145 lines
4.3 KiB
Markdown
145 lines
4.3 KiB
Markdown
---
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title: 使用Deployment运行一个无状态应用
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content_template: templates/tutorial
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---
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{{% capture overview %}}
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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.
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* 使用kubectl列举关于deployment信息.
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* 更新deployment.
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{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
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## 创建和探究一个nginx deployment
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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:
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{{< code file="deployment.yaml" >}}
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1. 通过YAML文件创建一个Deployment:
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kubectl create -f https://k8s.io/docs/tasks/run-application/deployment.yaml
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1. 展示Deployment相关信息:
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kubectl describe deployment nginx-deployment
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user@computer:~/website$ kubectl describe deployment nginx-deployment
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Name: nginx-deployment
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Namespace: default
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CreationTimestamp: Tue, 30 Aug 2016 18:11:37 -0700
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Labels: app=nginx
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Annotations: deployment.kubernetes.io/revision=1
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Selector: app=nginx
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Replicas: 2 desired | 2 updated | 2 total | 2 available | 0 unavailable
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StrategyType: RollingUpdate
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MinReadySeconds: 0
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RollingUpdateStrategy: 1 max unavailable, 1 max surge
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Pod Template:
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Labels: app=nginx
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Containers:
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nginx:
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Image: nginx:1.7.9
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Port: 80/TCP
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Environment: <none>
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Mounts: <none>
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Volumes: <none>
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Conditions:
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Type Status Reason
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---- ------ ------
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Available True MinimumReplicasAvailable
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Progressing True NewReplicaSetAvailable
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OldReplicaSets: <none>
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NewReplicaSet: nginx-deployment-1771418926 (2/2 replicas created)
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No events.
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1. 列出deployment创建的pods:
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kubectl get pods -l app=nginx
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NAME READY STATUS RESTARTS AGE
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nginx-deployment-1771418926-7o5ns 1/1 Running 0 16h
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nginx-deployment-1771418926-r18az 1/1 Running 0 16h
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1. 展示某一个pod信息:
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kubectl describe pod <pod-name>
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该处 `<pod-name>` 指某一pod的名称.
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## 更新deployment
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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.
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{{< code file="deployment-update.yaml" >}}
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1. 应用新的YAML:
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kubectl apply -f https://k8s.io/docs/tutorials/stateless-application/deployment-update.yaml
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1. 查看该deployment创建的pods以新的名称同时删除旧的pods:
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kubectl get pods -l app=nginx
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## 通过增加副本数来弹缩应用
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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:
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{{< code file="deployment-scale.yaml" >}}
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1. 应用新的YAML文件:
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kubectl apply -f https://k8s.io/docs/tutorials/stateless-application/deployment-scale.yaml
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1. 验证Deployment有4个pods:
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kubectl get pods -l app=nginx
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输出的结果类似于:
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NAME READY STATUS RESTARTS AGE
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nginx-deployment-148880595-4zdqq 1/1 Running 0 25s
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nginx-deployment-148880595-6zgi1 1/1 Running 0 25s
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nginx-deployment-148880595-fxcez 1/1 Running 0 2m
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nginx-deployment-148880595-rwovn 1/1 Running 0 2m
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## 删除deployment
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通过名称删除deployment:
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kubectl delete deployment nginx-deployment
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## ReplicationControllers -- 旧的方式
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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](/docs/concepts/workloads/controllers/replicationcontroller/)来配置.
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{{% /capture %}}
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{{% capture whatsnext %}}
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* 了解更多 [Deployment objects](/docs/concepts/workloads/controllers/deployment/).
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{{% /capture %}}
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