Resolving since it sounds like this is possible already.

The alarm system already supports system wide notifications. But not 
locking out. But this should easily be possible with a pre- or 
postauthenticate hook always returning false. It wouldn't affect 
logged-in users, but noone can login anymore.

The tricky part, I think, would be architecting it in a way such that 
the alarm would work regardless if you had 1 or N horde front ends.



It'd be doable if you had a common NFS-mounted directory amongst all 
the cluster boxes (as we do) but I'm not sure how to do it otherwise 
(aside from making some change on each box individually)

This idea came up recently in a project I am working on as well.  At 
the time, my idea was to possibly use the Horde_Alarm system to do 
this.  But Jan is the one writing that system so he might be the 
better person to comment on this.

Would it be possible to add some ability to spawn a popup or something 
to notify users about things like impending system shutdown or the 
like?  We can add a motd message now which is helpful for certain 
things but once the users log in we have no way of notifying them that 
the system is about to go down and that they should save their work or 
risk losing it.



Along the same lines it would be handy to have a lockout feature that 
would allow users that were already logged in to finish what they were 
doing and log out but wouldn't allow any new logins until the admin 
re-enabled logins.  It's not a critical feature but we get a lot of 
flack when we have to bring the service down for whatever reason and 
there are hundreds or thousands of people still logged in.