[imp] Server Farms..

[Michael Bellears]

> Oliver Kuhl:
> > First of all I cannot tell you something about real 
> loadbalancers. But 
> > I can tell you something about our setup, which works via 
> dns-round-robin.
> 
> The greatest advantages in choosing a loadbalancer over 
> dns-round-robin is the ability to do healthchecking of the 
> realservers. If one server fails, it gets automaticly removed 
> from the server pool.

I agree - And our budget(fortunately) permits the purchase of a
loadbalancer.

> 
> At our site we use linux virtualserver
> (http://www.linuxvirtualserver.org). You should check it out.

I have looked at lvs - It does look very impressive.

> 
> > Our imp-servers are quite the same hardware. So I have a 
> > testing-machine with a little shell-script to sync all 
> necessary files 
> > with the production machines using rsync.
> 
> We use rdist for distribution of config files.

Thanks - I'll have a look.

Cfengine has also been suggested: (http://www.iu.hio.no/cfengine/) which
looks excellent.

And CVS is also a possibility - being able to trace back how the config
file was changed is certainly a bonus.

Someone else suggested CVS/subversion, and use cfengine to handle
deploying new versions of configs.

> 
> > >3. What about logfiles - We would have all users mail etc 
> on an NFS 
> > >share - Can you do the same for logfiles?(Or do you get locking 
> > >issues?)
> > >- From a statistical aspect, it would be a pain to have to combine 
> > >each "real" servers logfiles, then run analysis.
> 
> A simple merge-sort will do this. I can mail the script we 
> use if you are interested.

Certainly - Would appreciate it!

> You can also check out 
> mod_log_spread, a apache module for distributing logs in realtime.

Thanks again!

> 
> > > Also from a support
> > >perspective - How are support personnel supposed to know 
> which "real"
> > >server a client would actually be connecting to in order to see if 
> > >they are entering a wrong username/pass etc?
> 
> Make horde syslog to a central loghost.

Will do.

> 
> > >4. This is OT, but I thought I would ask anyway - Once we 
> have a "real"
> > >server setup they way we want - What imaging software can be used 
> > >(Quick recovery in the event of server failure (Eg. If 
> Total rebuild 
> > >is necessary), and also simple for addition of new "real" 
> server)?. I 
> > >would love a utility that can create a bootable CD from our SOE, 
> > >giving us the ability to just place this CD into the new server, 
> > >power up and in a couple of minutes we have a fully 
> functional server 
> > >ready to be placed into the server farm.
> 
> We use pxe and redhat's kickstart to install new servers. 
> Combined with rdist (which distributes configfiles) a new 
> server is up and running in about 5 minutes.

I have had some really positive feedback regarding systemimager - I'll
run it on a few test servers, and see how it goes.

Regards,
MB