文章目录

• 场景:
• 1. 创建示例环境
• 2. 升级版本
• • 2.1 edit 配置文件的第37行，改为指定版本
• 3. 回退版本
• • 3.1 查看历史版本信息
  • 3.2 查看需要回退到的版本信息
  • 3.3 查看历史版本1的详细信息
  • 3.4 执行回退命令
• 结论:

场景:

我们在做部署软件的时候经常会遇到软件升级与回退。

1. 创建示例环境

根据k8s 官网示例，创建一个yaml文件
https://kubernetes.io/docs/concepts/workloads/controllers/deployment/

apiVersion: apps/v1
kind: Deployment
metadata:name: nginx-deploymentlabels:app: nginx
spec:replicas: 3selector:matchLabels:app: nginxtemplate:metadata:labels:app: nginxspec:containers:- name: nginximage: nginx:1.14.2ports:- containerPort: 80

创建deployment 实例

root@k8s-master:~# kubectl create -f label28.yaml
deployment.apps/nginx-deployment created
root@k8s-master:~# kubectl get deployments.apps
NAME               READY   UP-TO-DATE   AVAILABLE   AGE
nginx-deployment   3/3     3            3           14s
root@k8s-master:~# kubectl get deployments.apps -o wide
NAME               READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES         SELECTOR
nginx-deployment   3/3     3            3           21s   nginx        nginx:1.14.2   app=nginx

ouput:

升级软件版本
将 nginx:1.14.2 升级到 1.21.6

2. 升级版本

2.1 edit 配置文件的第37行，改为指定版本

root@k8s-master:~# kubectl edit deployments.apps nginx-deployment
deployment.apps/nginx-deployment edited

ouput:

从结果可以看出nginx已经升级成功

3. 回退版本

如果升级的版本有问题，经常会有回退的动作

3.1 查看历史版本信息

root@k8s-master:~# kubectl rollout history deployment nginx-deployment --show-managed-fields
deployment.apps/nginx-deployment
REVISION  CHANGE-CAUSE
1         
2         root@k8s-master:~# kubectl rollout history deployment nginx-deployment --revision 1
deployment.apps/nginx-deployment with revision #1
Pod Template:Labels:       app=nginxpod-template-hash=6595874d85Containers:nginx:Image:      nginx:1.14.2Port:       80/TCPHost Port:  0/TCPEnvironment:        Mounts:     Volumes:      root@k8s-master:~# kubectl rollout history deployment nginx-deployment --revision 2
deployment.apps/nginx-deployment with revision #2
Pod Template:Labels:       app=nginxpod-template-hash=6494477f49Containers:nginx:Image:      nginx:1.21.6Port:       80/TCPHost Port:  0/TCPEnvironment:        Mounts:     Volumes:      

3.2 查看需要回退到的版本信息

查看当前版本信息，现在需要从当前版本2回退到版本1.

root@k8s-master:~# kubectl describe deployments.apps nginx-deployment
Name:                   nginx-deployment
Namespace:              default
CreationTimestamp:      Mon, 20 Mar 2023 04:39:37 +0800
Labels:                 app=nginx
Annotations:            deployment.kubernetes.io/revision: 2
Selector:               app=nginx
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=nginxContainers:nginx:Image:        nginx:1.21.6Port:         80/TCPHost Port:    0/TCPEnvironment:  Mounts:       Volumes:        
Conditions:Type           Status  Reason----           ------  ------Available      True    MinimumReplicasAvailableProgressing    True    NewReplicaSetAvailable
OldReplicaSets:  
NewReplicaSet:   nginx-deployment-6494477f49 (3/3 replicas created)
Events:Type    Reason             Age   From                   Message----    ------             ----  ----                   -------Normal  ScalingReplicaSet  19m   deployment-controller  Scaled up replica set nginx-deployment-6595874d85 to 3Normal  ScalingReplicaSet  13m   deployment-controller  Scaled up replica set nginx-deployment-6494477f49 to 1Normal  ScalingReplicaSet  13m   deployment-controller  Scaled down replica set nginx-deployment-6595874d85 to 2Normal  ScalingReplicaSet  13m   deployment-controller  Scaled up replica set nginx-deployment-6494477f49 to 2Normal  ScalingReplicaSet  13m   deployment-controller  Scaled down replica set nginx-deployment-6595874d85 to 1Normal  ScalingReplicaSet  13m   deployment-controller  Scaled up replica set nginx-deployment-6494477f49 to 3Normal  ScalingReplicaSet  13m   deployment-controller  Scaled down replica set nginx-deployment-6595874d85 to 0
root@k8s-master:~#

3.3 查看历史版本1的详细信息

root@k8s-master:~# kubectl rollout history deployment nginx-deployment --revision=1
deployment.apps/nginx-deployment with revision #1
Pod Template:Labels:       app=nginxpod-template-hash=6595874d85Containers:nginx:Image:      nginx:1.14.2Port:       80/TCPHost Port:  0/TCPEnvironment:        Mounts:     Volumes:      

3.4 执行回退命令

root@k8s-master:~# kubectl rollout undo deployment nginx-deployment --to-revision=1
deployment.apps/nginx-deployment rolled back
root@k8s-master:~# k describe deployments.apps nginx-deployment
Name:                   nginx-deployment
Namespace:              default
CreationTimestamp:      Mon, 20 Mar 2023 05:08:59 +0800
Labels:                 app=nginx
Annotations:            deployment.kubernetes.io/revision: 3
Selector:               app=nginx
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=nginxContainers:nginx:Image:        nginx:1.14.2Port:         80/TCPHost Port:    0/TCPEnvironment:  Mounts:       Volumes:        
Conditions:Type           Status  Reason----           ------  ------Available      True    MinimumReplicasAvailableProgressing    True    NewReplicaSetAvailable
OldReplicaSets:  
NewReplicaSet:   nginx-deployment-6595874d85 (3/3 replicas created)
Events:Type    Reason             Age              From                   Message----    ------             ----             ----                   -------Normal  ScalingReplicaSet  5m19s            deployment-controller  Scaled up replica set nginx-deployment-6595874d85 to 3Normal  ScalingReplicaSet  4m37s            deployment-controller  Scaled up replica set nginx-deployment-6494477f49 to 1Normal  ScalingReplicaSet  4m36s            deployment-controller  Scaled down replica set nginx-deployment-6595874d85 to 2Normal  ScalingReplicaSet  4m36s            deployment-controller  Scaled up replica set nginx-deployment-6494477f49 to 2Normal  ScalingReplicaSet  4m35s            deployment-controller  Scaled down replica set nginx-deployment-6595874d85 to 1Normal  ScalingReplicaSet  4m35s            deployment-controller  Scaled up replica set nginx-deployment-6494477f49 to 3Normal  ScalingReplicaSet  4m34s            deployment-controller  Scaled down replica set nginx-deployment-6595874d85 to 0Normal  ScalingReplicaSet  8s               deployment-controller  Scaled up replica set nginx-deployment-6595874d85 to 1Normal  ScalingReplicaSet  7s               deployment-controller  Scaled down replica set nginx-deployment-6494477f49 to 2Normal  ScalingReplicaSet  5s (x4 over 7s)  deployment-controller  (combined from similar events): Scaled down replica set nginx-deployment-6494477f49 to 0
root@k8s-master:~# kubectl rollout history deployment nginx-deployment
deployment.apps/nginx-deployment
REVISION  CHANGE-CAUSE
2         
3         

output:

结论:

可以看到这里执行版本回退之后，之前的版本1被版本3替代了。