03.kubernetes笔记 Pod控制器(二) Deployment

Bigyong

Deployment简介

Deployment 为 Pod 和 ReplicaSet 提供了一个声明式定义 (declarative) 方法,用来替代以前的ReplicationController 来方便的管理应用。典型的应用场景包括;定义 Deployment 来创建 Pod 和 ReplicaSet

  1. 滚动升级和回滚应用
  2. 扩容和缩容
  3. 暂停和继续 Deploymen

Deployment 无状态服务最常用的Pod管理器
Deployment 实际是管理ReplicaSet Deployment默认会保存10个ReplicaSet历史版本
Deployment 会把ReplicaSet之前个版本的副本数修改为0

Deployment 字段格式

apiVersion: apps/v1 #API群组及版本
kind: Deployment #资源类型特有标识
metadata:
  name <string>  #资源名称,在作用域中要唯一
  namespace <string>  #名称空间;Deployment隶属名称空间级别
spec:  
  minReadySeconds <integer> #Pod就绪后多少秒内任一容器无crash方可视为“就绪”
  replicas <integer>  #期望的Pod副本数,默认为1
  selector <object> #标签选择器,必须匹配template字段中Pod模板中的标签
  template <object> #Pod模板对象
  revisionHistoryLimit <integer> #滚动更新历史记录数量,默认为10
  strategy <0bject> #滚动更新策略
    type <string>  #滚动更新类型,可用值有Recreate和Rollingupdate; Recreate 重建更新一次性删除所有Pod;Rollingupdate  滚动更新默认策略
    rollingUpdate <0bject> #滚动更新参数,专用于RollingUpdate类型
    maxSurge <string> #更新期间可比期望的Pod数量多出的数量或比例
    maxUnavailable <string> #更新期间可比期望的Pod数量缺少的数量或比例
  progressDeadlineSeconds <integer> # 滚动更新故障超时时长,默认为600秒
  paused <boolean> #是否暂停部暑过程

示例1: 创建Deployment控制器 Pod副本数为4

[root@k8s-master PodControl]# cat deployment-demo.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: deployment-demo
spec:
  replicas: 4  #副本数来4
  selector:
    matchLabels:
      app: demoapp
      release: stable
  template:
    metadata:
      labels :
        app: demoapp
        release: stable
    spec:
      containers:
      - name: demoapp
        image: ikubernetes/demoapp:${VERSION}
        ports:
        - containerPort: 80
          name: http

[root@k8s-master PodControl]# kubectl apply -f deployment-demo.yaml 
deployment.apps/deployment-demo created

[root@k8s-master PodControl]# VERSION=v1.0 envsubst < deployment-demo.yaml |kubectl apply -f  -
deployment.apps/deployment-demo created

[root@k8s-master PodControl]# kubectl get deployment
NAME              READY   UP-TO-DATE   AVAILABLE   AGE
deployment-demo   4/4     4            4           54s

#可以看到创建了同名的rs deployment实际管理的是rs而不是Pod
#名称中的 fb544c5d8 是通过配置文的生成的hash值,当检查到配置文件hash值变化就会启到更新

[root@k8s-master PodControl]# kubectl get rs
NAME                        DESIRED   CURRENT   READY   AGE
deployment-demo-fb544c5d8   4         4         4       56s    

[root@k8s-master PodControl]# kubectl get pod
NAME                              READY   STATUS    RESTARTS   AGE
deployment-demo-fb544c5d8-kz8fn   1/1     Running   0          58s
deployment-demo-fb544c5d8-p6q4v   1/1     Running   0          58s
deployment-demo-fb544c5d8-ttjmt   1/1     Running   0          58s
deployment-demo-fb544c5d8-x2lqw   1/1     Running   0          58s


[root@k8s-master PodControl]# kubectl describe deployment/deployment-demo
Name:                   deployment-demo
Namespace:              default
CreationTimestamp:      Mon, 16 Aug 2021 16:17:28 +0800
Labels:                 <none>
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=demoapp,release=stable
Replicas:               4 desired | 4 updated | 4 total | 4 available | 0 unavailable
StrategyType:           RollingUpdate   #可以看到默认的更新策略
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge  #默认的更新比例为 25%

更新deployment rollout命令查看状态

[root@k8s-master PodControl]# kubectl rollout --help  #查看张帮助选项
Manage the rollout of a resource.
  
 Valid resource types include:  #可以更新的资源类型

  *  deployments
  *  daemonsets
  *  statefulsets

Examples:
  # Rollback to the previous deployment
  kubectl rollout undo deployment/abc
  
  # Check the rollout status of a daemonset
  kubectl rollout status daemonset/foo

Available Commands:
  history     View rollout history   #历史记录
  pause       Mark the provided resource as paused  #暂停
  restart     Restart a resource  #重启
  resume      Resume a paused resource  #恢复暂时资源
  status      Show the status of the rollout  #查看资源更新状态
  undo        Undo a previous rollout  #版本回退


[root@k8s-master PodControl]# VERSION=v1.1 envsubst < deployment-demo.yaml |kubectl apply -f -
deployment.apps/deployment-demo configured


[root@k8s-master PodControl]# kubectl rollout status deployment/deployment-demo
deployment "deployment-demo" successfully rolled out   #查看更新状态成功


[root@k8s-master PodControl]# kubectl get deployment
NAME              READY   UP-TO-DATE   AVAILABLE   AGE
deployment-demo   4/4     4            4           2

[root@k8s-master PodControl]# kubectl get rs
NAME                         DESIRED   CURRENT   READY   AGE
deployment-demo-867c7d9d55   4         4         4       6m5s
deployment-demo-fb544c5d8    0         0         0       25m   #旧版本副本数为0

[root@k8s-master PodControl]# kubectl get pod -o wide
NAME                               READY   STATUS    RESTARTS   AGE     IP             NODE        NOMINATED NODE   READINESS GATES
deployment-demo-867c7d9d55-d6xvt   1/1     Running   0          6m55s   10.244.1.229   k8s-node1   <none>           <none>
deployment-demo-867c7d9d55-l65z9   1/1     Running   0          6m47s   10.244.2.209   k8s-node2   <none>           <none>
deployment-demo-867c7d9d55-vhs6t   1/1     Running   0          6m55s   10.244.3.56    k8s-node3   <none>           <none>
deployment-demo-867c7d9d55-zc8dm   1/1     Running   0          6m43s   10.244.1.230   k8s-node1   <none>           <none>
[root@k8s-master PodControl]# curl 10.244.1.229
iKubernetes demoapp v1.1 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-867c7d9d55-d6xvt, ServerIP: 10.244.1.229!
  • 在次更新使用 kubectl rollout status查看更新状态状

    [root@k8s-master PodControl]# VERSION=v1.2 envsubst < deployment-demo.yaml |kubectl apply -f - && kubectl rollout status deployment/deployment-demo
    deployment.apps/deployment-demo configured
    Waiting for deployment spec update to be observed...
    Waiting for deployment "deployment-demo" rollout to finish: 1 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 1 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 1 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 2 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 2 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 2 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 3 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 3 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 3 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 3 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 3 out of 4 new replicas have been updated...
    Waiting for deployment "deployment-demo" rollout to finish: 1 old replicas are pending termination...
    Waiting for deployment "deployment-demo" rollout to finish: 1 old replicas are pending termination...
    Waiting for deployment "deployment-demo" rollout to finish: 1 old replicas are pending termination...
    Waiting for deployment "deployment-demo" rollout to finish: 3 of 4 updated replicas are available...
    deployment "deployment-demo" successfully rolled out
    
    [root@k8s-master PodControl]# kubectl get rs    #可以看到rs又多了一个版本副本数为0
    NAME                         DESIRED   CURRENT   READY   AGE
    deployment-demo-77d46c4794   4         4         4       2m25s
    deployment-demo-867c7d9d55   0         0         0       10m
    deployment-demo-fb544c5d8    0         0         0       29m
    
    #验证
    [root@k8s-master PodControl]# kubectl get pod -o wide
    NAME                               READY   STATUS    RESTARTS   AGE     IP             NODE        NOMINATED NODE   READINESS GATES
    deployment-demo-77d46c4794-fbt5l   1/1     Running   0          2m44s   10.244.2.210   k8s-node2   <none>           <none>
    deployment-demo-77d46c4794-kdvn2   1/1     Running   0          3m20s   10.244.1.231   k8s-node1   <none>           <none>
    deployment-demo-77d46c4794-lcm28   1/1     Running   0          3m20s   10.244.3.57    k8s-node3   <none>           <none>
    deployment-demo-77d46c4794-x52sh   1/1     Running   0          2m40s   10.244.1.232   k8s-node1   <none>           <none>
    [root@k8s-master PodControl]# curl 10.244.2.210
    iKubernetes demoapp v1.2 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-77d46c4794-fbt5l, ServerIP: 10.244.2.210!

    示例2: Deployment版本回滚

  • 回滚 回滚时可以指定回滚版本,默认回滚到前一个版本,
  • 这里需要注意的是,假设当前版本为A,前一个版本为B,回滚后当前版本A变成前一版本,再次回滚后A从前一版本回滚到最新版本,所以如果不指定版本,回滚只在最后两个版本间滚动
[root@k8s-master PodControl]# kubectl rollout history deployment/deployment-demo
deployment.apps/deployment-demo 
REVISION  CHANGE-CAUSE
1         <none>   #更新过3次 3个不同的版本  回滚时可以
2         <none>
3         <none>

[root@k8s-master PodControl]# kubectl rollout undo deployment/deployment-demo
deployment.apps/deployment-demo rolled back
[root@k8s-master PodControl]# kubectl rollout history deployment/deployment-demo
deployment.apps/deployment-demo 
REVISION  CHANGE-CAUSE
1         <none>
3         <none>
4         <none>   #版本2变成4为最新版本 序列号只会递增

[root@k8s-master PodControl]# kubectl rollout undo --dry-run=server deployment/deployment-demo  #不执行测试是否能成功
deployment.apps/deployment-demo rolled back (server dry run)

[root@k8s-master PodControl]# kubectl rollout undo deployment/deployment-demo  --to-revision=1  #回滚到指定版本
deployment.apps/deployment-demo rolled back
[root@k8s-master PodControl]# kubectl rollout history deployment/deployment-demo
deployment.apps/deployment-demo 
REVISION  CHANGE-CAUSE
3         <none>
4         <none>
5         <none>


[root@k8s-master PodControl]# kubectl get rs
NAME                         DESIRED   CURRENT   READY   AGE
deployment-demo-77d46c4794   0         0         0       17m
deployment-demo-867c7d9d55   0         0         0       26m
deployment-demo-fb544c5d8    4         4         4       45m   #只有最开始的rs副本数为4 其它都为0

[root@k8s-master PodControl]# kubectl get pod -o wide
NAME                               READY   STATUS        RESTARTS   AGE     IP             NODE        NOMINATED NODE   READINESS GATES
deployment-demo-867c7d9d55-b65cm   0/1     Terminating   0          4m2s    10.244.1.234   k8s-node1   <none>           <none>
deployment-demo-867c7d9d55-pv8fp   1/1     Terminating   0          4m10s   10.244.3.58    k8s-node3   <none>           <none>
deployment-demo-867c7d9d55-tnhsg   1/1     Terminating   0          4m14s   10.244.1.233   k8s-node1   <none>           <none>
deployment-demo-867c7d9d55-wcvl7   1/1     Terminating   0          4m14s   10.244.2.211   k8s-node2   <none>           <none>
deployment-demo-fb544c5d8-5f9lp    1/1     Running       0          32s     10.244.1.235   k8s-node1   <none>           <none>
deployment-demo-fb544c5d8-d5lr9    1/1     Running       0          22s     10.244.1.236   k8s-node1   <none>           <none>
deployment-demo-fb544c5d8-lj5gt    1/1     Running       0          29s     10.244.3.59    k8s-node3   <none>           <none>
deployment-demo-fb544c5d8-t9swj    1/1     Running       0          32s     10.244.2.212   k8s-node2   <none>           <none>



[root@k8s-master PodControl]# curl 10.244.2.212  #测试回滚版本
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-t9swj, ServerIP: 10.244.2.212!

示例3: 使用 pause 模拟金丝雀发布


#指定回滚版本或更新版本后,马上暂停,这样只回滚或更新第一批Pod,模拟金丝雀发布让 用一小部分流量测试服务是否正常
[root@k8s-master PodControl]# kubectl rollout undo deployment/deployment-demo  --to-revision=3 && kubectl rollout pause deployment/deployment-demo  
deployment.apps/deployment-demo rolled back
deployment.apps/deployment-demo paused

#只更新了第一批就阻塞住了
[root@k8s-master PodControl]# kubectl rollout status  deployment/deployment-demo
Waiting for deployment "deployment-demo" rollout to finish: 2 out of 4 new replicas have been updated...

[root@k8s-master PodControl]# kubectl get rs
NAME                         DESIRED   CURRENT   READY   AGE
deployment-demo-58c8475bcc   0         0         0       5m42s
deployment-demo-77d46c4794   2         2         1       36m
deployment-demo-867c7d9d55   0         0         0       44m
deployment-demo-fb544c5d8    3         3         3       63m


[root@k8s-master ~]# kubectl get svc
NAME             TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
demoapp-deploy   ClusterIP   10.107.174.169   <none>        80/TCP    18s

#让流量

[root@k8s-master ~]# while true; do curl --connect-timeout 1 10.107.174.169; sleep .2;done   #新旧版本同时存在
iKubernetes demoapp v1.2 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-77d46c4794-fhz4l, ServerIP: 10.244.1.238!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-lj5gt, ServerIP: 10.244.3.59!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-t9swj, ServerIP: 10.244.2.212!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-5f9lp, ServerIP: 10.244.1.235!
iKubernetes demoapp v1.2 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-77d46c4794-kmrhn, ServerIP: 10.244.3.60!
iKubernetes demoapp v1.2 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-77d46c4794-fhz4l, ServerIP: 10.244.1.238!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-lj5gt, ServerIP: 10.244.3.59!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-t9swj, ServerIP: 10.244.2.212!
iKubernetes demoapp v1.0 !! ClientIP: 10.244.0.0, ServerName: deployment-demo-fb544c5d8-5f9lp, ServerIP: 10.244.1.235!

示例4: 修改Deployment滚动更新策略

  • 更新策略需要根据自己的实际情况配置 比如流量较大,要保证一定的Pod数量,那就要保证更新时Pod的数量不能少
  • 如果系统资源比较紧张,那更新时Pod的数量要保持不变,以免增大对系统资源的负担
[root@k8s-master PodControl]# cat deployment-demo-with-strategy.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: deployment-demo-with-strategy
spec:
  replicas: 4
  selector:
    matchLabels:
      app: demoapp
      release: stable
      strategy: ture
  template:
    metadata:
      labels :
        app: demoapp
        release: stable
        strategy: ture
    spec:
      containers:
      - name: demoapp
        image: ikubernetes/demoapp:${VERSION}
        ports:
        - containerPort: 80
          name: http
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 0   #总的Pod数量不能多
      maxUnavailable: 1   #总的数量可以减少1个  先减在加  在系统资源紧缺的时候使用


[root@k8s-master PodControl]# VERSION=v1.0 envsubst < deployment-demo-with-strategy.yaml |kubectl apply -f -
deployment.apps/deployment-demo-with-strategy created

[root@k8s-master PodControl]# kubectl get deployment
NAME                            READY   UP-TO-DATE   AVAILABLE   AGE
deployment-demo                 5/4     2            5           90m
deployment-demo-with-strategy   4/4     4            4           49s

[root@k8s-master PodControl]# kubectl describe deployment/deployment-demo-with-strategy
Name:                   deployment-demo-with-strategy
Namespace:              default
CreationTimestamp:      Mon, 16 Aug 2021 17:46:52 +0800
Labels:                 <none>
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=demoapp,release=stable,strategy=ture
Replicas:               4 desired | 4 updated | 4 total | 4 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  1 max unavailable, 0 max surge   #更新策略生效

[root@k8s-master PodControl]# kubectl get deployment
NAME                            READY   UP-TO-DATE   AVAILABLE   AGE
deployment-demo                 5/4     2            5           93m
deployment-demo-with-strategy   4/4     4            4           3m58s

[root@k8s-master PodControl]# kubectl get pod
NAME                                             READY   STATUS    RESTARTS   AGE
deployment-demo-77d46c4794-fhz4l                 1/1     Running   0          26m
deployment-demo-77d46c4794-kmrhn                 1/1     Running   0          26m
deployment-demo-fb544c5d8-5f9lp                  1/1     Running   0          46m
deployment-demo-fb544c5d8-lj5gt                  1/1     Running   0          46m
deployment-demo-fb544c5d8-t9swj                  1/1     Running   0          46m
deployment-demo-with-strategy-57b96bdc87-8mjzw   1/1     Running   0          39s
deployment-demo-with-strategy-57b96bdc87-k6rxx   1/1     Running   0          38s
deployment-demo-with-strategy-57b96bdc87-v4tdj   1/1     Running   0          38s
deployment-demo-with-strategy-57b96bdc87-zdvcp   1/1     Running   0          38s

#查看更新状态 先减后增
[root@k8s-master PodControl]# VERSION=v1.1 envsubst < deployment-demo-with-strategy.yaml |kubectl apply -f - && kubectl rollout status deployment/deployment-demo-with-strategy
deployment.apps/deployment-demo-with-strategy configured
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 0 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 0 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 1 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 1 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 1 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 2 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 2 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 2 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 3 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 3 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 3 out of 4 new replicas have been updated...
Waiting for deployment "deployment-demo-with-strategy" rollout to finish: 3 of 4 updated replicas are available...
deployment "deployment-demo-with-strategy" successfully rolled out
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