Re: [gentoo-server] New GSDS snapshot

[Martin Hajduch]

hi !

> Network configuration should really be automated since the client will
> have to pull packages over the network and do other network related
> tasks. Currently, no, it doesn't do this automagically, but it will.
> It will also handle HA situations like multiple cards, spanning tree
> and trunking configs, and other goodies. How? The magic of cfengine,
> probably. If the client is destined to run dhcp, hey, even better.

i can imagine automated network configuration when client is supposed to 
get IP via dhcp
i can even imagine automated configuration of basic networking (here can 
be a problem with multiple network cards and network topology, but 
cfengine could try interfaces one by one until it gets connected to 
deployment server, etc ...)
but i really can't imagine automated configuration of HA, multiple 
cards, etc ... you could end up with a separate profile for every server 
and it could result in too much overhead (well - i can imagine it but 
... i will get to this later)
such configuration is not on the server level, you have to go higher - 
you need to have an overview of the network topology, which interface 
can access which part of the network and what is the purpose of this 
interface (which services should be running there, etc ...)
of course, i would be glad to see a software capable of doing it 
automatically, but unless it can read my thoughts, i doubt that it will 
be able to configure it as i want ;-)

> The idea is to minimize the work required for mid to large networks,
> so if some post flight sysadmin work is required, so be it. We won't
> be able to handle every conceivable set up out there (but that doesn't
> mean we're not going to plan that way).

i see a big potential in deploying client machines -> they are usually 
very similar, no complicated networking since everything can be driven 
from servers (dhcp, cups, proxy config, etc ...)
having a possibility of adding fully configured client just by booting 
it from a special CD would be definitely great for any sysadmin in a 
company using linux (gentoo) as a desktop platform

i'm a little bit skeptic about smaller 'server networks', imagine you 
have 2-5 web servers, 2 database servers, 2-4 application servers - if 
you could do this with 3 profiles, it would be good
but i'm afraid you can't; you need (i believe) primary/secondary 
database server profiles; you may have different applications spread 
over application servers; etc ... (or a clever, sophisticated way of 
profile building blocks and their combining ...)
of course, deploying openmosix cluster with 100 nodes which are more or 
less identical - i believe that GSDS would do great in such case

at the end of the day, it all depends on how sophisticated your 
configuration engine will be

to be somehow constructive, here is an example how it *could* work for 
smaller 'server networks' - just some brainstorming, don't take it very 
seriously ;-):

- you need a concept for a 'service'; each service can have multiple 
service profiles (configuration sets); service can be something very 
basic like networking (service profile contains IP, proxy settings), 
apache (service contains httpd.conf and others ...), or custom 
application; it has start/stop script, log files which need to be 
rotated, possibly some dependencies (to tie some maintenance actions 
with a server running a service))
- syntax of service configuration allows you to include other services, 
building bigger and bigger blocks
- you have some kind of 'aliases' for processing of configuration files; 
imagine that you have web servers, and you have a separate network 
profile with IP address for every web server; it defines 'alias', 
something like 'networking.primary.IP' or so ...
then you have service 'apache', profile contains httpd.conf and in 
httpd.conf you use alias 'networking.primary.IP' - configuration engine 
replaces this alias with primary IP address of the actual web server
this is just a stupid example .. but should explain what i mean with 
'aliases' ;-)
- you can create machine profiles manually just by writing a list of 
services and profiles to use into a file, something like:
MACHINE A
service.networking: web1
service.apache: default

MACHINE B
service.networking: web2
service.apache: default

by using aliases, apache profile 'default' will be customized with IP 
addresses of both web servers
what would be also important is that you could reference other machines; 
so that when configuring MACHINE B, you can use alias like 'MACHINE 
A.service.networking.primary.IP' or so ...

these were just some thoughts

however - last but not least - this is (IMHO) not a deployment software, 
this is, more or less, kind of auto-configuration framework for 
services/applications/servers
of course, the fact that it is automated makes it suitable for use in a 
deployment process

regards,
martin