当升级出现异常时，执行回滚即可。

[root@hdss7-21 ~]# kubectl rollout history deployment nginx-deploy -n app # 查看历史版本记录
deployment.extensions/nginx-deploy 
REVISION  CHANGE-CAUSE
1         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.12.yaml --record=true
2         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.13.yaml --record=true
3         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.14.yaml --record=true
4         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.15.yaml --record=true
[root@hdss7-21 ~]# kubectl rollout undo deployment nginx-deploy -n app
[root@hdss7-21 ~]# kubectl rollout history deployment nginx-deploy -n app # 版本3已经被版本5替代
deployment.extensions/nginx-deploy 
REVISION  CHANGE-CAUSE
1         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.12.yaml --record=true
2         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.13.yaml --record=true
4         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.15.yaml --record=true
5         kubectl apply --filename=http://k8s-yaml.od.com/base_resource/deployment/nginx-v1.14.yaml --record=true
[root@hdss7-21 ~]# kubectl get pod -n app -l partition=website -L version 
NAME                            READY   STATUS    RESTARTS   AGE     VERSION
nginx-deploy-7c5976dcd9-2kps8   1/1     Running   0          2m20s   v1.14
nginx-deploy-7c5976dcd9-bqs28   1/1     Running   0          2m6s    v1.14
nginx-deploy-7c5976dcd9-jdvps   1/1     Running   0          2m13s   v1.14
nginx-deploy-7c5976dcd9-vs8l4   1/1     Running   0          116s    v1.14
nginx-deploy-7c5976dcd9-z99mb   1/1     Running   0          101s    v1.14
[root@hdss7-21 ~]# kubectl get rs -n app -l tier=slb -L version
NAME                      DESIRED   CURRENT   READY   AGE    VERSION
nginx-deploy-5597c8b45    0         0         0       3h7m   v1.12
nginx-deploy-6695fd9655   0         0         0       12m    v1.15
nginx-deploy-6bd88df699   0         0         0       3h7m   v1.13
nginx-deploy-7c5976dcd9   5         5         5       34m    v1.14