Deployment 更新/回滚
This commit is contained in:
huanqing.shao
@ -19,6 +19,8 @@ Kuboard 是一款基于 Kubernetes 的微服务管理界面。
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提供最新版本的 [Kubernetes (K8S) 安装手册](https://www.kuboard.cn/install/install-k8s.html)，协同创作，在线答疑，持续更新。
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点击此处，查看 [Kuboard 安装文档](https://kuboard.cn/install/install-dashboard.html)
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[点击查看在线文档](https://www.kuboard.cn/#from_github)
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@ -7,14 +7,213 @@ description: 本文描述了如何在 Kubernetes 中回滚 Deployment
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[返回 Deployment](./#deployment-概述)
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某些情况下，您可能想要回滚（rollback）Deployment，例如：Deployment 不稳定（可能是不断地崩溃）。默认情况下，kubernetes 将保存 Deployment 的所有更新（rollout）历史。您可以设定 revision history limit 来确定保存的历史版本数量。
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::: tip
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当且仅当 Deployment 的 `.spec.template` 字段被修改时（例如，您修改了容器的镜像），kubernetes 将为其创建一个 Deployment revision（版本）。Deployment 的其他更新（例如：修改 `.spec.replicas` 字段）将不会创建新的 Deployment reviesion（版本）。
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:::
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<el-tabs type="border-card">
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<el-tab-pane label="使用 kubectl 更新 Deployment">
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正在撰写中
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<h2>模拟更新错误</h2>
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* 假设您在更新 Deployment 的时候，犯了一个拼写错误，将 `nginx:1.9.1` 写成了 `nginx:1.91`
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``` sh
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kubectl set image deployment.v1.apps/nginx-deployment nginx=nginx:1.91 --record=true
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```
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输出结果如下所示：
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```
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deployment.apps/nginx-deployment image updated
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```
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* 该更新将卡住，您可以执行命令 `kubectl rollout status deployment.v1.apps/nginx-deployment` 检查其状态，输出结果如下所示：
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```
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Waiting for rollout to finish: 1 out of 3 new replicas have been updated...
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```
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* 执行命令 `kubectl get rs` 您将看到两个旧的 ReplicaSet（nginx-deployment-1564180365 and nginx-deployment-2035384211）和一个新的 ReplicaSet (nginx-deployment-3066724191) 。如下所示：
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```
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NAME DESIRED CURRENT READY AGE
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nginx-deployment-1564180365 3 3 3 25s
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nginx-deployment-2035384211 0 0 0 36s
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nginx-deployment-3066724191 1 1 0 6s
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```
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* 执行命令 `kubectl get pods`，您将看到 1 个由新 ReplicaSet 创建的 Pod 卡在抓取 image 的死循环里：
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```
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NAME READY STATUS RESTARTS AGE
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nginx-deployment-1564180365-70iae 1/1 Running 0 25s
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nginx-deployment-1564180365-jbqqo 1/1 Running 0 25s
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nginx-deployment-1564180365-hysrc 1/1 Running 0 25s
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nginx-deployment-3066724191-08mng 0/1 ImagePullBackOff 0 6s
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```
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::: tip
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Deployment Controller 将自动停止有问题的更新（rollout），不会继续 scale up 新的 ReplicaSet。maxUnavailable 参数指定了最多会有几个 Pod 副本卡住，该参数的默认值是 25%。
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:::
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* 执行命令 `kubectl describe deployment` 查看 Deployment 的详情，输出结果如下所示：
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```
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Name: nginx-deployment
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Namespace: default
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CreationTimestamp: Tue, 15 Mar 2016 14:48:04 -0700
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Labels: app=nginx
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Selector: app=nginx
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Replicas: 3 desired | 1 updated | 4 total | 3 available | 1 unavailable
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StrategyType: RollingUpdate
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MinReadySeconds: 0
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RollingUpdateStrategy: 25% max unavailable, 25% 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:1.91
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Port: 80/TCP
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Host Port: 0/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 ReplicaSetUpdated
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OldReplicaSets: nginx-deployment-1564180365 (3/3 replicas created)
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NewReplicaSet: nginx-deployment-3066724191 (1/1 replicas created)
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Events:
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FirstSeen LastSeen Count From SubobjectPath Type Reason Message
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--------- -------- ----- ---- ------------- -------- ------ -------
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1m 1m 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-2035384211 to 3
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22s 22s 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-1564180365 to 1
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22s 22s 1 {deployment-controller } Normal ScalingReplicaSet Scaled down replica set nginx-deployment-2035384211 to 2
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22s 22s 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-1564180365 to 2
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21s 21s 1 {deployment-controller } Normal ScalingReplicaSet Scaled down replica set nginx-deployment-2035384211 to 1
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21s 21s 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-1564180365 to 3
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13s 13s 1 {deployment-controller } Normal ScalingReplicaSet Scaled down replica set nginx-deployment-2035384211 to 0
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13s 13s 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-3066724191 to 1
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```
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为了修复这个问题，您需要将其回滚到之前的一个稳定版本。
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<h2>检查 Deployment 的更新历史</h2>
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1. 执行命令 `kubectl rollout history deployment.v1.apps/nginx-deployment` 检查 Deployment 的历史版本，输出结果如下所示：
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```
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deployments "nginx-deployment"
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REVISION CHANGE-CAUSE
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1 kubectl apply --filename=https://k8s.io/examples/controllers/nginx-deployment.yaml --record=true
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2 kubectl set image deployment.v1.apps/nginx-deployment nginx=nginx:1.9.1 --record=true
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3 kubectl set image deployment.v1.apps/nginx-deployment nginx=nginx:1.91 --record=true
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```
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**CHANGE-CAUSE** 是该 revision（版本）创建时从 Deployment 的 annotation `kubernetes.io/change-cause` 拷贝而来。
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您可以通过如下方式制定 **CHANGE-CAUSE** 信息：
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* 为 Deployment 增加注解，`kubectl annotate deployment.v1.apps/nginx-deployment kubernetes.io/change-cause="image updated to 1.9.1"`
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* 执行 kubectl apply 命令时，增加 `--record` 选项
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* 手动编辑 Deployment 的 `.metadata.annotation` 信息
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2. 执行命令 `kubectl rollout history deployment.v1.apps/nginx-deployment --revision=2`，查看 revision（版本）的详细信息，输出结果如下所示：
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```
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deployments "nginx-deployment" revision 2
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Labels: app=nginx
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pod-template-hash=1159050644
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Annotations: kubernetes.io/change-cause=kubectl set image deployment.v1.apps/nginx-deployment nginx=nginx:1.9.1 --record=true
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Containers:
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nginx:
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Image: nginx:1.9.1
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Port: 80/TCP
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QoS Tier:
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cpu: BestEffort
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memory: BestEffort
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Environment Variables: <none>
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No volumes.
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```
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<h2>回滚到前一个 revision（版本）</h2>
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下面的步骤可将 Deployment 从当前版本回滚到前一个版本（version 2）
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1. 执行命令 `kubectl rollout undo deployment.v1.apps/nginx-deployment` 将当前版本回滚到前一个版本，输出结果如下所示：
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```
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deployment.apps/nginx-deployment
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```
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或者，您也可以使用 `--to-revision` 选项回滚到前面的某一个指定版本，执行如下命令：
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```sh
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kubectl rollout undo deployment.v1.apps/nginx-deployment --to-revision=2
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```
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输出结果如下：
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```
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deployment.apps/nginx-deployment
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```
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更详细的信息，请参考 [kubectl rollout](https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#rollout)
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此时，Deployment 已经被回滚到前一个稳定版本。您可以看到 Deployment Controller 为该 Deployment 产生了 DeploymentRollback event。
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2. 执行命令 `kubectl get deployment nginx-deployment`，检查该回滚是否成功，Deployment 是否按预期的运行，输出结果如下：
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```
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NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
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nginx-deployment 3 3 3 3 30m
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```
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3. 执行命令 `kubectl describe deployment nginx-deployment` 查看 Deployment 的详情，输出结果如下：
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```
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Name: nginx-deployment
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Namespace: default
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CreationTimestamp: Sun, 02 Sep 2018 18:17:55 -0500
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Labels: app=nginx
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Annotations: deployment.kubernetes.io/revision=4
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kubernetes.io/change-cause=kubectl set image deployment.v1.apps/nginx-deployment nginx=nginx:1.9.1 --record=true
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Selector: app=nginx
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Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
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StrategyType: RollingUpdate
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MinReadySeconds: 0
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RollingUpdateStrategy: 25% max unavailable, 25% 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:1.9.1
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Port: 80/TCP
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Host Port: 0/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-c4747d96c (3/3 replicas created)
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Events:
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Type Reason Age From Message
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---- ------ ---- ---- -------
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Normal ScalingReplicaSet 12m deployment-controller Scaled up replica set nginx-deployment-75675f5897 to 3
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Normal ScalingReplicaSet 11m deployment-controller Scaled up replica set nginx-deployment-c4747d96c to 1
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Normal ScalingReplicaSet 11m deployment-controller Scaled down replica set nginx-deployment-75675f5897 to 2
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Normal ScalingReplicaSet 11m deployment-controller Scaled up replica set nginx-deployment-c4747d96c to 2
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Normal ScalingReplicaSet 11m deployment-controller Scaled down replica set nginx-deployment-75675f5897 to 1
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Normal ScalingReplicaSet 11m deployment-controller Scaled up replica set nginx-deployment-c4747d96c to 3
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Normal ScalingReplicaSet 11m deployment-controller Scaled down replica set nginx-deployment-75675f5897 to 0
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Normal ScalingReplicaSet 11m deployment-controller Scaled up replica set nginx-deployment-595696685f to 1
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Normal DeploymentRollback 15s deployment-controller Rolled back deployment "nginx-deployment" to revision 2
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Normal ScalingReplicaSet 15s deployment-controller Scaled down replica set nginx-deployment-595696685f to 0
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```
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</el-tab-pane>
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<el-tab-pane label="使用 Kuboard 更新 Deployment">
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正在撰写中
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</el-tab-pane>
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@ -7,11 +7,135 @@ description: 本文描述了如何在 Kubernetes 中更新 Deployment
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[返回 Deployment](./#deployment-概述)
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## 执行更新
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::: tip
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当且仅当 Deployment 的 Pod template（`.spec.template`）字段中的内容发生变更时（例如标签、容器的镜像被改变），Deployment 的发布更新（rollout）将被触发。Deployment 中其他字段的变化（例如修改 .spec.replicas 字段）将不会触发 Deployment 的发布更新（rollout）
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:::
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本文提供了两种途径对 Deployment 执行发布更新（rollout）：
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* 使用 kubectl 更新 Deployment
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* 使用 Kuboard 更新 Deployment
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<el-tabs type="border-card">
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<el-tab-pane label="使用 kubectl 更新 Deployment">
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正在撰写中
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**使用下述步骤更新您的 Deployment**
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1. 执行以下命令，将容器镜像从 nginx:1.7.9 更新到 nginx:1.9.1
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```sh
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kubectl --record deployment.apps/nginx-deployment set image deployment.v1.apps/nginx-deployment nginx=nginx:1.9.1
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```
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输出结果如下所示：
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```
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deployment.apps/nginx-deployment image updated
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```
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或者，您可以 `edit` 该 Deployment，并将 `.spec.template.spec.containers[0].image` 从 `nginx:1.7.9` 修改为 `nginx:1.9.1`
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```sh
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kubectl edit deployment.v1.apps/nginx-deployment
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```
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输出结果如下所示
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```
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deployment.apps/nginx-deployment edited
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```
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2. 查看发布更新（rollout）的状态，执行命令：
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```sh
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kubectl rollout status deployment.v1.apps/nginx-deployment
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```
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输出结果如下所示：
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```
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Waiting for rollout to finish: 2 out of 3 new replicas have been updated...
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```
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或者
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```
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deployment.apps/nginx-deployment successfully rolled out
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```
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**查看更新后的 Deployment 的详情：**
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* 更新（rollout）成功后，您可以执行命令 `kubectl get deployments` 以查看更新结果。输出信息如下所示：
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```
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NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
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nginx-deployment 3 3 3 3 36s
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```
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* 执行命令 `kubectl get rs` Deployment 的更新是通过创建一个新的 3 个副本数的 ReplicaSet 并同时将旧的 Replicaset 的副本数缩容到 0 个副本 来达成的。输出结果如下所示：
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```
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NAME DESIRED CURRENT READY AGE
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nginx-deployment-1564180365 3 3 3 6s
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nginx-deployment-2035384211 0 0 0 36s
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```
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* 执行命令 `kubectl get pods`，此时将只显示新的 Pod，输出结果如下所示：
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```
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NAME READY STATUS RESTARTS AGE
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nginx-deployment-1564180365-khku8 1/1 Running 0 14s
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nginx-deployment-1564180365-nacti 1/1 Running 0 14s
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nginx-deployment-1564180365-z9gth 1/1 Running 0 14s
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```
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* 如果您想要修改这些新的 Pod，您只需要再次修改 Deployment 的 Pod template。
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* Deployment 将确保更新过程中，任意时刻只有一定数量的 Pod 被关闭。默认情况下，Deployment 确保至少 `.spec.replicas` 的 75% 的 Pod 保持可用（25% max unavailable）
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* Deployment 将确保更新过程中，任意时刻只有一定数量的 Pod 被创建。默认情况下，Deployment 确保最多 `.spec.replicas` 的 25% 的 Pod 被创建（25% max surge）
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例如，如果您仔细观察上述 Deployment 的更新过程，您将注意到 Deployment Controller 先创建一个新 Pod，然后删除一个旧 Pod，然后再创建新的，如此循环，直到全部更新。Deployment Controller 不会 kill 旧的 Pod，除非足够数量的新 Pod 已经就绪，Deployment Controller 也不会创新新 Pod 直到足够数量的旧 Pod 已经被 kill。这个过程将确保更新过程中，任意时刻，最少 2 个 / 最多 4 个 Pod 可用。
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* 执行命令 `kubectl describe deployments` 查看 Deployment 详情，输出结果如下所示：
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```
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Name: nginx-deployment
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Namespace: default
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CreationTimestamp: Thu, 30 Nov 2017 10:56:25 +0000
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Labels: app=nginx
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Annotations: deployment.kubernetes.io/revision=2
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Selector: app=nginx
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Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
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StrategyType: RollingUpdate
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MinReadySeconds: 0
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RollingUpdateStrategy: 25% max unavailable, 25% 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:1.9.1
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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-1564180365 (3/3 replicas created)
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Events:
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Type Reason Age From Message
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---- ------ ---- ---- -------
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Normal ScalingReplicaSet 2m deployment-controller Scaled up replica set nginx-deployment-2035384211 to 3
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Normal ScalingReplicaSet 24s deployment-controller Scaled up replica set nginx-deployment-1564180365 to 1
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Normal ScalingReplicaSet 22s deployment-controller Scaled down replica set nginx-deployment-2035384211 to 2
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Normal ScalingReplicaSet 22s deployment-controller Scaled up replica set nginx-deployment-1564180365 to 2
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Normal ScalingReplicaSet 19s deployment-controller Scaled down replica set nginx-deployment-2035384211 to 1
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Normal ScalingReplicaSet 19s deployment-controller Scaled up replica set nginx-deployment-1564180365 to 3
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Normal ScalingReplicaSet 14s deployment-controller Scaled down replica set nginx-deployment-2035384211 to 0
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||||
```
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||||
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||||
此时，在 `Events` 中，您可以看到：
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||||
* 您创建 Deployment 时，Deployment Controller 创建了一个 ReplicaSet (nginx-deployment-2035384211) 并直接将其 scale up 到 3 个副本。
|
||||
* 当您更新 Deployment 时，Deployment Controller 先创建一个新的 ReplicaSet (nginx-deployment-1564180365) 并将其 scale up 到 1 个副本，然后 scale down 旧的 ReplicaSet 到 2。
|
||||
* Deployment Controller 继续 scale up 新的 ReplicaSet 并 scale down 旧的 ReplicaSet，直到最后，新旧两个 ReplicaSet，一个副本数为 3，另一个副本数为 0。
|
||||
|
||||
</el-tab-pane>
|
||||
|
||||
@ -21,3 +145,14 @@ description: 本文描述了如何在 Kubernetes 中更新 Deployment
|
||||
</el-tab-pane>
|
||||
|
||||
</el-tabs>
|
||||
|
||||
## 覆盖更新 Rollover （更新过程中再更新）
|
||||
|
||||
每创建一个 Deployment，Deployment Controller 都为其创建一个 ReplicaSet，并设定其副本数为期望的 Pod 数（ `.spec.replicas` 字段）。如果 Deployment 被更新，旧的 ReplicaSet 将被 Scale down，新建的 ReplicaSet 将被 Scale up；直到最后新旧两个 ReplicaSet，一个副本数为 `.spec.replias`，另一个副本数为 0。这个过程称为 rollout。
|
||||
|
||||
当 Deployment 的 rollout 正在进行中的时候，如果您再次更新 Deployment 的信息，此时 Deployment 将再创建一个新的 ReplicaSet 并开始将其 scale up，将先前正在 scale up 的 ReplicaSet 也作为一个旧的 ReplicaSet，并开始将其 scale down。
|
||||
|
||||
例如：
|
||||
* 假设您创建了一个 Deployment 有 5 个 nginx:1.7.9 的副本；
|
||||
* 您立刻更新该 Deployment 使得其 `.spec.replicas` 为 5，容器镜像为 `nginx:1.9.1`，而此时只有 3 个 nginx:1.7.9 的副本已创建；
|
||||
* 此时，Deployment Controller 将立刻开始 kill 已经创建的 3 个 nginx:1.7.9 的 Pod，并开始创建 nginx:1.9.1 的 Pod。Deployment Controller 不会等到 5 个 nginx:1.7.9 的 Pod 都创建完之后在开始新的更新
|
||||
|
||||
@ -7,6 +7,9 @@
|
||||
|
||||
**BUG 修复**
|
||||
|
||||
* 导入应用程序时，NodePort 的值丢失
|
||||
* 导出应用程序时，环境变量-容器组信息丢失
|
||||
|
||||
|
||||
* 存储卷声明去掉分配模式的字段
|
||||
* 存储卷声明增加 Volume Modes 字段
|
||||
@ -15,3 +18,5 @@
|
||||
* Pod Conditions: lastProbeTime/reason/message
|
||||
* Pod restartPolicy
|
||||
* 初始化容器不支持就绪检查
|
||||
* Service 配置里，一部分 端口用 NodePort， 一部分端口用 ClusterIP
|
||||
* 互联网访问入口，增加文档的链接
|
||||
|
||||
Reference in New Issue
Block a user