System Maintenance page while applying the updates ?

Hello Good Morning All Experts !

I am trying to understand how the other schools doing while applying the system updates like Pum updates/ PeopleTools minor patch updates to the databases

We have a A10 Loadbalancer outside the webserver, so the PIA  login url will be accessed via the loadbalancer.

How are you broadcasting the message to the users

for example i have 2 scenarios

1). Scheduled maintenance : While the updates are going on PIA will be up & down, but we need to restrict the users not to have the access to the log in to PIA page at all but internally for the IT team who is working on applying the updates they need to have the access to PIA (when its up).