[et-mgmt-tools] Cobbler & inherited profiles

[Aaron Lippold]

Hello,

Is anyone working on the cobbler buildcd profile=x for 0.5.0? I know
that was talked about and if I can help then I'd like to.

Aaron

On 6/14/07, Michael DeHaan <mdehaan at redhat.com> wrote:
> I figured I would share a bit on what's been going on with upstream
> Cobbler lately.
>
> As Euclid suggested on IRC a while back, I'm moving Cobbler to a
> "even=stable, odd=unstable" release convention.  This makes the current
> cobbler release 0.4.8 stable, and in a week or so, I'll push Cobbler
> 0.5.0 out to F7-testing (but not FC6, as it has no "testing" yet).
> There will be RPMs, but no Fedora-7 or FC-6 push.  Not immediately, anyway.
>
> Why split off a testing release?   Lots of new cool stuff coming in.
> The most notable feature is support for profile inheritance.   A lot of
> the ideas for this suggestion came in from Adam Rosenwald (thanks, Adam)
> -- I believe there were some earlier discussions about this too, sorry I
> forget who was involved.    Anyhow, this feature is illustrated as follows:
>
> cobbler profile add --name=xyz --virt-ram=512 --virt-size=5
> --distro=distro_name --kickstart=/path
> cobbler profile add --name=xyz2 --inherit=xyz --virt-size=6
>
> In the above example, cobbler profile p2 is going to be the same as p1,
> even when p1 changes, except for an override in the --virt-size
> parameter.
> This can be seen by looking at the saved cobbler profile files, where
> you'll see a lot of parameters are stored as "<<inherit>>" which means,
> I don't have a setting, ask my parent.  And yes, there can be any number
> of levels of inheritance.
>
> A further example:
>
> cobbler import --path=/mnt/dvdiso --name=FC-6
> cobbler profile add --name=FC-6-xen-i386-webserver
> --inherit=FC-6-xen-i386 --kickstart=/path/to/special/kickstart
> cobbler profile add --name=FC-6-xen-i386-dbserver
> --inherit=FC-6-xen-i386 --kickstart=/path/to/another/kickstart
> cobbler profile edit --name=FC-6-xen-i386 --virt-ram=6
> cobbler profile add --name=FC-6-xen-i386-webserver-more-disk
> --inherit=FC-6-xen-i386-webserver --virt-disk=10
> cobbler sync
>
> In the above example, I've derived two profiles from the profile I get
> for free from the "cobbler import".   I have assigned different
> kickstarts to both of them.
> Then, I go and edit their parent kickstart, and have, effectively,
> changed the --virt-ram value for both of them.   A quick way to see what
> actually happens to  the
> "calculated" values of FC-6-xen-i386-webserver-moredisk is to look at
> the file in /var/www/cobbler/profiles/$name ... you'll see all the
> values -- and the cool thing is,
> that in 0.5.0, every single one of these values is available in Cheetah
> templating -- which is fairly cool.
>
> This inheritance blending also works for ks_meta (templating) variables
> and kernel options.  In those cases, you can add additional kernel
> options to existing options part of a parent profile, or you can
> override existing ones with new values.
>
> cobbler profile add --name=p1 ...
> cobbler profile add --name=p2 --inherit=p2 --ksmeta="moose=lodge"
>
> The above example would use all of the templating metadata values of p1,
> but would set the additional value of "moose" to the value "lodge".
>
> The implementation of the above is available now in git -- with only a
> bit of polishing still needed.   Namely, awareness of cascade updates so
> running sync on the entire
> cobbler tree is not required after an edit to a parent node.
>
> When is this useful?   The example Adam gave, and I think it's a good
> one, is if a site had multiple locations, with different policy rules
> between them, and one also wanted to have system roles (webserver,
> dbserver) underneath of each of these policies.   An inheritance system
> makes something like this possible.
>
> Right now, only profiles are inheritable (not distros or systems), and
> it's only single inheritance.  No, you should never need an OOP textbook
> to understand Cobbler.  That would be wrong :)
>
> Questions?  Comments?  Fire away.
>
> (Note that Cobbler 0.5.0 also contains dnsmasq support (including DNS!),
> edit/copy/rename commands, and being able to name systems after things
> that aren't MAC addresses -- so, if you're interested in any of the
> above, check out the git repo)
>
> Thanks!
>
> --Michael
>
>
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