[et-mgmt-tools] Cobbler and Koan for _my_ needs

Matthias Saou thias at spam.spam.spam.spam.spam.spam.spam.egg.and.spam.freshrpms.net
Thu Sep 27 15:03:06 UTC 2007

Michael DeHaan wrote :

> >> Cobbler is designed for central configuration, so it can be your MAC 
> >> database.
> >
> > Can it really? For Xen guests?
> Yes.
> koan --virt --system=AA:BB:CC:DD:EE:FF --server=cobbler.example.org

Hmmmm, indeed, this works, but this makes things uglier for me.
Renaming my system from 'test' to '00:16:3e:01:ec:2e' in Cobbler and
using --system=00:16:3e:01:ec:2e instead of --system=test makes the
virtual guest get the intended the MAC address, but :
- I now have a system called '00:16:3e:01:ec:2e' in the WebUI instead
of the much more human friendly 'test'.
- I now have a Xen guest called '00_16_3e_01_ec_2e' instead of the much
more human friendly 'test'.

When I run 'xm list' and see a bunch of host names, it's much quicker
for me to stop/restart/connect-to any of the guests than with having a
list of 00_16_3e_xx_xx_xx entries :-/ Same for the WebUI...

So it seems to me that there is too much logic on the Koan side, which
makes it impossible to use a friendly name and have it use the MAC
address configured in the Cobbler.

> > I've played some more with Koan and Xen guests, but apparently even
> > telling Koan to install a system which has a specific MAC address in
> > its Cobbler system details creates the Xen guest file with a random MAC
> > address. 
> What cobbler and koan version is this?

The 0.6.2-1 you posted yesterday. But see above : Invoking the system
by "friendly name" gets a random MAC address, even if the system has a
MAC address configured in Cobbler, but renaming the system to its MAC
address "fixes" this.

> > My DHCP server has only static entries, which means that if
> > Koan used the MAC address I've put in the Cobbler system it would work,
> > but the random MAC address won't ever be able to get an IP address (and
> > this corporate network _must_ stay this way).
> >
> > Using Koan's "--display", it does seem like the MAC address isn't
> > obtained from Cobbler.
> >
> > Am I maybe simply doing something wrong?
> >
> > On a related note, I do see "virt_path" and "virt_type" in the Cobbler
> > systems, but I don't see "virt_ram", which would be very useful to be
> > able to set on a per-system basis in my case.
> >   
> Conceptually, profiles are there to describe what the purpose of the 
> system is and it's requirements.
> If a profile states that a configuration needs "X" amount of RAM, it is 
> important to honor that.
> The overrides on storage are for cases such as a development profile 
> being created centrally, and the local user
> wanting to install it in a different location (for instance, say they 
> had a large partition on the domU they wanted
> to use).
> Overriding the amount of virtual RAM on the koan command line is 
> possible, but we do not want folks
> thinking of RAM requirements for individual systems because that defeats 
> the point of the profile
> abstraction.

I don't want to override anything on the koan command line. I'm more
than fine with having everything in Cobbler!

But in my case, I'd need my profile to be :
- virt_path: /dev/data/$name,/dev/data/swap$name
  (I'm not sure if this can be done, I can live with overriding it in
   all system configurations, which is what I've done for now)
- virt_ram: 512

Then the default system associated to be :
- virt_path: <<inherit>>
- virt_ram: <<inherit>>
...where I only change the name, hostname and MAC address.

Here I'd like to be able to change virt_ram on a per-system basis, but
it doesn't seem possible currently (or maybe I just need to "manually"
add it to the system file?).

In my scenario, we're not talking about thousands of servers, more like
a few dozens in each location, with locations being very remote and
having each their own cobbler instance, so I'm thinking about creating
a system entry in Cobbler for each and every host and guest I have.

Obviously, they'll all inherit most of their configuration from a given
profile, but I'll need to override some settings here and there.


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