版本回滚
回滚到第一次的版本：
helm rollback --debug mysql 1
[debug] Created tunnel using local port: '60303'
[debug] SERVER: "localhost:60303"
Rollback was a success! Happy Helming!
查看mysql release的版本信息，当前已经回滚到REVISION为1的版本：
$ helm hist mysql
REVISION UPDATED STATUS CHART DESCRIPTION
1 Tue Sep 12 07:31:49 2017 SUPERSEDED mysql-0.2.8 Install complete
2 Tue Sep 12 07:44:00 2017 SUPERSEDED mysql-0.2.8 Upgrade complete
3 Tue Sep 12 08:50:48 2017 DEPLOYED mysql-0.2.8 Rollback to 1
https://helm.sh/docs/helm/helm_rollback/