informations about boot sequence (Re: F15 - mysql start problem)

[Bill Nottingham]

Adam Williamson (awilliam at redhat.com) said: 
> Neither b) nor c) is a hack; they're both improvements in behaviour
> whether or not systemd is involved. It's simply more robust for a server
> to be able to run before the network connection is available (and hence
> across state changes). You don't explain why you think such a patch
> wouldn't be accepted upstream.
> 
> > in order to solve *one* of the possible configuration
> > issues that might cause them to not start correctly before the basic
> > expected network support services are available.  In particular, so far
> > as I can tell from the discussion at bug #703215, systemd is entirely
> > incapable of supporting services that need to do DNS lookups at start.
> 
> That's not true; Tomasz Torcz wrote earlier in this thread "We have
> hackish NetworkManager-wait-online.service which can be requested
> in such cases."

To be more precise:

If enabling NetworkManager-wait-online.service does *not* fix your problem
on normal boots (where networking doesn't fail/timeout entirely), we want to
know about it, and we can fix that.

However, network startup has not been synchronous by default with
NetworkManager ever since it was introduced; there has always been a race
here. To be sure, systemd, by introducing parallelization into the startup,
has made that race more prominent.

Bill