid: spec.selector: Invalid value: v1.LabelSelector{MatchLabels:map[string]string{"app":"busybox", "controller-uid":"b0e5ed28-fe5e-4562-b934-116a6a5a0b10"}, MatchExpressions:[]v1.LabelSelectorRequirement(nil)}: `selector` not auto-generated
[root@master ~]# 

我的job-demo.yaml文件内容如下：

[root@master ~]# cat job-demo.yaml
apiVersion: batch/v1
kind: Job
metadata:
  namespace: dev
  name: job-demo2
  labels:
    type: job
    env: pc
spec: 
  selector:
    matchLabels:
      app: busybox
  template:
     metadata:
       labels:
         app: busybox
     spec:
       restartPolicy: OnFailure
       containers:
       - image: busybox
         name: busybox-app


[root@master ~]#

报错信息中显示：'selector' not auto-generated

再次编辑此yaml文件，在'selector'上面增加一行代码：manualSelector:true

最后重新执行kubectl create -f job-demo.yaml命令就不报错了。

附Job.spec.manualSelector的文档：

[root@master ~]# kubectl explain Job.spec.manualSelector
KIND:     Job
VERSION:  batch/v1

FIELD:    manualSelector <boolean>

DESCRIPTION:
     manualSelector controls generation of pod labels and pod selectors. Leave
     `manualSelector` unset unless you are certain what you are doing. When
     false or unset, the system pick labels unique to this job and appends those
     labels to the pod template. When true, the user is responsible for picking
     unique labels and specifying the selector. Failure to pick a unique label
     may cause this and other jobs to not function correctly. However, You may
     see `manualSelector=true` in jobs that were created with the old
     `extensions/v1beta1` API. More info:
     https://kubernetes.io/docs/concepts/workloads/controllers/jobs-run-to-completion/#specifying-your-own-pod-selector
[root@master ~]#