website/content/cn/docs/tasks/run-application/run-stateless-application-deployment.md

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使用Deployment运行一个无状态应用	templates/tutorial

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本文介绍通过Kubernetes Deployment对象如何去运行一个应用.

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• 创建一个nginx deployment.
• 使用kubectl列举关于deployment信息.
• 更新deployment.

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创建和探究一个nginx deployment

你可以通过创建一个Kubernetes Deployment对象来运行一个应用, 可以在一个YAML文件中描述Deployment. 例如, 下面这个YAML文件描述了一个运行nginx:1.7.9 Docker镜像的Deployment:

{{< code file="deployment.yaml" >}}

1. 通过YAML文件创建一个Deployment:

   kubectl create -f https://k8s.io/docs/tasks/run-application/deployment.yaml
   

2. 展示Deployment相关信息:

   kubectl describe deployment nginx-deployment
   
    user@computer:~/website$ kubectl describe deployment nginx-deployment
    Name:     nginx-deployment
    Namespace:    default
    CreationTimestamp:  Tue, 30 Aug 2016 18:11:37 -0700
    Labels:     app=nginx
    Annotations:    deployment.kubernetes.io/revision=1
    Selector:   app=nginx
    Replicas:   2 desired | 2 updated | 2 total | 2 available | 0 unavailable
    StrategyType:   RollingUpdate
    MinReadySeconds:  0
    RollingUpdateStrategy:  1 max unavailable, 1 max surge
    Pod Template:
      Labels:       app=nginx
      Containers:
       nginx:
        Image:              nginx:1.7.9
        Port:               80/TCP
        Environment:        <none>
        Mounts:             <none>
      Volumes:              <none>
    Conditions:
      Type          Status  Reason
      ----          ------  ------
      Available     True    MinimumReplicasAvailable
      Progressing   True    NewReplicaSetAvailable
    OldReplicaSets:   <none>
    NewReplicaSet:    nginx-deployment-1771418926 (2/2 replicas created)
    No events.
   

3. 列出deployment创建的pods:

   kubectl get pods -l app=nginx
   
    NAME                                READY     STATUS    RESTARTS   AGE
    nginx-deployment-1771418926-7o5ns   1/1       Running   0          16h
    nginx-deployment-1771418926-r18az   1/1       Running   0          16h
   

4. 展示某一个pod信息:

   kubectl describe pod <pod-name>
   

   该处 <pod-name> 指某一pod的名称.

更新deployment

你可以通过更新一个新的YAML文件来更新deployment. 下面的YAML文件指定该deployment镜像更新为nginx 1.8.

{{< code file="deployment-update.yaml" >}}

1. 应用新的YAML:

   kubectl apply -f https://k8s.io/docs/tutorials/stateless-application/deployment-update.yaml
   

2. 查看该deployment创建的pods以新的名称同时删除旧的pods:

   kubectl get pods -l app=nginx
   

通过增加副本数来弹缩应用

你可以通过应用新的YAML文件来增加Deployment中pods的数量. 该YAML文件将replicas设置为4, 指定该Deployment应有4个pods:

{{< code file="deployment-scale.yaml" >}}

1. 应用新的YAML文件:

   kubectl apply -f https://k8s.io/docs/tutorials/stateless-application/deployment-scale.yaml
   

2. 验证Deployment有4个pods:

   kubectl get pods -l app=nginx
   

   输出的结果类似于:

    NAME                               READY     STATUS    RESTARTS   AGE
    nginx-deployment-148880595-4zdqq   1/1       Running   0          25s
    nginx-deployment-148880595-6zgi1   1/1       Running   0          25s
    nginx-deployment-148880595-fxcez   1/1       Running   0          2m
    nginx-deployment-148880595-rwovn   1/1       Running   0          2m
   

删除deployment

通过名称删除deployment:

kubectl delete deployment nginx-deployment

ReplicationControllers -- 旧的方式

创建一个多副本应用首选方法是使用Deployment,反过来使用ReplicaSet. 在Deployment和ReplicaSet加入到Kubernetes之前, 多副本应用通过ReplicationController来配置.

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• 了解更多 Deployment objects.

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