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

Michael DeHaan mdehaan at redhat.com
Thu Sep 27 15:20:41 UTC 2007

Matthias Saou wrote:
> 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'.

Hmm, this looks like leftover bits from when the name had to be a MAC. 
Since the MAC
is a seperate field now, I'll see why it's not being used if it's provided.

However, even so, you can still add the optional parameter --virt-name 
to name your guest.

koan --virt --system=AA:BB:CC:DD:EE:FF --server=cobbler.example.org --virt-name=blinky

> 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...
See above...
> 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.
Nope... even if the "find out what the MAC address is set to" is 
currently fouled
up for virtual machines when the name is not a MAC, you still have a way 
to specify
a name override.
> 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
This would put them in two directories, which should be sufficient:


> 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?).
It's not like we couldn't add it, it just seems to go against the design 
of having profiles
that define the requirements of what they are running. This is the same 
reason you
can't request more virtual disk for a specific system -- the idea is 
that you would
use inherited profiles to do this, and then just map the system to the 
profile that it
was going to be assigned to.

> 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.
Sure, this is good...
> Obviously, they'll all inherit most of their configuration from a given
> profile, but I'll need to override some settings here and there.
Hmm, yeah, take a look at the existing subprofile support, which may help.

(The argument is --inherit and is covered in the manpage).

> Matthias

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