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Kubernetes精讲之控制器的使用

article 2025/1/18 6:09:02

一什么是控制器

官方文档：

工作负载管理 | Kubernetes

控制器也是管理pod的一种手段

自主式pod：pod退出或意外关闭后不会被重新创建
控制器管理的 Pod：在控制器的生命周期里，始终要维持 Pod 的副本数目

Pod控制器是管理pod的中间层，使用Pod控制器之后，只需要告诉Pod控制器，想要多少个什么样的Pod就可以了，它会创建出满足条件的Pod并确保每一个Pod资源处于用户期望的目标状态。如果Pod资源在运行中出现故障，它会基于指定策略重新编排Pod

当建立控制器后，会把期望值写入etcd，k8s中的apiserver检索etcd中我们保存的期望状态，并对比pod的当前状态，如果出现差异代码自驱动立即恢复

二控制器常用类型

控制器名称	控制器用途
Replication Controller	比较原始的pod控制器，已经被废弃，由ReplicaSet替代
ReplicaSet	ReplicaSet 确保任何时间都有指定数量的 Pod 副本在运行
Deployment	一个 Deployment 为 Pod和 ReplicaSet提供声明式的更新能力
DaemonSet	DaemonSet 确保全指定节点上运行一个 Pod 的副本
StatefulSet	StatefulSet 是用来管理有状态应用的工作负载 API 对象。
Job	执行批处理任务，仅执行一次任务，保证任务的一个或多个Pod成功结束
CronJob	Cron Job 创建基于时间调度的 Jobs。
HPA全称Horizontal Pod Autoscaler	根据资源利用率自动调整service中Pod数量，实现Pod水平自动缩放

三 replicaset控制器

3.1 replicaset功能

ReplicaSet 是下一代的 Replication Controller，官方推荐使用ReplicaSet
ReplicaSet和Replication Controller的唯一区别是选择器的支持，ReplicaSet支持新的基于集合的选择器需求
ReplicaSet 确保任何时间都有指定数量的 Pod 副本在运行
虽然 ReplicaSets 可以独立使用，但今天它主要被Deployments 用作协调 Pod 创建、删除和更新的机制

3.2 replicaset参数说明

参数名称	字段类型	参数说明
spec	Object	详细定义对象，固定值就写Spec
spec.replicas	integer	指定维护pod数量
spec.selector	Object	Selector是对pod的标签查询，与pod数量匹配
spec.selector.matchLabels	string	指定Selector查询标签的名称和值，以key：value方式指定
spec.template	Object	指定对pod的描述信息，比如lab标签，运行容器的信息等
spec.template.metadata	Object	指定pod属性
spec.template.metadata.labels	string	指定pod标签
spec.template.spec	Object	详细定义对象
spec.template.spec.containers	list	Spec对象的容器列表定义
spec.template.spec.containers.name	string	指定容器名称
spec.template.spec.containers.image	string	指定容器镜像

3.3 replicaset 示例

[root@K8s-master ~]# kubectl create deployment haha --image myapp:v1 --dry-run=client -o yaml > haha.yml

[root@K8s-master ~]# vim haha.yml 
apiVersion: apps/v1
kind: ReplicaSet        #改为ReplicaSet
metadata:
  name: haha            #指定pod名称，一定小写，如果出现大写报错
spec:
  replicas: 2                   #指定维护pod数量为2
  selector:                             #指定检测匹配方式
    matchLabels:                #指定匹配方式为匹配标签
      app: myapp                #指定匹配的标签为app=myapp

  template:                             #模板，当副本数量不足时，会根据下面的模板创建pod副本
    metadata:
      labels:
        app: myapp
    spec:
      containers:
      - image: myapp:v1
        name: myapp
        
#replicaset是通过标签匹配pod
[root@K8s-master ~]# kubectl apply -f haha.yml 
replicaset.apps/haha created
[root@K8s-master ~]# kubectl get pods --show-labels 
NAME         READY   STATUS    RESTARTS   AGE   LABELS
haha-jb2wn   1/1     Running   0          23s   app=myapp
haha-zlfh8   1/1     Running   0          23s   app=myapp

[root@K8s-master ~]# kubectl label pod haha-jb2wn app=haha --overwrite 
pod/haha-jb2wn labeled
[root@K8s-master ~]# kubectl get pods --show-labels 
NAME         READY   STATUS    RESTARTS   AGE    LABELS
haha-6gwzg   1/1     Running   0          3s     app=myapp
haha-jb2wn   1/1     Running   0          116s   app=haha
haha-zlfh8   1/1     Running   0          116s   app=myapp


#恢复标签后
[root@K8s-master ~]# kubectl label pod haha-jb2wn app=myapp --overwrite 
pod/haha-jb2wn labeled
[root@K8s-master ~]# kubectl get pods --show-labels 
NAME         READY   STATUS    RESTARTS   AGE    LABELS
haha-6gwzg   1/1     Running   0          74s    app=myapp
haha-jb2wn   1/1     Running   0          3m7s   app=myapp


#replicaset自动控制副本数量，pod可以自愈
[root@K8s-master ~]# kubectl get pods --show-labels 
NAME         READY   STATUS    RESTARTS   AGE    LABELS
haha-6gwzg   1/1     Running   0          74s    app=myapp
haha-jb2wn   1/1     Running   0          3m7s   app=myapp
[root@K8s-master ~]# kubectl delete pods haha-jb2wn
pod "haha-jb2wn" deleted
[root@K8s-master ~]# kubectl get pods --show-labels 
NAME         READY   STATUS    RESTARTS   AGE     LABELS
haha-6gwzg   1/1     Running   0          2m21s   app=myapp
haha-vgldz   1/1     Running   0          4s      app=myapp

#回收资源
[root@K8s-master ~]# kubectl delete -f haha.yml 
replicaset.apps "haha" deleted

注意replicaset无法对版本进行维护

四 deployment 控制器

4.1 deployment控制器的功能

为了更好的解决服务编排的问题，kubernetes在V1.2版本开始，引入了Deployment控制器。
Deployment控制器并不直接管理pod，而是通过管理ReplicaSet来间接管理Pod
Deployment管理ReplicaSet，ReplicaSet管理Pod
Deployment 为 Pod 和 ReplicaSet 提供了一个申明式的定义方法
在Deployment中ReplicaSet相当于一个版本

典型的应用场景：

用来创建Pod和ReplicaSet
滚动更新和回滚
扩容和缩容
暂停与恢复

4.2 deployment控制器示例

[root@K8s-master ~]# kubectl create deployment xixi --image myapp:v1 --dry-run=client -o yaml > xixi.yml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: xixi
spec:
  replicas: 4
  selector:
    matchLabels:
      app: xixi
  template:
    metadata:
      labels:
        app: xixi
    spec:
      containers:
      - image: myapp:v1
        name: myapp

#建立pod
[root@K8s-master ~]# kubectl apply -f xixi.yml 
deployment.apps/xixi created

#查看pod信息
[root@K8s-master ~]# kubectl get pods --show-labels 
NAME                    READY   STATUS    RESTARTS   AGE   LABELS
xixi-6d65589775-h25dm   1/1     Running   0          14s   app=xixi,pod-template-hash=6d65589775
xixi-6d65589775-ss5kl   1/1     Running   0          14s   app=xixi,pod-template-hash=6d65589775
xixi-6d65589775-vxrc7   1/1     Running   0          14s   app=xixi,pod-template-hash=6d65589775
xixi-6d65589775-xs5s7   1/1     Running   0          14s   app=xixi,pod-template-hash=6d65589775

4.2.1 版本迭代

[root@K8s-master ~]# kubectl get pods -o wide
NAME                    READY   STATUS    RESTARTS   AGE   IP            NODE        NOMINATED NODE   READINESS GATES
xixi-6d65589775-h25dm   1/1     Running   0          65s   10.244.2.27   k8s-node2   <none>           <none>
xixi-6d65589775-ss5kl   1/1     Running   0          65s   10.244.1.39   k8s-node1   <none>           <none>
xixi-6d65589775-vxrc7   1/1     Running   0          65s   10.244.1.38   k8s-node1   <none>           <none>
xixi-6d65589775-xs5s7   1/1     Running   0          65s   10.244.2.28   k8s-node2   <none>           <none>

#pod运行容器版本为v1
[root@K8s-master ~]# curl 10.244.2.27
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

#
[root@K8s-master ~]# kubectl describe deployments.apps xixi 
Name:                   xixi
Namespace:              default
CreationTimestamp:      Thu, 05 Sep 2024 22:30:02 +0800
Labels:                 <none>
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=xixi
Replicas:               4 desired | 4 updated | 4 total | 4 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge   #默认每次更新25%
Pod Template:
  Labels:  app=xixi
  Containers:
   myapp:
    Image:         myapp:v1
    Port:          <none>
    Host Port:     <none>
    Environment:   <none>
    Mounts:        <none>
  Volumes:         <none>
  Node-Selectors:  <none>
  Tolerations:     <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   xixi-6d65589775 (4/4 replicas created)
Events:
  Type    Reason             Age    From                   Message
  ----    ------             ----   ----                   -------
  Normal  ScalingReplicaSet  3m37s  deployment-controller  Scaled up replica set xixi-6d65589775 to 4


#更新容器运行版本
[root@K8s-master ~]# vim xixi.yml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: xixi
spec:
  replicas: 4
  selector:
    matchLabels:
      app: xixi
  template:
    metadata:
      labels:
        app: xixi
    spec:
      containers:
      - image: myapp:v2   #更新为版本2
        name: myapp

[root@K8s-master ~]# kubectl apply -f xixi.yml 
deployment.apps/xixi configured

#测试更新效果
[root@K8s-master ~]#  kubectl get pods -o wide
NAME                    READY   STATUS    RESTARTS   AGE   IP            NODE        NOMINATED NODE   READINESS GATES
xixi-795dcd4b66-5xth9   1/1     Running   0          42s   10.244.2.30   k8s-node2   <none>           <none>
xixi-795dcd4b66-88d7v   1/1     Running   0          43s   10.244.2.29   k8s-node2   <none>           <none>
xixi-795dcd4b66-bw97v   1/1     Running   0          41s   10.244.1.41   k8s-node1   <none>           <none>
xixi-795dcd4b66-tdlps   1/1     Running   0          43s   10.244.1.40   k8s-node1   <none>           <none>
[root@K8s-master ~]# curl 10.244.2.30
Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

更新前

更新后

更新的过程是重新建立一个版本的RS，新版本的RS会把pod 重建，然后把老版本的RS回收

[root@K8s-master ~]# kubectl get all
NAME                        READY   STATUS    RESTARTS   AGE
pod/xixi-795dcd4b66-5xth9   1/1     Running   0          3m53s
pod/xixi-795dcd4b66-88d7v   1/1     Running   0          3m54s
pod/xixi-795dcd4b66-bw97v   1/1     Running   0          3m52s
pod/xixi-795dcd4b66-tdlps   1/1     Running   0          3m54s

NAME                   READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/xixi   4/4     4            4           10m

NAME                              DESIRED   CURRENT   READY   AGE
replicaset.apps/xixi-6d65589775   0         0         0       10m
replicaset.apps/xixi-795dcd4b66   4         4         4       3m54s

4.2.2 版本回滚

[root@K8s-master ~]# vim xixi.yml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: xixi
spec:
  replicas: 4
  selector:
    matchLabels:
      app: xixi
  template:
    metadata:
      labels:
        app: xixi
    spec:
      containers:
      - image: myapp:v1   #回滚到之前版本
        name: myapp

[root@K8s-master ~]# kubectl apply -f xixi.yml 
deployment.apps/xixi configured
[root@K8s-master ~]# kubectl get pods -o wide 
NAME                    READY   STATUS    RESTARTS   AGE   IP            NODE        NOMINATED NODE   READINESS GATES
xixi-6d65589775-bqm54   1/1     Running   0          17s   10.244.1.43   k8s-node1   <none>           <none>
xixi-6d65589775-f4tkv   1/1     Running   0          17s   10.244.2.32   k8s-node2   <none>           <none>
xixi-6d65589775-prf8m   1/1     Running   0          18s   10.244.1.42   k8s-node1   <none>           <none>
xixi-6d65589775-rx84x   1/1     Running   0          18s   10.244.2.31   k8s-node2   <none>           <none>
[root@K8s-master ~]# curl 10.244.1.43
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

4.2.3 滚动更新策略

[root@K8s-master ~]# vim xixi.yml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: xixi
spec:
  minReadySeconds: 5   #最小就绪时间，指定pod每隔多久更新一次
  replicas: 4
  strategy:            #指定更新策略
    rollingUpdate:
      maxSurge: 1      #比定义pod数量多几个
      maxUnavailable: 0   #比定义pod个数少几个
  selector:
    matchLabels:
      app: xixi
  template:
    metadata:
      labels:
        app: xixi
    spec:
      containers:
      - image: myapp:v2
        name: myapp


[root@K8s-master ~]# kubectl apply -f xixi.yml 

#查看效果，速度要快
[root@K8s-master ~]# kubectl get all

4.2.4 暂停及恢复

在实际生产环境中我们做的变更可能不止一处，当修改了一处后，如果执行变更就直接触发了

我们期望的触发时当我们把所有修改都搞定后一次触发

暂停，避免触发不必要的线上更新

#暂停
[root@K8s-master ~]# kubectl rollout pause deployment xixi 
deployment.apps/xixi paused

#调整副本数
[root@K8s-master ~]# vim xixi.yml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: xixi
spec:
  minReadySeconds: 5
  replicas: 6
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  selector:
    matchLabels:
      app: xixi
  template:
    metadata:
      labels:
        app: xixi
    spec:
      containers:
      - image: myapp:v2
        name: myapp
        resources:
          limits:
            cpu: 0.5
            memory: 200Mi
          requests:
            cpu: 0.5
            memory: 200Mi

#调整副本数，不受影响
[root@K8s-master ~]# kubectl describe pods xixi-795dcd4b66-
xixi-795dcd4b66-7kxtw  xixi-795dcd4b66-7slzs  xixi-795dcd4b66-l8r78  xixi-795dcd4b66-tcdvj  xixi-795dcd4b66-txclm  xixi-795dcd4b66-w9c8t


#但是更新镜像和修改资源并没有触发更新
[root@K8s-master ~]#  kubectl rollout history deployment xixi 
deployment.apps/xixi 
REVISION  CHANGE-CAUSE
5         <none>
6         <none>

#恢复后开始触发更新
[root@K8s-master ~]# kubectl rollout resume deployment xixi 
deployment.apps/xixi resumed

[root@K8s-master ~]#  kubectl rollout history deployment xixi 
deployment.apps/xixi 
REVISION  CHANGE-CAUSE
5         <none>
6         <none>
7         <none>

#查看cpu调用
[root@K8s-master ~]# kubectl describe pods xixi-784bf57f98-58rt8 
....
    Restart Count:  0
    Limits:
      cpu:     500m
      memory:  200Mi
    Requests:
      cpu:        500m
      memory:     200Mi
    Environment:  <none>
......

#回收
[root@K8s-master ~]#  kubectl delete -f xixi.yml 
deployment.apps "xixi" deleted

五 daemonset控制器

5.1 daemonset功能

DaemonSet 确保全部（或者某些）节点上运行一个 Pod 的副本。当有节点加入集群时，也会为他们新增一个 Pod ，当有节点从集群移除时，这些 Pod 也会被回收。删除 DaemonSet 将会删除它创建的所有 Pod

DaemonSet 的典型用法：

在每个节点上运行集群存储 DaemonSet，例如 glusterd、ceph。
在每个节点上运行日志收集 DaemonSet，例如 fluentd、logstash。
在每个节点上运行监控 DaemonSet，例如 Prometheus Node Exporter、zabbix agent等
一个简单的用法是在所有的节点上都启动一个 DaemonSet，将被作为每种类型的 daemon 使用
一个稍微复杂的用法是单独对每种 daemon 类型使用多个 DaemonSet，但具有不同的标志，并且对不同硬件类型具有不同的内存、CPU 要求

5.2 daemonset 示例

[root@K8s-master ~]# cp xixi.yml xixi-dm.yml
apiVersion: apps/v1
kind: DaemonSet
metadata:
  labels:
    app: xixi-dm
  name: xixi-dm
spec:
  selector:
    matchLabels:
      app: xixi-dm
  template:
    metadata:
      labels:
        app: xixi-dm
    spec:
      containers:
      - image: myapp:v1
        name: myapp

#未设置对污点的容忍
[root@K8s-master ~]# kubectl apply -f xixi-dm.yml 
daemonset.apps/xixi-dm created
[root@K8s-master ~]# kubectl get pods -o wide 
NAME            READY   STATUS    RESTARTS   AGE   IP            NODE        NOMINATED NODE   READINESS GATES
xixi-dm-pzrk9   1/1     Running   0          11s   10.244.2.43   k8s-node2   <none>           <none>
xixi-dm-whjnq   1/1     Running   0          11s   10.244.1.54   k8s-node1   <none>           <none>

#设置对污点的容忍
apiVersion: apps/v1
kind: DaemonSet
metadata:
  labels:
    app: xixi-dm
  name: xixi-dm
spec:
  selector:
    matchLabels:
      app: xixi-dm
  template:
    metadata:
      labels:
        app: xixi-dm
    spec:
      tolerations:          #对于污点节点的容忍
        - effect: NoSchedule
          operator: Exists   #对污点的容忍度，强容忍
      containers:
      - image: myapp:v1
        name: myapp
        
[root@K8s-master ~]# kubectl apply -f xixi-dm.yml 
daemonset.apps/xixi-dm configured
[root@K8s-master ~]# kubectl get pods -o wide 
NAME            READY   STATUS    RESTARTS   AGE   IP            NODE         NOMINATED NODE   READINESS GATES
xixi-dm-c6m8l   1/1     Running   0          23s   10.244.1.55   k8s-node1    <none>           <none>
xixi-dm-n6jkh   1/1     Running   0          22s   10.244.2.44   k8s-node2    <none>           <none>
xixi-dm-zz8mr   1/1     Running   0          26s   10.244.0.4    k8s-master   <none>           <none>

未设置对污点的容忍

设置对污点的容忍

[root@k8s2 pod]# cat daemonset-example.yml
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: daemonset-example
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      tolerations:      #对于污点节点的容忍
      - effect: NoSchedule
        operator: Exists   #对污点的容忍度，强容忍
      containers:
      - name: nginx
        image: nginx

[root@k8s-master ~]# kubectl get pods  -o wide
NAME              READY   STATUS    RESTARTS   AGE   IP            NODE         NOMINATED NODE   READINESS GATES
daemonset-87h6s   1/1     Running   0          47s   10.244.0.8    k8s-master   <none>           <none>
daemonset-n4vs4   1/1     Running   0          47s   10.244.2.38   k8s-node2    <none>           <none>
daemonset-vhxmq   1/1     Running   0          47s   10.244.1.40   k8s-node1    <none>           <none>


#回收
[root@k8s2 pod]# kubectl delete -f daemonset-example.yml

六 job 控制器

6.1 job控制器功能

Job，主要用于负责批量处理(一次要处理指定数量任务)短暂的一次性(每个任务仅运行一次就结束)任务

Job特点如下：

当Job创建的pod执行成功结束时，Job将记录成功结束的pod数量
当成功结束的pod达到指定的数量时，Job将完成执行

6.2 job 控制器示例：

需要一个镜像

#导入镜像
[root@K8s-master ~]# docker load  -i perl-5.34.tar.gz 
c9a63110150b: Loading layer  129.1MB/129.1MB
e019be289189: Loading layer   11.3MB/11.3MB
6e632f416458: Loading layer  19.31MB/19.31MB
327e42081bbe: Loading layer  156.5MB/156.5MB
3ffc178e6d86: Loading layer  537.7MB/537.7MB
89ab64e009d0: Loading layer  3.584kB/3.584kB
213cb8592bff: Loading layer  57.87MB/57.87MB
Loaded image: perl:5.34.0

#上传镜像
[root@K8s-master ~]# docker tag perl:5.34.0 reg.harbor.org/library/perl:5.34.0
[root@K8s-master ~]# docker push reg.harbor.org/library/perl:5.34.0 
The push refers to repository [reg.harbor.org/library/perl]
213cb8592bff: Pushed 
89ab64e009d0: Pushed 
3ffc178e6d86: Pushed 
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5.34.0: digest: sha256:7cf07e3b102361df7f0e9f8b1311baed15d4190f26b3e096f03ac87d6dab7aeb size: 1796

配置

[root@K8s-master ~]# kubectl create job haha-job --image perl:5.34.0 --dry-run=client -o yaml > haha-job.yml
[root@K8s-master ~]# vim haha-job.yml
apiVersion: batch/v1
kind: Job
metadata:
  name: haha-job
spec:
  completions: 6      #一共完成任务数为6
  parallelism: 2      #每次并行完成2个
  template:
    spec:
      containers:
      - image: perl:5.34.0
        name: perl
        command: ["perl",  "-Mbignum=bpi", "-wle", "print bpi(2000)"]  #计算Π的后2000位
      restartPolicy: Never         #关闭后不自动重启
  backoffLimit: 4                 #运行失败后尝试4重新运行

#运行
[root@K8s-master ~]# kubectl apply -f haha-job.yml 
job.batch/haha-job created
[root@K8s-master ~]# kubectl get all
NAME                 READY   STATUS              RESTARTS   AGE
pod/haha-job-6bcql   0/1     ContainerCreating   0          6s
pod/haha-job-c9zfh   0/1     ContainerCreating   0          6s

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   108m

NAME                 STATUS    COMPLETIONS   DURATION   AGE
job.batch/haha-job   Running   0/6           6s         6s

#等了一会后
[root@K8s-master ~]# kubectl get all
NAME                 READY   STATUS      RESTARTS   AGE
pod/haha-job-6bcql   0/1     Completed   0          85s
pod/haha-job-9mjl9   0/1     Completed   0          10s
pod/haha-job-c9zfh   0/1     Completed   0          85s
pod/haha-job-zsrbs   0/1     Completed   0          10s

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   109m

NAME                 STATUS    COMPLETIONS   DURATION   AGE
job.batch/haha-job   Running   2/6           85s        85s

关于重启策略设置的说明：

如果指定为OnFailure，则job会在pod出现故障时重启容器而不是创建pod，failed次数不变
如果指定为Never，则job会在pod出现故障时创建新的pod并且故障pod不会消失，也不会重启，failed次数加1
如果指定为Always的话，就意味着一直重启，意味着job任务会重复去执行了

七 cronjob 控制器

7.1 cronjob 控制器功能

Cron Job 创建基于时间调度的 Jobs。
CronJob控制器以Job控制器资源为其管控对象，并借助它管理pod资源对象，
CronJob可以以类似于Linux操作系统的周期性任务作业计划的方式控制其运行时间点及重复运行的方式。
CronJob可以在特定的时间点(反复的)去运行job任务。

7.2 cronjob 控制器示例

[root@K8s-master ~]# kubectl create cronjob haha-cjob --image busybox:latest --schedule="* * * * *" --restart Never --dry-run=client -o yaml > haha-cjob.yml
[root@K8s-master ~]# vim haha-cjob.yml
apiVersion: batch/v1
kind: CronJob
metadata:
  name: haha-cjob
spec:
  jobTemplate:
    spec:
      template:
        spec:
          containers:
          - image: busybox:latest
            name: haha-cjob
            command: ["/bin/sh","-c","date;echo Hello from the Kubernetes cluster"]
          restartPolicy: Nerver
  schedule: '* * * * *'
  
[root@K8s-master ~]# kubectl apply -f haha-cjob.yml 
cronjob.batch/haha-cjob created

[root@K8s-master ~]# kubectl get cronjobs.batch haha-cjob -o wide 
NAME        SCHEDULE    TIMEZONE   SUSPEND   ACTIVE   LAST SCHEDULE   AGE   CONTAINERS   IMAGES           SELECTOR
haha-cjob   * * * * *   <none>     False     0        <none>          45s   haha-cjob    busybox:latest   <none>

[root@K8s-master ~]# kubectl logs pods/haha-cjob-28759245-6hwvr 
Thu Sep  5 08:48:20 UTC 2024
Hello from the Kubernetes cluster

#等一分钟
[root@K8s-master ~]# kubectl logs pods/haha-cjob-2875924
pods/haha-cjob-28759245-6hwvr  pods/haha-cjob-28759246-gqnkb  
[root@K8s-master ~]# kubectl logs pods/haha-cjob-28759246-gqnkb 
Thu Sep  5 08:49:20 UTC 2024
Hello from the Kubernetes cluster

#删除
[root@K8s-master ~]# kubectl delete -f haha-cjob.yml 
cronjob.batch "haha-cjob" deleted