[BlueOnyx:24448] Re: strange issue vsite and hostname

[Michael Stauber]

Hi Gerrit,

> Is there possible to see one common thing here?
> - vsite name was part of the first part of the server name.
> 
> Our server: 
> Vsite: *abc*.def.net
> Server: *abc*.xyz.net
> 
> Your server: 
> Vsite: 5210r. ??
> Server: 5210r.smd.net

This was actually the root cause of the issue that caused hostname
flippage between just hostname and FQDN.

I just went through all handlers and constructors on 5209R and 5210R to
find where this happens and identified the issue.

When we update /etc/hostname, we used to only set the hostname, not the
FQDN.

When we set the server name via "hostnamectl set-hostname
host.example.com --static", then this removes the transient hostname
from the hostnamectl output. The restart of systemd-hostnamed or any
network related transaction via NetworkManager parses /etc/hostname,
encounters the "short" hostname and then sets this as Transient hostname
again. Then we end up with having both transient and static hostname.

The fix was to always write the full FQDN into /etc/hostname. That way
it doesn't flip and the transient hostname is no longer set or used, as
it's superseded by the static hostname.

I just published YUM updates for 5209R and 5210R which have that fixed.

-- 
With best regards

Michael Stauber