kubectl管理Pod-1: 应用生命周期管理

以你之姓@ 2024-04-18 08:35 87阅读 0赞

kubernetes基本架构图：围绕kube-api解耦合的cs架构，而master节点通过kubectl下发应用管理指令  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2V5ZW9mZWFnbGU_size_16_color_FFFFFF_t_70]

# 快速获取kubectl命令帮助 #

*  预创建资源：kubectl create deploy nginx --image=nginx:1.15 -o yaml --dry-run
 *  获取已有资源：kubectl get deploy nginx1 -o yaml
 *  获取资源配置字段名：kubectl explain deploy.spec.template.spec

[root@master ~]# kubectl create deploy nginx --image=nginx:1.15 -o yaml --dry-run
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      labels:
        app: nginx
      name: nginx
    spec:
      replicas: 1
      selector:
        matchLabels:
          app: nginx
      template:
        metadata:
          labels:
            app: nginx
        spec:
          containers:
          - image: nginx:1.15
            name: nginx
            
    [root@master ~]# kubectl get deploy
    NAME     READY   UP-TO-DATE   AVAILABLE   AGE
    nginx1   2/2     2            2           5d22h
    [root@master ~]# kubectl get deploy nginx1 -o yaml
    apiVersion: extensions/v1beta1
    kind: Deployment
    metadata:
      labels:
        app: nginx1
      name: nginx1
      namespace: default
    spec:
      replicas: 2
      selector:
        matchLabels:
          app: nginx1
      template:
        metadata:
          labels:
            app: nginx1
        spec:
          containers:
          - image: nginx:1.15
            imagePullPolicy: IfNotPresent
            name: nginx1
            resources: {}
          restartPolicy: Always
          
    [root@master ~]# kubectl explain deploy.spec.template.spec.containers.imagePullPolicy
    KIND:     Deployment
    VERSION:  extensions/v1beta1
    FIELD:    imagePullPolicy <string>
    DESCRIPTION:
         Image pull policy. One of Always, Never, IfNotPresent. Defaults to Always
         if :latest tag is specified, or IfNotPresent otherwise. Cannot be updated.
         More info:
         https://kubernetes.io/docs/concepts/containers/images#updating-images

# 1, 创建应用(pod-controller, service) #

![在这里插入图片描述][20190904095105503.png]

## a, 使用命令行 ##

此处nginx被分配到: 一个副本，在node2上创建

#1, 命令直接创建：默认pod是一个副本
    [root@master yamls]# kubectl create deployment nginx --image=nginx:1.15
    deployment.apps/nginx created
    
    #2, 查看创建的对象：pod,deploy,replicaset;  service
    [root@master yamls]# kubectl get  all -o wide
    NAME                         READY   STATUS    RESTARTS   AGE   IP            NODE    NOMINATED NODE   READINESS GATES
    pod/nginx-5ddcc6cb74-qvtb7   1/1     Running   0          10s   10.244.1.27   node2   <none>           <none>
    NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE   SELECTOR
    
    deployment.apps/nginx   1/1     1            1           10s   nginx        nginx:1.15   app=nginx
    NAME                               DESIRED   CURRENT   READY   AGE   CONTAINERS   IMAGES       SELECTOR
    replicaset.apps/nginx-5ddcc6cb74   1         1         1       10s   nginx        nginx:1.15   app=nginx,pod-template-hash=5ddcc6cb74
    
    service/kubernetes   ClusterIP   10.1.0.1     <none>        443/TCP   16h   <none>
    NAME                    READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES       SELECTOR

## b, 使用yaml文件 ##

########## 单独创建pod: 没有控制器管理，删除pod就不再创建了######
    ## 创建命令： kubectl create -f pod.yaml    ##kubectl apply -f pod.yaml :重新配置应用更改
    [root@master yamls]# cat pod.yaml 
    apiVersion: v1
    kind: Pod
    metadata:
      name: nginx1
      namespace: default
    spec:
      containers:
      - image: nginx
        imagePullPolicy: IfNotPresent
        name: nginx1
    
    ########## 通过控制器管理pod: 删除pod会重新创建，直到满足副本数######
    ## 创建命令： kubectl create -f deploy.yaml    ##kubectl apply -f deploy.yaml :重新配置应用更改
    [root@master yamls]# cat deploy.yaml 
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: nginx1
      namespace: default
    spec:
      replicas: 1
      selector:
        matchLabels:
          app: nginx1
      template:
        metadata:
          labels:
            app: nginx1
        spec:
          containers:
          - image: nginx
            imagePullPolicy: IfNotPresent
            name: nginx1

# 2,发布应用：暴露服务访问接口 #

## a, 使用命令行 ##

#1, ClusterIp类型的服务：只供集群内部访问 ( 默认ClusterIp)
    [root@master yamls]# kubectl expose deployment.apps/nginx --port=80 --name=nginx-service-clusterip
    service/nginx-service-clusterip exposed
    [root@master yamls]# kubectl expose deployment.apps/nginx --port=80 --type=NodePort --name=nginx-service-nodeport
    
    [root@master yamls]# 
    [root@master yamls]# kubectl get all -o wide
    NAME                         READY   STATUS    RESTARTS   AGE   IP            NODE    NOMINATED NODE   READINESS GATES
    pod/nginx-5ddcc6cb74-qvtb7   1/1     Running   0          15m   10.244.1.27   node2   <none>           <none>
    
    NAME                              TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)   AGE   SELECTOR
    service/nginx-service-clusterip   ClusterIP   10.1.219.85   <none>        80/TCP    26s   app=nginx
    service/nginx-service-nodeport    NodePort    10.1.122.82   <none>        80:30408/TCP   40s    app=nginx
    
    #2, 通过该接口访问服务: clusterip:80 -->pod在node2上，相应的服务也会在node2上被监听
    [root@master yamls]# ssh node2 curl 10.1.219.85
      % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                     Dload  Upload   Total   Spent    Left  Speed
    100   612  100   612    0     0   398k      0 <!DOCTYPE html>-- --:--:--     0
    <html>
    <head>
    <title>Welcome to nginx!</title>
    
    #3, 访问该接口访问服务:  节点ip:暴露的服务端口
    [root@master yamls]# curl node2:30408
    <!DOCTYPE html>
    <html>
    <head>
    <title>Welcome to nginx!</title>

## b, 使用yaml文件 ##

## 创建命令： kubectl create -f service.yaml    ##kubectl apply -f service.yaml :重新配置应用更改
    [root@master yamls]# cat service.yaml 
    apiVersion: v1
    kind: Service
    metadata:
      name: nginx1
      namespace: default
    spec:
      ports:
      - nodePort: 31000
        port: 80
        protocol: TCP
        targetPort: 80
      selector:
        app: nginx1
      type: NodePort
      #type: ClusterIp

# 3, 应用滚动更新/回滚：版本迭代 #

#1,查看要升级的应用
    [root@master yamls]# kubectl get deploy
    NAME    READY   UP-TO-DATE   AVAILABLE   AGE
    nginx   1/1     1            1           28m
    [root@master yamls]# kubectl set image deploy nginx nginx=1.17
    deployment.extensions/nginx image updated
    [root@master yamls]# kubectl get pod
    NAME                     READY   STATUS              RESTARTS   AGE
    nginx-57f7c6746-l6rcb    0/1     ContainerCreating   0          7s
    nginx-5ddcc6cb74-qvtb7   1/1     Running             0          29m

# 4, 应用下线：删除 #

#模拟docker删除所有容器， 可以用如下命令删除所有应用，留下空白的集群环境
     kubectl delete  $(kubectl get all |awk '{print $1}' |egrep -vi "name|kubernetes")
     kubectl get deploy,pod |grep -vi name|awk '{print $1}'|xargs kubectl delete 
    
    #删除deploy --> replicat-set, pod, 删除service
     kubectl delte deployment.apps/nginx1  #kubectl delete deploy nginx1
     kubectl delte service/service-nginx1  #kubectl delete service service-nginx1

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2V5ZW9mZWFnbGU_size_16_color_FFFFFF_t_70]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/bc86c6bc51764544a28ed5f8a29f26b6.png
[20190904095105503.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/17/93edfe77056a4159b5073b34ced89b85.png