What is hanging systemctl?

[Gordon Messmer]

On 10/19/2015 05:35 AM, Tom Horsley wrote:
> Looks like it wasn't just cron related stuff. When I finally
> made it to the cleanup phase of the update, every single
> try-restart hung till I killed it for every service being
> updated, not just cron related stuff.

Yes, that is expected.  Any user lookup will hang.  Any daemon that 
starts which doesn't run as root will need to look up the user as which 
it runs, as well as any group memberships.  That means that even when 
the user is in the local files, the network identity systems are queried 
for group memberships, and that will hang.

sssd might fix that, but NIS isn't natively supported, so you'd have to 
do pass-through authentication.  I'm not familiar with pass-through 
auth, so I'm unsure if that would actually provide a work-around.  As 
long as you're using NIS, you probably should ensure that there are 
redundant servers.