[K8S] Deployment滚动更新和回滚、水平伸缩

约定不等于承诺〃 2022-09-04 13:51 173阅读 0赞

\- 创建Deployment  
\- 滚动更新  
\- ReplicaSet  
\- 回滚  
\- 水平伸缩

**@创建Deployment**

首先创建一个deployment，pod副本数为3，使用镜像nginx:1.19，并创建服务

test-deploy-svc.yaml 的内容如下

apiVersion: apps/v1
    kind: Deployment
    metadata:
      labels:
        app: web
      name: web
      namespace: default
    spec:
      replicas: 3
      selector:
        matchLabels:
          app: web
      strategy: {}
      template:
        metadata:
          labels:
            app: web
        spec:
          containers:
          - image: nginx:1.19
            name: nginx
    ---
    apiVersion: v1
    kind: Service
    metadata:
      labels:
        app: web
      name: web
    spec:
      ports:
      - port: 80
        protocol: TCP
        targetPort: 80
      selector:
        app: web
      type: NodePort

创建deployment

[root@k8s-master ~]# kubectl apply -f test-deploy-svc.yaml
    deployment.apps/web created
    service/web created
    [root@k8s-master ~]#

查看svc的NodePort，为31147

[root@k8s-master ~]# kubectl get svc -o wide
    NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE   SELECTOR
    kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP        19d   <none>
    web          NodePort    10.99.203.162   <none>        80:31147/TCP   49s   app=web
    [root@k8s-master ~]#

查询svc关联的pod

[root@k8s-master ~]# kubectl get endpoints
    NAME         ENDPOINTS                                           AGE
    kubernetes   192.168.231.121:6443                                19d
    web          10.244.169.161:80,10.244.36.84:80,10.244.36.88:80   2m28s
    [root@k8s-master ~]#

浏览器打开主页，http://<cluster中任意node的地址>:31147

同时打开控制台，查看nginx版本，这里是1.19.10

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5X2hoeHg_size_16_color_FFFFFF_t_70][]

**@滚动更新**

方法1： kubectl set image deployment web nginx=nginx:1.20

[root@k8s-master ~]# kubectl set image deployment web nginx=nginx:1.20
    deployment.apps/web image updated
    [root@k8s-master ~]#

刷新浏览器页面浏览器 版本更新为nginx/1.20.1

**pod在这个过程会滚动更新**（下一个方法中详述）；**查看endpoints，svc关联的pod地址变了**

[root@k8s-master ~]# kubectl get endpoints
    NAME         ENDPOINTS                                           AGE
    kubernetes   192.168.231.121:6443                                19d
    web          10.244.169.160:80,10.244.36.81:80,10.244.36.82:80   13m
    [root@k8s-master ~]#

方法2：修改yaml文件，再次apply，将版本改为1.21

[root@k8s-master ~]# grep image test-deploy-svc.yaml
          - image: nginx:1.19
    [root@k8s-master ~]# vim test-deploy-svc.yaml
    [root@k8s-master ~]# grep image test-deploy-svc.yaml
          - image: nginx:1.21
    [root@k8s-master ~]#

先记录此刻1.20版本pod的NAME和IP

[root@k8s-master ~]# kubectl get pod -o wide
    NAME                   READY   STATUS    RESTARTS   AGE     IP               NODE        NOMINATED NODE   READINESS GATES
    web-7f5844f89c-6sdxt   1/1     Running   0          5m28s   10.244.169.160   k8s-node2   <none>           <none>
    web-7f5844f89c-cxqjf   1/1     Running   0          5m29s   10.244.36.82     k8s-node1   <none>           <none>
    web-7f5844f89c-m6655   1/1     Running   0          5m26s   10.244.36.81     k8s-node1   <none>           <none>
    [root@k8s-master ~]#

执行kubectl apply -f test-deploy-svc.yaml更新

[root@k8s-master ~]# kubectl apply -f test-deploy-svc.yaml
    deployment.apps/web configured
    service/web unchanged
    [root@k8s-master ~]#

不断使用命令kubectl get pod -o wide查看pod创建情况

\--> 正在创建一个新pod，其状态为ContainerCreating

[root@k8s-master ~]# kubectl get pod -o wide
    NAME                   READY   STATUS              RESTARTS   AGE    IP               NODE        NOMINATED NODE   READINESS GATES
    web-7f5844f89c-6sdxt   1/1     Running             0          6m7s   10.244.169.160   k8s-node2   <none>           <none>
    web-7f5844f89c-cxqjf   1/1     Running             0          6m8s   10.244.36.82     k8s-node1   <none>           <none>
    web-7f5844f89c-m6655   1/1     Running             0          6m5s   10.244.36.81     k8s-node1   <none>           <none>
    web-d779974b6-j72dv    0/1     ContainerCreating   0          4s     <none>           k8s-node1   <none>           <none>
    [root@k8s-master ~]#

\--> 第一个新pod状态变为Running，一个旧pod进入Terminating，同时创建第二个新pod

[root@k8s-master ~]# kubectl get pod -o wide
    NAME                   READY   STATUS              RESTARTS   AGE     IP               NODE        NOMINATED NODE   READINESS GATES
    web-7f5844f89c-6sdxt   1/1     Running             0          6m22s   10.244.169.160   k8s-node2   <none>           <none>
    web-7f5844f89c-cxqjf   1/1     Running             0          6m23s   10.244.36.82     k8s-node1   <none>           <none>
    web-7f5844f89c-m6655   1/1     Terminating         0          6m20s   10.244.36.81     k8s-node1   <none>           <none>
    web-d779974b6-j72dv    1/1     Running             0          19s     10.244.36.90     k8s-node1   <none>           <none>
    web-d779974b6-j9fkf    0/1     ContainerCreating   0          0s      <none>           k8s-node2   <none>           <none>
    [root@k8s-master ~]#

……

\--> 创建了三个新pod，旧的三个pod处于Terminating状态

[root@k8s-master ~]# kubectl get pod -o wide
    NAME                   READY   STATUS        RESTARTS   AGE     IP               NODE        NOMINATED NODE   READINESS GATES
    web-7f5844f89c-6sdxt   0/1     Terminating   0          6m25s   10.244.169.160   k8s-node2   <none>           <none>
    web-7f5844f89c-cxqjf   1/1     Terminating   0          6m26s   10.244.36.82     k8s-node1   <none>           <none>
    web-7f5844f89c-m6655   0/1     Terminating   0          6m23s   10.244.36.81     k8s-node1   <none>           <none>
    web-d779974b6-9nmb6    1/1     Running       0          2s      10.244.36.91     k8s-node1   <none>           <none>
    web-d779974b6-j72dv    1/1     Running       0          22s     10.244.36.90     k8s-node1   <none>           <none>
    web-d779974b6-j9fkf    1/1     Running       0          3s      10.244.169.164   k8s-node2   <none>           <none>
    [root@k8s-master ~]#

……

\--> 三个pod全部"更新"为新版本

[root@k8s-master ~]# kubectl get pod -o wide
    NAME                  READY   STATUS    RESTARTS   AGE   IP               NODE        NOMINATED NODE   READINESS GATES
    web-d779974b6-9nmb6   1/1     Running   0          11s   10.244.36.91     k8s-node1   <none>           <none>
    web-d779974b6-j72dv   1/1     Running   0          31s   10.244.36.90     k8s-node1   <none>           <none>
    web-d779974b6-j9fkf   1/1     Running   0          12s   10.244.169.164   k8s-node2   <none>           <none>
    [root@k8s-master ~]#

以上步骤可以看到pod分配了新的IP，查看endpoints也可以观察到service绑定的pod地址更新了

[root@k8s-master ~]# kubectl get ep
    NAME         ENDPOINTS                                           AGE
    kubernetes   192.168.231.121:6443                                19d
    web          10.244.169.164:80,10.244.36.90:80,10.244.36.91:80   30m
    [root@k8s-master ~]#

刷新浏览器页面，查看nginx版本更新为 nginx/1.21.1

**@ReplicaSet**

常用命令：

kubectl get replicaset  
kubectl describe deployment <deployment name>  
kubectl describe <replicaset name>

**滚动升级的执行者**是 控制器 replicaset(rs) ，**管理pod的副本数量**，也会**记录发布的版本**

用命令kubectl get replicaset查看rs，最后一行期望副本数为3的web-d779974b6是最近一次的部署，对应上述最新的pod，可以发现 **pod NAME = deployment NAME + rs NAME + 随机字符串**

[root@k8s-master ~]# kubectl get replicaset
    NAME             DESIRED   CURRENT   READY   AGE
    web-7f5844f89c   0         0         0       30m
    web-bc7cc9f65    0         0         0       40m
    web-d779974b6    3         3         3       24m
    [root@k8s-master ~]#

查看deployment详细信息可以看到滚动升级的过程，关注下述最后的Events部分

(但是过一段时间再执行就会变成 Events:  <none>)

[root@k8s-master ~]# kubectl describe deployment web
    Name:                   web
    Namespace:              default
    CreationTimestamp:      Sat, 14 Aug 2021 14:32:35 +0800
    Labels:                 app=web
    Annotations:            deployment.kubernetes.io/revision: 3
    Selector:               app=web
    Replicas:               3 desired | 3 updated | 3 total | 3 available | 0 unavailable
    StrategyType:           RollingUpdate
    MinReadySeconds:        0
    RollingUpdateStrategy:  25% max unavailable, 25% max surge
    Pod Template:
      Labels:  app=web
      Containers:
       nginx:
        Image:        nginx:1.21
        Port:         <none>
        Host Port:    <none>
        Environment:  <none>
        Mounts:       <none>
      Volumes:        <none>
    Conditions:
      Type           Status  Reason
      ----           ------  ------
      Available      True    MinimumReplicasAvailable
      Progressing    True    NewReplicaSetAvailable
    OldReplicaSets:  <none>
    NewReplicaSet:   web-d779974b6 (3/3 replicas created)
    Events:
      Type    Reason             Age                From                   Message
      ----    ------             ----               ----                   -------
      Normal  ScalingReplicaSet  59m                deployment-controller  Scaled up replica set web-d779974b6 to 1
      Normal  ScalingReplicaSet  58m                deployment-controller  Scaled down replica set web-7f5844f89c to 2
      Normal  ScalingReplicaSet  58m                deployment-controller  Scaled up replica set web-d779974b6 to 2
      Normal  ScalingReplicaSet  58m (x3 over 58m)  deployment-controller  (combined from similar events): Scaled down replica set web-7f5844f89c to 0
    [root@k8s-master ~]#

查看rs信息也可以看到标记的版本

[root@k8s-master ~]# kubectl describe rs web-d779974b6
    Name:           web-d779974b6
    Namespace:      default
    Selector:       app=web,pod-template-hash=d779974b6
    Labels:         app=web
                    pod-template-hash=d779974b6
    Annotations:    deployment.kubernetes.io/desired-replicas: 3
                    deployment.kubernetes.io/max-replicas: 4
                    deployment.kubernetes.io/revision: 3
    Controlled By:  Deployment/web
    Replicas:       3 current / 3 desired
    Pods Status:    3 Running / 0 Waiting / 0 Succeeded / 0 Failed
    Pod Template:
      Labels:  app=web
               pod-template-hash=d779974b6
      Containers:
       nginx:
        Image:        nginx:1.21
        Port:         <none>
        Host Port:    <none>
        Environment:  <none>
        Mounts:       <none>
      Volumes:        <none>
    Events:           <none>
    [root@k8s-master ~]#

**@回滚**

常用命令：  
kubectl rollout history deployment web  
kubectl rollout undo deployment web  
kubectl rollout undo deployment web --to-revision=<num>

查看历史发布版本

[root@k8s-master ~]# kubectl rollout history deployment web
    deployment.apps/web
    REVISION  CHANGE-CAUSE
    1         <none>
    2         <none>
    3         <none>
    
    [root@k8s-master ~]#

说明：部署的时候加上--record CHANGE-CAUSE会有记录

[root@k8s-master ~]# kubectl set image deployment web nginx=nginx:1.21 --record
    deployment.apps/web image updated
    [root@k8s-master ~]# kubectl rollout history deployment web
    deployment.apps/web
    REVISION  CHANGE-CAUSE
    1         <none>
    4         <none>
    5         kubectl set image deployment web nginx=nginx:1.21 --record=true
    
    [root@k8s-master ~]#

回滚到上一个版本（常用）

[root@k8s-master ~]# kubectl rollout undo deployment web
    deployment.apps/web rolled back
    [root@k8s-master ~]#

可以查看到rs的变化

[root@k8s-master ~]# kubectl get rs
    NAME             DESIRED   CURRENT   READY   AGE
    web-7f5844f89c   3         3         3       88m
    web-bc7cc9f65    0         0         0       98m
    web-d779974b6    0         0         0       82m
    [root@k8s-master ~]#

**@水平伸缩**

方法1：修改yaml文件中replicas的值

方法2：使用命令 kubectl scale deployment web --replicas=<pod num>

例如，使用方法2缩容到2个pod

[root@k8s-master ~]# kubectl scale deployment web --replicas=2
    deployment.apps/web scaled
    [root@k8s-master ~]# kubectl get pod
    NAME                  READY   STATUS        RESTARTS   AGE
    web-d779974b6-6rctw   1/1     Running       0          5m41s
    web-d779974b6-dv7fh   1/1     Running       0          5m40s
    web-d779974b6-j6n9r   0/1     Terminating   0          5m38s
    [root@k8s-master ~]#
    [root@k8s-master ~]# kubectl get pod
    NAME                  READY   STATUS    RESTARTS   AGE
    web-d779974b6-6rctw   1/1     Running   0          5m50s
    web-d779974b6-dv7fh   1/1     Running   0          5m49s
    [root@k8s-master ~]#
    [root@k8s-master ~]# kubectl get rs
    NAME             DESIRED   CURRENT   READY   AGE
    web-7f5844f89c   0         0         0       128m
    web-bc7cc9f65    0         0         0       138m
    web-d779974b6    2         2         2       122m
    [root@k8s-master ~]#

再使用方法1扩容到3个pod

[root@k8s-master ~]# kubectl apply -f test-deploy-svc.yaml
    deployment.apps/web configured
    service/web unchanged
    [root@k8s-master ~]# kubectl get pod
    NAME                  READY   STATUS    RESTARTS   AGE
    web-d779974b6-6rctw   1/1     Running   0          7m34s
    web-d779974b6-dv7fh   1/1     Running   0          7m33s
    web-d779974b6-n8p6d   1/1     Running   0          5s
    [root@k8s-master ~]#
    [root@k8s-master ~]# kubectl get rs
    NAME             DESIRED   CURRENT   READY   AGE
    web-7f5844f89c   0         0         0       131m
    web-bc7cc9f65    0         0         0       141m
    web-d779974b6    3         3         3       125m
    [root@k8s-master ~]#

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