[et-mgmt-tools] PATCH: koan: --no-cobbler --virt

[Michael DeHaan]

Gavin Romig-Koch wrote:
> Michael DeHaan wrote:
>>
>> I'm not sure we should add this.   Discussion is welcome.
>>
> Thanks for the chance to discuss this.  In re-reading this before 
> sending it, I realize that it is longer and "preachy-er" than I had 
> hoped.  Please forgive my weak writing skills.
>
> Within Red Hat Support we have a need for a single tool that can do 
> kickstart based installs, of either actual hardware or virtual 
> machines.  For each issue that comes in (that isn't solvable by just 
> looking at the case), we need to do some sort of local reproduction of 
> the issue, if that's possible.  This happens several times a week, if 
> not more, for each engineer working cases within support.  As you 
> know, we support three major releases, multiple sub-configurations 
> within that, and our customers are often reluctant and sometimes 
> unable to upgrade to the latest update within a release without 
> assurances from us that it will solve their problem.   All this is my 
> way of emphasizing that we can't reduce our set of possible installs 
> to a countable, nameable, predefined set of profiles.  Each case is a 
> new profile, and often we must tweak that profile several times to 
> find out exactly what combination is needed to reproduce the problem.
>
> While reproducablity is important, it is almost never necessary to 
> reproduce the customers  exact hardware or virtual machine 
> parameters.  On the other hand, it is almost always necessary to 
> reproduce (at least part of) the software enviroment they have.
>
> It would be possible to use a Cobbler server in this environment.  
> Each engineer could manage his own Cobbler server, or we could create 
> a central Cobbler server, and build some tools that allowed engineers 
> to check in new profiles/systems, delete profile/systems, and 
> implement some nameing convention for profiles.  But this would just 
> be extra work to make our environment fit the model of the typical 
> data center environment.
This doesn't seem to be hard to establish to me, there's work sure, but 
it may lead to time savings in the end as Cobbler has ways of inheriting 
profiles from one another and doing some other interesting things.   
There's also a pretty powerful templating system for building kickstarts 
based on, well, templates.   Plus, since you're local, I'd be glad to 
offer assistance :)
>
> It would also be possible to use koan hardware re-installs, and 
> virt-install for virt installs, but it seemed useful to me to have a 
> single tool (with a single set of options) that did what I see as a 
> single function - a kickstart based install.
With Cobbler, the idea is that there are things you are going to need 
for a baremetal install server -- hosting of the content, TFTP (in some 
cases), DHCP (in some cases), etc.   It takes care of all of these, 
while also offering centralized management.   Given you probably only 
want to host trees once (and Cobbler can import from NFS very easily), 
this seems to be a good fit still.   Depending on your scenario, you may 
want to grant accounts to the WebUI, or more likely just grant su access 
to cobbler for users that need to add entries.    It depends on your 
configuration and I'd like to hear more about it, but it's not different 
from how Cobbler would be used in development setups (which is one of 
the things it's useful for...).

>
> We could also build such a tool.  We have a tool that does largely the 
> same thing as koan --no-cobbler --replace-self does, but does not do 
> --virt installs. 

If you're worried about koan --replace-self and virt-install mismatch, 
the tool you're talking about is a small shell script :)

> I was looking at how to extend it to also do virt installs, when I 
> discovered Koan.  At the time I knew that Koan was really just an 
> extension of Cobbler, but I was hopeing that Koan was willing to grow 
> into a more general kickstart-over-a-network tool, able to use 
> Cobbler, but not entirely dependent on it.  

Koan is basically the client piece that allows Cobbler to do things 
Cobbler can't do strictly from a network perspective.

> I understand any reluctance, or objection, to growing the purpose of 
> Koan -- do one thing, do it well -- is a good maxim for programs and 
> libraries and maybe even people, but I believe Koan can grow outside 
> of it's current roll of Cobbler-helper, and still be following this 
> maxim.
>

It could, but I'm not sure where this leaves virt-install... which does 
basically the same thing.    Virt-install seems to handle this niche, 
and if you outgrow virt-install, you pick up Cobbler...

> While RH's support's needs are perhaps unique in the volume of 
> re-installs we do, I don't believe we are unique in our need for a 
> single tool to do kickstart based installs of either virtual or actual 
> hardware.   Does Koan want to be that tool, to stay within it's 
> current role?
>
Koan does, but it wants Cobbler to go with it, and I believe with 
Cobbler the advantages are worth it if you want a deployment server, 
rather than building it yourself.   If there's something you need in 
Cobbler, we can definitely work to improve that just as easily as we can 
make koan work without Cobbler.

>                                                                                                                     
> -gavin....
>
>
>
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