[Piuparts-devel] concerning master-slave packaging

[Holger Levsen]

Hi,

On Mittwoch, 13. Juni 2012, Dave Steele wrote:
> > IMHO piuparts-master and piuparts-slave need to be packaged
> > independently. That makes the whole thing much more difficult and
> > requires manual configuration (at least if a standalone slave is being
> > set up). But it is the only useful solution for the use case: there is
> > one master (and one reporting process + webserver), but many slaves on
> > different (virtual) machines, serving possibly different architectures
> > (maybe some in qemu).
> I challenge the "only useful solution" part. It is not difficult to
> set this up with a piuparts-server. If you are provisioning the VMs,
> you have a recipe that pulls the slave code (piuparts-server) and the
> correct configuration file. Add to that recipe a delete of the master
> cron, apache conf, and authorized keys, and disable (or delete)
> apache. That should give you effective standalone slaves. There is a
> cost associated with carrying along apache and the master files, but
> it is small relative to launching a separate VM in the first place.

What I ment was that (I think) the only sensible solution which can work out 
of the box when _just_ using "apt-get install..." is a single-host only setup.

(well, unless we implement auto discovery of slaves...)
 
> I question whether there is substantial enough benefit there to
> justify the cost.

which cost?

> My second objection to master + slave is the idea that we (I, anyway)
> don't know enough yet about how this should be set up.

hm, we have several such setups running?!
 
> Consider security. The slave runs, as root, code signed by any one of
> 1000+ keys. 

yes, we know about this. how is this relevant here?

> Should all that cruft be separated from slave via piuparts-master, or
> piuparts-public-display-thingie? Or is it even enough to matter? I
> don't think we know the answer yet.

Honestly, I dont get your question...
 
> > And for the single architecture case that we do currently multiple
> > *distributed* slaves will give nice speedups.
> I'm on a new server (power supply failure). I had intended to go hog
> wild with remote slaves, but I don't see the point now. The standalone
> server went through sid in a day the first time through. It doesn't
> seem worth it to distribute slaves for performance. Piatti should be
> fine with a hardware upgrade. ... I don't know how I would feel with
> 50 sections.

well, an hardware upgrade is probably 3k USD or more. And it's not coming. 
What's coming is putting piatti in virtualisation. And then it's probably 
easier to add more slaves than to have a powerful VM. Also, typical multi-core 
machines (say 16-32 cpus) run their cores on a a lower frequency than 
quadcores...


cheers,
	Holger