what is considered the best way to shutdown and restart an hypervisor, supposing plain CentOS 7 host?

For example to cover these scenarios:

1) update host from 4.0 to 4.1

2) planned maintenance to the cabinet where the server is located and take the opportunity to update also OS packages

My supposed workflow:

- put host into maintenance

- yum update on host

- shutdown os from inside host (because from power mgmt it is brutal power off / power on) 

--> should I get any warning from web admin gui in this case, even if the host was in maintenance mode?

- power mgmt -> start from webadmin gui

(or power on button/virtual button at host side?)

Would be advisable to put inside power mgmt functionality some logic about os mgmt, so for example, if action is restart, first try to shutdown OS and only in case of failure power off/power on?

Thanks in advance,

Gianluca