k8s (3)k8s的Pod管理

迷南。 2022-12-28 07:27 273阅读 0赞

### 文章目录 ###

*   *   *  Pod简介
         *   *  什么是Pod？
             *  Pod分类
         *  Pod特性
         *   *  Pod标签
             *  Node标签
             *  Pod的状态及生命周期
             *  Init容器
             *  配置探针
             *   *  存活探针
                 *  就绪探针

### Pod简介 ###

#### 什么是Pod？ ####

kubernetes中的一切都可以理解为是一种资源对象，pod,rs,svc,都可以理解是 一种资源对象。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzQxNDAyNQ_size_16_color_FFFFFF_t_70]

#### Pod分类 ####

Pod分为两类：

*  自主式Pod：这种Pod本身是不能自我修复的。当Pod被创建后（不论是由你直接创建还是被其它controller创建），都会被k8s调度到集群的Node上。直到pod的进程终止、被删掉。因为缺少资源而被驱逐、或者Node故障之前这个Pod都会一直保持在个Node上。Pod不会自愈。如果Pod运行的Node故障，或者是调度器本身故障，这个Pod就会被删除。同样的，如果Pod所在Node缺少资源或者Pod处于维护状态，Pod也会被驱逐。
 *  控制器管理的Pod：k8s使用更高级的称为Controller的抽象层，来管理Pod实例。Controller可以创建和管理多个Pod，提供副本管理、滚动升级和集群级别的自愈能力。例如。如果一个Node故障，Controller就能自动将该节点上的Pod调度到其他健康的Node上，虽然可以直接使用Pod，但是在K8s中通常是使用Controller来管理Pod的。

### Pod特性 ###

#### Pod标签 ####

apiVersion: apps/v1
    kind: Deployment
    metadata: 
      name: deployment-example
    spec:
      replicas: 4
      selector:
        matchLabels:
          app: nginx
      template:
        metadata:
          labels:
            app: nginx
        spec:
          containers:
          - name: nginx
            image: nginx
            imagePullPolicy: IfNotPresent

运行：

[k8s@server1 ~]$ kubectl apply -f nginx.yml 
    deployment.apps/deployment-example created
    [k8s@server1 ~]$ kubectl get pod 
    NAME                                  READY   STATUS    RESTARTS   AGE
    deployment-example-7cf7d6dbc8-dzpgg   1/1     Running   0          27s
    deployment-example-7cf7d6dbc8-r2qz8   1/1     Running   0          28s
    deployment-example-7cf7d6dbc8-sx4mv   1/1     Running   0          27s
    deployment-example-7cf7d6dbc8-v9s2d   1/1     Running   0          27s

查看pod的标签：

[k8s@server1 ~]$ kubectl get pod --show-labels 
    NAME                                  READY   STATUS    RESTARTS   AGE   LABELS
    deployment-example-7cf7d6dbc8-dzpgg   1/1     Running   0          13m   app=nginx,pod-template-hash=7cf7d6dbc8
    deployment-example-7cf7d6dbc8-r2qz8   1/1     Running   0          13m   app=nginx,pod-template-hash=7cf7d6dbc8
    deployment-example-7cf7d6dbc8-sx4mv   1/1     Running   0          13m   app=nginx,pod-template-hash=7cf7d6dbc8
    deployment-example-7cf7d6dbc8-v9s2d   1/1     Running   0          13m   app=nginx,pod-template-hash=7cf7d6dbc8

过滤标签

[k8s@server1 ~]$ kubectl get pod -l app
    NAME                                  READY   STATUS    RESTARTS   AGE
    deployment-example-7cf7d6dbc8-dzpgg   1/1     Running   0          16m
    deployment-example-7cf7d6dbc8-r2qz8   1/1     Running   0          16m
    deployment-example-7cf7d6dbc8-sx4mv   1/1     Running   0          16m
    deployment-example-7cf7d6dbc8-v9s2d   1/1     Running   0          16m
    [k8s@server1 ~]$ kubectl get pod -L app
    NAME                                  READY   STATUS    RESTARTS   AGE   APP
    deployment-example-7cf7d6dbc8-dzpgg   1/1     Running   0          17m   nginx
    deployment-example-7cf7d6dbc8-r2qz8   1/1     Running   0          17m   nginx
    deployment-example-7cf7d6dbc8-sx4mv   1/1     Running   0          17m   nginx
    deployment-example-7cf7d6dbc8-v9s2d   1/1     Running   0          17m   nginx

修改标签：

[k8s@server1 ~]$ kubectl label pod deployment-example-7cf7d6dbc8-dzpgg app=apache --overwrite 
    pod/deployment-example-7cf7d6dbc8-dzpgg labeled
    [k8s@server1 ~]$ kubectl get pod -L app
    NAME                                  READY   STATUS    RESTARTS   AGE   APP
    deployment-example-7cf7d6dbc8-b26t7   1/1     Running   0          5s    nginx
    deployment-example-7cf7d6dbc8-dzpgg   1/1     Running   0          18m   apache
    deployment-example-7cf7d6dbc8-r2qz8   1/1     Running   0          18m   nginx
    deployment-example-7cf7d6dbc8-sx4mv   1/1     Running   0          18m   nginx
    deployment-example-7cf7d6dbc8-v9s2d   1/1     Running   0          18m   nginx
    [k8s@server1 ~]$ kubectl delete pod deployment-example-7cf7d6dbc8-dzpgg 
    pod "deployment-example-7cf7d6dbc8-dzpgg" deleted
    [k8s@server1 ~]$ kubectl get pod -L app
    NAME                                  READY   STATUS    RESTARTS   AGE     APP
    deployment-example-7cf7d6dbc8-b26t7   1/1     Running   0          5m39s   nginx
    deployment-example-7cf7d6dbc8-r2qz8   1/1     Running   0          24m     nginx
    deployment-example-7cf7d6dbc8-sx4mv   1/1     Running   0          24m     nginx
    deployment-example-7cf7d6dbc8-v9s2d   1/1     Running   0          24m     nginx
    [k8s@server1 ~]$ kubectl delete pod deployment-example-7cf7d6dbc8-b26t7 
    pod "deployment-example-7cf7d6dbc8-b26t7" deleted
    [k8s@server1 ~]$ kubectl get pod -L app
    NAME                                  READY   STATUS    RESTARTS   AGE   APP
    deployment-example-7cf7d6dbc8-dx7qd   1/1     Running   0          77s   nginx
    deployment-example-7cf7d6dbc8-r2qz8   1/1     Running   0          25m   nginx
    deployment-example-7cf7d6dbc8-sx4mv   1/1     Running   0          25m   nginx
    deployment-example-7cf7d6dbc8-v9s2d   1/1     Running   0          25m   nginx
    [k8s@server1 ~]$

因为控制器的筛选条件是标签为nginx的容器， 当其中一个容器标签被更改以后，脱离了控制器的控制，又因为控制器设置副本数为4，所以控制器会直接创建一个容器，所以标签为nginx的pod被删以后会自动重建，而标签不为nginx的pod不会自动重建，这就是有没有控制器的区别。如果将apache的标签改回nginx,此时标签为nginx的容器为5个，控制器则会删除多余的容器。

[k8s@server1 ~]$ kubectl get pod -L app
    NAME                                  READY   STATUS    RESTARTS   AGE     APP
    deployment-example-7cf7d6dbc8-9ktfc   1/1     Running   0          4s      nginx
    deployment-example-7cf7d6dbc8-dx7qd   1/1     Running   0          8m31s   apache
    deployment-example-7cf7d6dbc8-r2qz8   1/1     Running   0          32m     nginx
    deployment-example-7cf7d6dbc8-sx4mv   1/1     Running   0          32m     nginx
    deployment-example-7cf7d6dbc8-v9s2d   1/1     Running   0          32m     nginx
    [k8s@server1 ~]$ kubectl label pod deployment-example-7cf7d6dbc8-dx7qd app=nginx --overwrite 
    pod/deployment-example-7cf7d6dbc8-dx7qd labeled
    [k8s@server1 ~]$ kubectl get pod -L app
    NAME                                  READY   STATUS        RESTARTS   AGE     APP
    deployment-example-7cf7d6dbc8-9ktfc   1/1     Running       0          19s     nginx
    deployment-example-7cf7d6dbc8-dx7qd   1/1     Terminating   0          8m46s   nginx
    deployment-example-7cf7d6dbc8-r2qz8   1/1     Running       0          33m     nginx
    deployment-example-7cf7d6dbc8-sx4mv   1/1     Running       0          33m     nginx
    deployment-example-7cf7d6dbc8-v9s2d   1/1     Running       0          33m     nginx
    [k8s@server1 ~]$ kubectl get pod -L app
    NAME                                  READY   STATUS    RESTARTS   AGE     APP
    deployment-example-7cf7d6dbc8-9ktfc   1/1     Running   0          3m25s   nginx
    deployment-example-7cf7d6dbc8-r2qz8   1/1     Running   0          36m     nginx
    deployment-example-7cf7d6dbc8-sx4mv   1/1     Running   0          36m     nginx
    deployment-example-7cf7d6dbc8-v9s2d   1/1     Running   0          36m     nginx

#### Node标签 ####

设置server2 node的标签 disktype=ssd

[k8s@server1 ~]$ kubectl label node server2 
    .bash_history      .bash_profile      .config/           kube-flannel.yaml  nginx.yml          .viminfo           
    .bash_logout       .bashrc            .kube/             .local/            pod.yml            
    [k8s@server1 ~]$ kubectl label node server2 disktype=ssd
    node/server2 labeled
    [k8s@server1 ~]$ kubectl get nodes --show-labels 
    NAME      STATUS   ROLES                  AGE     VERSION   LABELS
    server1   Ready    control-plane,master   2d21h   v1.20.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=server1,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=
    server2   Ready    <none>                 2d20h   v1.20.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=ssd,kubernetes.io/arch=amd64,kubernetes.io/hostname=server2,kubernetes.io/os=linux
    server3   Ready    <none>                 2d9h    v1.20.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=server3,kubernetes.io/os=linux

设置控制器把pod调度到带有disktype=ssd的node上

都调度到了server2上

[k8s@server1 ~]$ kubectl get pod -o wide
    NAME                                  READY   STATUS    RESTARTS   AGE     IP            NODE      NOMINATED NODE   READINESS GATES
    deployment-example-54b8d4d9f6-757ln   1/1     Running   0          3m14s   10.244.1.24   server2   <none>           <none>
    deployment-example-54b8d4d9f6-8rq5r   1/1     Running   0          3m14s   10.244.1.23   server2   <none>           <none>
    deployment-example-54b8d4d9f6-qbwlq   1/1     Running   0          3m8s    10.244.1.25   server2   <none>           <none>
    deployment-example-54b8d4d9f6-vlqgc   1/1     Running   0          3m6s    10.244.1.26   server2   <none>           <none>

将server2标签去掉

[k8s@server1 ~]$ kubectl label nodes server2 disktype-
    node/server2 labeled
    [k8s@server1 ~]$ kubectl get nodes --show-labels                        
    NAME      STATUS   ROLES                  AGE     VERSION   LABELS
    server1   Ready    control-plane,master   2d21h   v1.20.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=server1,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=
    server2   Ready    <none>                 2d20h   v1.20.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=server2,kubernetes.io/os=linux
    server3   Ready    <none>                 2d10h   v1.20.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=server3,kubernetes.io/os=linux

此时将副本数改为8个

[k8s@server1 ~]$ kubectl apply -f nginx.yml 
    deployment.apps/deployment-example configured
    [k8s@server1 ~]$ kubectl get pod -o wide
    NAME                                  READY   STATUS    RESTARTS   AGE   IP            NODE      NOMINATED NODE   READINESS GATES
    deployment-example-54b8d4d9f6-757ln   1/1     Running   0          10m   10.244.1.24   server2   <none>           <none>
    deployment-example-54b8d4d9f6-8rq5r   1/1     Running   0          10m   10.244.1.23   server2   <none>           <none>
    deployment-example-54b8d4d9f6-bs5w7   0/1     Pending   0          5s    <none>        <none>    <none>           <none>
    deployment-example-54b8d4d9f6-hqvmf   0/1     Pending   0          5s    <none>        <none>    <none>           <none>
    deployment-example-54b8d4d9f6-p25cc   0/1     Pending   0          5s    <none>        <none>    <none>           <none>
    deployment-example-54b8d4d9f6-qbwlq   1/1     Running   0          10m   10.244.1.25   server2   <none>           <none>
    deployment-example-54b8d4d9f6-vlqgc   1/1     Running   0          10m   10.244.1.26   server2   <none>           <none>
    deployment-example-54b8d4d9f6-w9llw   0/1     Pending   0          5s    <none>        <none>    <none>           <none>
    [k8s@server1 ~]$ kubectl describe pod deployment-example-54b8d4d9f6-bs5w7 
    Events:
      Type     Reason            Age                From               Message
      ----     ------            ----               ----               -------
      Warning  FailedScheduling  34s (x2 over 34s)  default-scheduler  0/3 nodes are available: 1 node(s) had taint {
        node-role.kubernetes.io/master: }, that the pod didn't tolerate, 2 node(s) didn't match Pod's node affinity.

再给server3加上标签

[k8s@server1 ~]$ kubectl label nodes server3 disktype=ssd
    node/server3 labeled
    [k8s@server1 ~]$ kubectl get nodes --show-labels 
    NAME      STATUS   ROLES                  AGE     VERSION   LABELS
    server1   Ready    control-plane,master   2d21h   v1.20.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=server1,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=
    server2   Ready    <none>                 2d21h   v1.20.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=server2,kubernetes.io/os=linux
    server3   Ready    <none>                 2d10h   v1.20.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disktype=ssd,kubernetes.io/arch=amd64,kubernetes.io/hostname=server3,kubernetes.io/os=linux

[k8s@server1 ~]$ kubectl get pod -o wide
    NAME                                  READY   STATUS    RESTARTS   AGE   IP            NODE      NOMINATED NODE   READINESS GATES
    deployment-example-54b8d4d9f6-757ln   1/1     Running   0          36m   10.244.1.24   server2   <none>           <none>
    deployment-example-54b8d4d9f6-8rq5r   1/1     Running   0          36m   10.244.1.23   server2   <none>           <none>
    deployment-example-54b8d4d9f6-bs5w7   1/1     Running   0          26m   10.244.3.18   server3   <none>           <none>
    deployment-example-54b8d4d9f6-hqvmf   1/1     Running   0          26m   10.244.3.19   server3   <none>           <none>
    deployment-example-54b8d4d9f6-p25cc   1/1     Running   0          26m   10.244.3.20   server3   <none>           <none>
    deployment-example-54b8d4d9f6-qbwlq   1/1     Running   0          36m   10.244.1.25   server2   <none>           <none>
    deployment-example-54b8d4d9f6-vlqgc   1/1     Running   0          36m   10.244.1.26   server2   <none>           <none>
    deployment-example-54b8d4d9f6-w9llw   1/1     Running   0          26m   10.244.3.21   server3   <none>           <none>

可以发现k8s node上的标签只会影响未调度的pod，对已经调度的pod不会生效  
Pod 在其生命周期中只会被调度一次。 一旦 Pod 被调度（分派）到某个节点，Pod 会一直在该节点运行，直到 Pod 停止或者 被终止。

#### Pod的状态及生命周期 ####

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzQxNDAyNQ_size_16_color_FFFFFF_t_70 1]

#### Init容器 ####

[官方文档][Link 1]  
每个 Pod 中可以包含多个容器， 应用运行在这些容器里面，同时 Pod 也可以有一个或多个先于应用容器启动的 Init 容器。  
Init 容器与普通的容器非常像，除了如下两点：

*  它们总是运行到完成。
 *  每个都必须在下一个启动之前成功完成。

如果 Pod 的 Init 容器失败，kubelet 会不断地重启该 Init 容器直到该容器成功为止。 然而，如果 Pod 对应的 restartPolicy 值为 “Never”，Kubernetes 不会重新启动 Pod。

apiVersion: v1
    Kind: Pod
    metadata:
      name: myapp-pod
      labels:
        app: myapp
    spec:
      containers:
      - name: myapp-container
        image: nginx
        imagePullPolicy: IfNotPresent
        initContainers:
          - name: init-myservices
            image: busyboxplus
            imagePullPolicy: IfNotPresent
            command: ['sh', '-c', "until nslookup myservice.default.svc.cluster.local; do echo waiting for myservices; sleep 2; done"]

启动后 kubectl describe pod

init-myservices:
        Container ID:  docker://fe8985e5895ea8e7557b74c86f298e4a3405396b0b98cf58a86ff8f7397683d0
        Image:         busyboxplus
        Image ID:      docker-pullable://busyboxplus@sha256:9d1c242c1fd588a1b8ec4461d33a9ba08071f0cc5bb2d50d4ca49e430014ab06
        Port:          <none>
        Host Port:     <none>
        Command:
          sh
          -c
          until nslookup myservice.default.svc.cluster.local; do echo waiting for myservices; sleep 2; done
        State:          Running
          Started:      Sun, 27 Dec 2020 14:22:42 +0800
        Ready:          False
        Restart Count:  0
        Environment:    <none>
        Mounts:
          /var/run/secrets/kubernetes.io/serviceaccount from default-token-4dd4l (ro)

![在这里插入图片描述][20201227142931186.png]  
创建一个service

kind: Service
    apiVersion: v1
    metadata:
      name: myservice
    spec:
      ports:
        - protocol: TCP
          port: 80
          targetPort: 80

[k8s@server1 ~]$ kubectl get svc
    NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
    kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP   14d
    myservice    ClusterIP   10.104.20.158   <none>        80/TCP    33s

解析到域名，容器启动

Init Containers:
      init-myservices:
        Container ID:  docker://fe8985e5895ea8e7557b74c86f298e4a3405396b0b98cf58a86ff8f7397683d0
        Image:         busyboxplus
        Image ID:      docker-pullable://busyboxplus@sha256:9d1c242c1fd588a1b8ec4461d33a9ba08071f0cc5bb2d50d4ca49e430014ab06
        Port:          <none>
        Host Port:     <none>
        Command:
          sh
          -c
          until nslookup myservice.default.svc.cluster.local; do echo waiting for myservices; sleep 2; done
        State:          Terminated
          Reason:       Completed
          Exit Code:    0
          Started:      Sun, 27 Dec 2020 14:22:42 +0800
          Finished:     Sun, 27 Dec 2020 14:31:34 +0800
        Ready:          True
        Restart Count:  0
        Environment:    <none>
        Mounts:
          /var/run/secrets/kubernetes.io/serviceaccount from default-token-4dd4l (ro)

![在这里插入图片描述][20201227143432415.png]

#### 配置探针 ####

[官方文档][Link 2]

##### 存活探针 #####

apiVersion: apps/v1
    kind: Deployment
    metadata: 
      name: deployment-example
    spec:
      replicas: 2
      selector:
        matchLabels:
          app: nginx
      template:
        metadata:
          labels:
            app: nginx
        spec:
          containers:
          - name: nginx
            image: nginx
            imagePullPolicy: IfNotPresent
            livenessProbe:
              tcpSocket:
                port: 80
              initialDelaySeconds: 3
              periodSeconds: 2
              timeoutSeconds: 3
          initContainers:
          - name: init-myservices
            image: busyboxplus
            imagePullPolicy: IfNotPresent
            command: ['sh', '-c', "until nslookup myservice.default.svc.cluster.local; do echo waiting for myservices; sleep 2; done"]

kubectl describe pod

Liveness:       tcp-socket :80 delay=3s timeout=3s period=2s #success=1 #failure=3

停止后容器直接退出  
![在这里插入图片描述][20201227151512347.png]

##### 就绪探针 #####

apiVersion: apps/v1
    kind: Deployment
    metadata: 
      name: deployment-example
    spec:
      replicas: 2
      selector:
        matchLabels:
          app: nginx
      template:
        metadata:
          labels:
            app: nginx
        spec:
          containers:
          - name: nginx
            image: nginx
            imagePullPolicy: IfNotPresent
            livenessProbe:
              tcpSocket:
                port: 80
              initialDelaySeconds: 3
              periodSeconds: 2
              timeoutSeconds: 3
            readinessProbe:
              httpGet:
                path: /test.html
                port: 80
              initialDelaySeconds: 1
              periodSeconds: 3
              timeoutSeconds: 1
          initContainers:
          - name: init-myservices
            image: busyboxplus
            imagePullPolicy: IfNotPresent
            command: ['sh', '-c', "until nslookup myservice.default.svc.cluster.local; do echo waiting for myservices; sleep 2; done"]

虽然容器running但没有ready

[k8s@server1 ~]$ kubectl get pod
    NAME                                  READY   STATUS    RESTARTS   AGE
    deployment-example-557997bffc-5f2js   0/1     Running   0          70s
    deployment-example-557997bffc-tjrgx   0/1     Running   0          70s

kubectl describe pod

Warning  Unhealthy  2m34s (x19 over 3m28s)  kubelet            Readiness probe failed: HTTP probe failed with statuscode: 404

创建test.html

[k8s@server1 ~]$ kubectl exec deployment-example-557997bffc-5f2js -it -- bash
    root@deployment-example-557997bffc-5f2js:/# echo hello world > /usr/share/nginx/html/test.html
    root@deployment-example-557997bffc-5f2js:/# curl localhost/test.html
    hello world
    root@deployment-example-557997bffc-5f2js:/# exit
    [k8s@server1 ~]$ kubectl get pod
    NAME                                  READY   STATUS    RESTARTS   AGE
    deployment-example-557997bffc-5f2js   1/1     Running   0          6m2s
    deployment-example-557997bffc-tjrgx   0/1     Running   0          6m2s

可以发现在node1上ready了  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzQxNDAyNQ_size_16_color_FFFFFF_t_70 2]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzQxNDAyNQ_size_16_color_FFFFFF_t_70]: /images/20221120/8dbd84908724470d80e16ebd6ea68837.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzQxNDAyNQ_size_16_color_FFFFFF_t_70 1]: /images/20221120/b675ac9d0b31434ebdc0682885077cb7.png
[Link 1]: https://kubernetes.io/zh/docs/concepts/workloads/pods/init-containers/
[20201227142931186.png]: https://img-blog.csdnimg.cn/20201227142931186.png
[20201227143432415.png]: https://img-blog.csdnimg.cn/20201227143432415.png
[Link 2]: https://kubernetes.io/zh/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/
[20201227151512347.png]: https://img-blog.csdnimg.cn/20201227151512347.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzQxNDAyNQ_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20201217232725242.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzQxNDAyNQ==,size_16,color_FFFFFF,t_70