004模拟一次deployment的上线发布回滚
创建一个名为nginx的deployment初始副本为2，然后修改nginx的镜像tag，最后在回滚到之前的版本
root@k8s-192-168-0-17:/home/node1# kubectl create deployment nginx --image=docker.io/library/nginx:1.21.6 --replicas=2
deployment.apps/nginx created
root@k8s-192-168-0-17:/home/node1# kubectl get deployment nginx -o wide -w
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR
nginx 2/2 2 2 22s nginx docker.io/library/nginx:1.21.6 app=nginx
root@k8s-192-168-0-17:/home/node1# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-784757bdfb-bs4rt 1/1 Running 0 42s 172.20.182.150 k8s-192-168-0-11 <none> <none>
nginx-784757bdfb-jjmzv 1/1 Running 0 43s 172.20.177.25 k8s-192-168-0-19 <none> <none>
# 注意这里的版本号
root@k8s-192-168-0-17:/home/node1# curl 172.20.182.150/1
<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx/1.21.6</center>
</body>
</html>
root@k8s-192-168-0-17:/home/node1# kubectl set image deployment/nginx nginx=docker.io/library/nginx:1.25.1
deployment.apps/nginx image updated
root@k8s-192-168-0-17:/home/node1# kubectl annotate deployment/nginx kubernetes.io/change-cause="image updated to 1.25.1"
deployment.apps/nginx annotated
root@k8s-192-168-0-17:/home/node1# kubectl rollout history deployment nginx
deployment.apps/nginx
REVISION CHANGE-CAUSE
1 <none>
2 image updated to 1.25.1
# 注意这里的版本号 已经换成 1.25.1 了
root@k8s-192-168-0-17:/home/node1# curl 172.20.182.153/1
<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx/1.25.1</center>
</body>
</html>
root@k8s-192-168-0-17:/home/node1# kubectl set image deployments/nginx nginx=nginx:1.21.6
deployment.apps/nginx image updated
root@k8s-192-168-0-17:/home/node1# kubectl annotate deployment/nginx kubernetes.io/change-cause="image updated to 1.21.6"
deployment.apps/nginx annotated
root@k8s-192-168-0-17:/home/node1# kubectl get pod -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-796bdc6f77-66hcm 1/1 Running 0 35s 172.20.182.154 k8s-192-168-0-11 <none> <none>
nginx-796bdc6f77-n5wng 1/1 Running 0 49s 172.20.177.29 k8s-192-168-0-19 <none> <none>
# 注意这里的版本号 已经换成 1.21.6 了
root@k8s-192-168-0-17:/home/node1# curl 172.20.182.154/1
<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx/1.21.6</center>
</body>
</html>
## 假设我们这次升级版本出现了问题 那么我们查看历史，我们要回滚到1.25.1
root@k8s-192-168-0-17:/home/node1# kubectl rollout history deployment nginx
deployment.apps/nginx
REVISION CHANGE-CAUSE
1 <none>
2 image updated to 1.25.1
3 image updated to 1.21.6
# --to-revision=2 就是上一步的索引
root@k8s-192-168-0-17:/home/node1# kubectl rollout undo deployment nginx --to-revision=2
deployment.apps/nginx rolled back
# 这里版本号已经回滚到1.25.1
root@k8s-192-168-0-17:/home/node1# curl 172.20.177.30/1
<html>
<head><title>404 Not Found</title></head>
<body>
<center><h1>404 Not Found</h1></center>
<hr><center>nginx/1.25.1</center>
</body>
</html>
# 我们再查询rs
root@k8s-192-168-0-17:/home/node1# kubectl get rs
NAME DESIRED CURRENT READY AGE
nginx-784757bdfb 0 0 0 19m
nginx-796bdc6f77 0 0 0 16m
nginx-79df7c55d7 2 2 2 19m