Kubernetes学习之Deployment控制器

最新推荐文章于 2024-11-07 22:12:53 发布

Micky_Yang

最新推荐文章于 2024-11-07 22:12:53 发布

阅读量486

点赞数

分类专栏： Kubernetes学习

本文链接：https://blog.youkuaiyun.com/Micky_Yang/article/details/107592403

版权

Kubernetes学习专栏收录该内容

26 篇文章

订阅专栏

本文介绍了Kubernetes中的Deployment控制器，它提供声明式的更新方式来管理Pod和Replica Set。内容涵盖Deployment的工作原理、应用场景，如滚动更新、动态扩缩容、回滚等操作。还详细阐述了如何创建、查看、操作Deployment资源，以及如何进行Pod镜像的滚动更新和回滚，最后讨论了Deployment的清理策略。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

一、认识Deployment控制器
　　Deployment控制器为Pod和Replica Set控制器提供声明式的更新；你只需要在Deployment中描述你想要的目标状态是什么，Deployment Controller就会帮你将Pod和Relica Set控制器的实际状态改变到你的目标状态。你也可以定义一个新的Deployment，也可以创建一个新的替换旧的Deployment控制器。
　　当我们在使用Deployment控制器做滚动更新时，Deployment控制器首先会创建出一个新的ReplicaSet控制器，在新的ReplicaSet控制器上创建出新的Pod；并且通过一定的频率，将老的ReplicaSet控制器上的Pod发送退出信号；但是无论如何更新，老的ReplicaSet控制器上的Pod副本数和新的ReplicaSet副本数必须要满足Deployment控制器所规定的数量；当老的ReplicaSet控制器中的Pod被用户访问完毕时，便会退出；新的用户访问会被调度到新的ReplicaSet控制器下的Pod上。
在这里插入图片描述

二、Deployment典型的应用场景如下

使用Deployment控制器来创建ReplicaSet，ReplicationSet在后台创建Pod；检查启动状态，看它是成功还是失败。
通过更新Deployment控制器中的PodTemplateSpec字段来声明Pod的新状态。这会创建一个新的ReplicationSet，Deployment控制器会按照自己所控制的速率将Pod从旧的ReplicaSet中移动到新的ReplicaSet中。
如果当前状态不稳定，回滚到之前的Deployment revision，每次回滚都会更新Deployment的revision。
支持动态扩缩容，扩容Deployment控制器以满足更高的负载。
暂停Deployment控制器来应用PodTemplateSpec的多个修复，然后恢复上线。
根据Deployment控制器的状态来判断上线是否失败了。
定时清理不必要的ReplicaSet

三、Deployment使用操作

1）创建Deployment资源

]# cat deploy-demo.yaml 
apiVersion: apps/v1
kind: Deployment
metadata: 
  name: myapp-deploy
  namespace: default
spec: 
  replicas: 3
  selector:
    matchLabels:
      app: myapp
      release: canary
  template:
    metadata:
      labels:
        app: myapp
        release: canary
    spec:
      containers:
      - name: myapp
        image: ikubernetes/myapp:v1
        imagePullPolicy: IfNotPresent
        ports:
        - name: http
          containerPort: 80

]# kubectl apply -f deploy-demo.yaml 
deployment.apps/myapp-deploy created

2）查看Deployment资源

]# kubectl get deploy -o wide 
NAME           READY   UP-TO-DATE   AVAILABLE   AGE     CONTAINERS   IMAGES                 SELECTOR
myapp-deploy   3/3     3            3           2m35s   myapp        ikubernetes/myapp:v1   app=myapp,release=canary

]# kubectl get rs -o wide 
NAME                      DESIRED   CURRENT   READY   AGE     CONTAINERS   IMAGES                 SELECTOR
myapp-deploy-65fb6c8459   3         3         3       2m43s   myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary

]# kubectl get pods -o wide 
NAME                            READY   STATUS    RESTARTS   AGE     IP            NODE    NOMINATED NODE   READINESS GATES
myapp-deploy-65fb6c8459-bkcbj   1/1     Running   0          3m49s   10.244.1.28   node1   <none>           <none>
myapp-deploy-65fb6c8459-c44fs   1/1     Running   0          3m49s   10.244.1.27   node1   <none>           <none>
myapp-deploy-65fb6c8459-fbbl7   1/1     Running   0          3m49s   10.244.2.10   node2   <none>           <none>

3）访问pod资源

]# curl 10.244.1.28
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

]# curl 10.244.1.27
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

]# curl 10.244.2.10
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

4）查看Deoloyment和ReplicaSet的详细信息

]# kubectl describe deployment myapp-deploy
Name:                   myapp-deploy
Namespace:              default
CreationTimestamp:      Sun, 26 Jul 2020 13:50:09 +0800
Labels:                 <none>
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=myapp,release=canary
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=myapp
           release=canary
  Containers:
   myapp:
    Image:        ikubernetes/myapp:v1
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Progressing    True    NewReplicaSetAvailable
  Available      True    MinimumReplicasAvailable
OldReplicaSets:  <none>
NewReplicaSet:   myapp-deploy-65fb6c8459 (3/3 replicas created)
Events:
  Type    Reason             Age    From                   Message
  ----    ------             ----   ----                   -------
  Normal  ScalingReplicaSet  6m21s  deployment-controller  Scaled up replica set myapp-deploy-65fb6c8459 to 3


]# kubectl describe rs myapp-deploy-65fb6c8459
Name:           myapp-deploy-65fb6c8459
Namespace:      default
Selector:       app=myapp,pod-template-hash=65fb6c8459,release=canary
Labels:         app=myapp
                pod-template-hash=65fb6c8459
                release=canary
Annotations:    deployment.kubernetes.io/desired-replicas: 3
                deployment.kubernetes.io/max-replicas: 4
                deployment.kubernetes.io/revision: 1
Controlled By:  Deployment/myapp-deploy
Replicas:       3 current / 3 desired
Pods Status:    3 Running / 0 Waiting / 0 Succeeded / 0 Failed
Pod Template:
  Labels:  app=myapp
           pod-template-hash=65fb6c8459
           release=canary
  Containers:
   myapp:
    Image:        ikubernetes/myapp:v1
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Events:
  Type    Reason            Age   From                   Message
  ----    ------            ----  ----                   -------
  Normal  SuccessfulCreate  8m8s  replicaset-controller  Created pod: myapp-deploy-65fb6c8459-c44fs
  Normal  SuccessfulCreate  8m8s  replicaset-controller  Created pod: myapp-deploy-65fb6c8459-bkcbj
  Normal  SuccessfulCreate  8m8s  replicaset-controller  Created pod: myapp-deploy-65fb6c8459-fbbl7

5）动态扩容Pod副本集

]# kubectl patch deployment myapp-deploy -p '{"spec":{"replicas":5}}' 
deployment.apps/myapp-deploy patched

]# kubectl get pods -w 
NAME                            READY   STATUS    RESTARTS   AGE
myapp-deploy-65fb6c8459-bkcbj   1/1     Running   0          9m21s
myapp-deploy-65fb6c8459-c44fs   1/1     Running   0          9m21s
myapp-deploy-65fb6c8459-fbbl7   1/1     Running   0          9m21s

myapp-deploy-65fb6c8459-2wkfq   0/1     Pending   0          0s
myapp-deploy-65fb6c8459-vtrzk   0/1     Pending   0          0s
myapp-deploy-65fb6c8459-2wkfq   0/1     Pending   0          0s
myapp-deploy-65fb6c8459-vtrzk   0/1     Pending   0          0s
myapp-deploy-65fb6c8459-2wkfq   0/1     ContainerCreating   0          0s
myapp-deploy-65fb6c8459-vtrzk   0/1     ContainerCreating   0          0s
myapp-deploy-65fb6c8459-vtrzk   1/1     Running             0          2s
myapp-deploy-65fb6c8459-2wkfq   1/1     Running             0          2s

Deployment控制器中的Pod资源副本集已经被动态的创建出来，并且不影响原有的Pod资源

6）动态缩容Pod副本集

]# kubectl patch deployment myapp-deploy -p '{"spec":{"replicas":2}}' 
deployment.apps/myapp-deploy patched

[root@master label]# kubectl get pods -w 
NAME                            READY   STATUS    RESTARTS   AGE
myapp-deploy-65fb6c8459-2wkfq   1/1     Running   0          112s
myapp-deploy-65fb6c8459-bkcbj   1/1     Running   0          12m
myapp-deploy-65fb6c8459-c44fs   1/1     Running   0          12m
myapp-deploy-65fb6c8459-fbbl7   1/1     Running   0          12m
myapp-deploy-65fb6c8459-vtrzk   1/1     Running   0          112s

myapp-deploy-65fb6c8459-c44fs   1/1     Terminating   0          13m
myapp-deploy-65fb6c8459-2wkfq   1/1     Terminating   0          3m16s
myapp-deploy-65fb6c8459-vtrzk   1/1     Terminating   0          3m16s
myapp-deploy-65fb6c8459-vtrzk   0/1     Terminating   0          3m19s
myapp-deploy-65fb6c8459-2wkfq   0/1     Terminating   0          3m19s
myapp-deploy-65fb6c8459-c44fs   0/1     Terminating   0          13m
myapp-deploy-65fb6c8459-2wkfq   0/1     Terminating   0          3m20s
myapp-deploy-65fb6c8459-2wkfq   0/1     Terminating   0          3m20s
myapp-deploy-65fb6c8459-c44fs   0/1     Terminating   0          13m
myapp-deploy-65fb6c8459-c44fs   0/1     Terminating   0          13m
myapp-deploy-65fb6c8459-vtrzk   0/1     Terminating   0          3m20s
myapp-deploy-65fb6c8459-vtrzk   0/1     Terminating   0          3m20s

Deployment控制器已经平滑退出了三个副本集，来满足用户所定义的Pod副本数量

7）滚动更新Pod镜像

]# kubectl set image deployment myapp-deploy myapp=ikubernetes/myapp:v2
deployment.apps/myapp-deploy image updated

]# kubectl get rs -w 
NAME                      DESIRED   CURRENT   READY   AGE
myapp-deploy-65fb6c8459   2         2         2       18m

myapp-deploy-559ff5c66    1         0         0       0s
myapp-deploy-559ff5c66    1         0         0       0s
myapp-deploy-559ff5c66    1         1         0       0s
myapp-deploy-559ff5c66    1         1         1       3s
myapp-deploy-65fb6c8459   1         2         2       18m
myapp-deploy-559ff5c66    2         1         1       3s
myapp-deploy-65fb6c8459   1         2         2       18m
myapp-deploy-559ff5c66    2         1         1       3s
myapp-deploy-559ff5c66    2         2         1       3s
myapp-deploy-65fb6c8459   1         1         1       18m
myapp-deploy-559ff5c66    2         2         2       4s
myapp-deploy-65fb6c8459   0         1         1       18m
myapp-deploy-65fb6c8459   0         1         1       18m
myapp-deploy-65fb6c8459   0         0         0       18m

]# kubectl get pods -w 
NAME                            READY   STATUS    RESTARTS   AGE
myapp-deploy-65fb6c8459-bkcbj   1/1     Running   0          15m
myapp-deploy-65fb6c8459-fbbl7   1/1     Running   0          15m

myapp-deploy-559ff5c66-gmgfn    0/1     Pending   0          0s
myapp-deploy-559ff5c66-gmgfn    0/1     Pending   0          0s
myapp-deploy-559ff5c66-gmgfn    0/1     ContainerCreating   0          0s
myapp-deploy-559ff5c66-gmgfn    1/1     Running             0          3s
myapp-deploy-65fb6c8459-bkcbj   1/1     Terminating         0          18m
myapp-deploy-559ff5c66-2sqtc    0/1     Pending             0          0s
myapp-deploy-559ff5c66-2sqtc    0/1     Pending             0          0s
myapp-deploy-559ff5c66-2sqtc    0/1     ContainerCreating   0          0s
myapp-deploy-65fb6c8459-bkcbj   0/1     Terminating         0          18m
myapp-deploy-559ff5c66-2sqtc    1/1     Running             0          1s
myapp-deploy-65fb6c8459-fbbl7   1/1     Terminating         0          18m
myapp-deploy-65fb6c8459-fbbl7   0/1     Terminating         0          18m
myapp-deploy-65fb6c8459-bkcbj   0/1     Terminating         0          18m
myapp-deploy-65fb6c8459-bkcbj   0/1     Terminating         0          18m
myapp-deploy-65fb6c8459-fbbl7   0/1     Terminating         0          18m
myapp-deploy-65fb6c8459-fbbl7   0/1     Terminating         0          18m

]# kubectl get rs -o wide
NAME                      DESIRED   CURRENT   READY   AGE     CONTAINERS   IMAGES                 SELECTOR
myapp-deploy-559ff5c66    2         2         2       5m22s   myapp        ikubernetes/myapp:v2   app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-65fb6c8459   0         0         0       24m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary

通过监视ReplicaSet控制器和Pod资源，可以看见整个Deployment控制器更新的操作；首先Depliyment控制器会创建一个新的ReplicaSet控制器，并在此控制器上创建新的Pod资源对象，然后平滑退出旧的ReplicaSet控制器上的Pod资源；虽然Pod资源被创建调度到了新的ReplicaSet控制器上，但是老的ReplicaSet控制器并不会退出，因为用户可能会做回滚操作，Deployment通过此来做回滚历史版本。

8）访问新的Pod资源对象

]# kubectl get pods -o wide
NAME                           READY   STATUS    RESTARTS   AGE   IP            NODE    NOMINATED NODE   READINESS GATES
myapp-deploy-559ff5c66-5zv6t   1/1     Running   0          23s   10.244.1.35   node1   <none>           <none>
myapp-deploy-559ff5c66-v9qdf   1/1     Running   0          24s   10.244.1.34   node1   <none>           <none>

]# curl 10.244.1.35
Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

]# curl 10.244.1.34
Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

9）查看滚动更新历史

]# kubectl rollout history deployment
deployment.apps/myapp-deploy 
REVISION  CHANGE-CAUSE
1         <none>
2         <none>

10）回滚Pod镜像版本

]# kubectl rollout undo deployment/myapp-deploy --to-revision=1
deployment.apps/myapp-deploy rolled back

]# kubectl get rs -w -o wide
NAME                      DESIRED   CURRENT   READY   AGE     CONTAINERS   IMAGES                 SELECTOR
myapp-deploy-559ff5c66    2         2         2       8m16s   myapp        ikubernetes/myapp:v2   app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-65fb6c8459   0         0         0       27m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary

myapp-deploy-65fb6c8459   0         0         0       29m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-65fb6c8459   1         0         0       29m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-65fb6c8459   1         0         0       29m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-65fb6c8459   1         1         0       29m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-65fb6c8459   1         1         1       29m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-559ff5c66    1         2         2       10m     myapp        ikubernetes/myapp:v2   app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-65fb6c8459   2         1         1       29m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-559ff5c66    1         2         2       10m     myapp        ikubernetes/myapp:v2   app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-65fb6c8459   2         1         1       29m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-65fb6c8459   2         2         1       29m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-559ff5c66    1         1         1       10m     myapp        ikubernetes/myapp:v2   app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-65fb6c8459   2         2         2       29m     myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary
myapp-deploy-559ff5c66    0         1         1       10m     myapp        ikubernetes/myapp:v2   app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-559ff5c66    0         1         1       10m     myapp        ikubernetes/myapp:v2   app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-559ff5c66    0         0         0       10m     myapp        ikubernetes/myapp:v2   app=myapp,pod-template-hash=559ff5c66,release=canary

]# kubectl get pods -w 
NAME                           READY   STATUS    RESTARTS   AGE
myapp-deploy-559ff5c66-2sqtc   1/1     Running   0          7m54s
myapp-deploy-559ff5c66-gmgfn   1/1     Running   0          7m57s

myapp-deploy-65fb6c8459-ds9fg   0/1     Pending   0          0s
myapp-deploy-65fb6c8459-ds9fg   0/1     Pending   0          0s
myapp-deploy-65fb6c8459-ds9fg   0/1     ContainerCreating   0          0s
myapp-deploy-65fb6c8459-ds9fg   1/1     Running             0          1s
myapp-deploy-559ff5c66-2sqtc    1/1     Terminating         0          10m
myapp-deploy-65fb6c8459-q6kn9   0/1     Pending             0          0s
myapp-deploy-65fb6c8459-q6kn9   0/1     Pending             0          0s
myapp-deploy-65fb6c8459-q6kn9   0/1     ContainerCreating   0          0s
myapp-deploy-559ff5c66-2sqtc    0/1     Terminating         0          10m
myapp-deploy-65fb6c8459-q6kn9   1/1     Running             0          2s
myapp-deploy-559ff5c66-gmgfn    1/1     Terminating         0          10m
myapp-deploy-559ff5c66-gmgfn    0/1     Terminating         0          10m
myapp-deploy-559ff5c66-gmgfn    0/1     Terminating         0          10m
myapp-deploy-559ff5c66-gmgfn    0/1     Terminating         0          10m
myapp-deploy-559ff5c66-2sqtc    0/1     Terminating         0          10m
myapp-deploy-559ff5c66-2sqtc    0/1     Terminating         0          10m

11）查看滚动后状态与历史

]# kubectl rollout status deployment/myapp-deploy 
deployment "myapp-deploy" successfully rolled out

]# kubectl rollout history deployment
deployment.apps/myapp-deploy 
REVISION  CHANGE-CAUSE
2         <none>
3         <none>

]# kubectl get rs -o wide
NAME                      DESIRED   CURRENT   READY   AGE   CONTAINERS   IMAGES                 SELECTOR
myapp-deploy-559ff5c66    0         0         0       14m   myapp        ikubernetes/myapp:v2   app=myapp,pod-template-hash=559ff5c66,release=canary
myapp-deploy-65fb6c8459   2         2         2       32m   myapp        ikubernetes/myapp:v1   app=myapp,pod-template-hash=65fb6c8459,release=canary

12）访问回滚后的Pod资源

]# kubectl get pods -o wide 
NAME                            READY   STATUS    RESTARTS   AGE   IP            NODE    NOMINATED NODE   READINESS GATES
myapp-deploy-65fb6c8459-djg6k   1/1     Running   0          54s   10.244.2.12   node2   <none>           <none>
myapp-deploy-65fb6c8459-jp7hc   1/1     Running   0          53s   10.244.1.36   node1   <none>           <none>

]# curl 10.244.2.12
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

]# curl 10.244.1.36
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

13）暂停与恢复Deployment的回滚

]# kubectl rollout undo deployment/myapp-deploy --to-revision=4
deployment.apps/myapp-deploy rolled back

]# kubectl rollout pause deployment/myapp-deploy
deployment.apps/myapp-deploy paused

]# kubectl rollout resume deployment/myapp-deploy 
deployment.apps/myapp-deploy resumed

Deployment的清理策略：
　　可以通过设置.spec.revisonHistoryLimit项来指定Deployment控制器最多保留多少revision历史记录，默认Deployment控制器会保留所有的revision版本；如果该项设置为0，则Deployment控制器就不允许做回滚操作了。