[CentOS-devel] Question about generating a spin of CentOS 7

[Jim Perrin]

On 10/30/2014 10:28 AM, Steven Falco wrote:
> On 10/30/2014 10:59 AM, Jim Perrin wrote:
>>
>>
>> On 10/28/2014 10:49 AM, Steven Falco wrote:
>>> I am interested in generating a spin of CentOS 7, but I'm
>>> having trouble identifying the correct tool to compose an
>>> ISO image.
>>
>> For what reason? Is this something that would benefit others
>> (could/Should it be a sig?)
> 
> I have been asked to create a customized install DVD that
> would automatically install - i.e. use a custom kickstart
> file.  To do that, I would add the ks file to the isolinux
> directory, and patch isolinux.cfg to pass my ks file to
> anaconda via the kernel cmd line.
> 
> I can do that manually by manipulating the official iso file.
> It is a lengthy series of steps, extracting the squashfs.img
> file, then the rootfs.img, then making my changes, and finally
> putting everything back together.  In short, a total kludge. :-)


Sounds mostly like the officially documented procedure from 4/5/6 that's
been in place for a while. In my opinion it's a terrible way to do
things, and I much prefer pxe and networked installs as you get updates,
avoid rebuilding media, etc.

> Instead, I'd like to be able to reproduce the method by which
> the official iso file is constructed.  I'd want to be able to
> do that on my local machine rather than using any CentOS
> resources, because I don't think this particular spin would be
> of any interest to the community.  However, the method of
> generating a custom DVD probably would be of interest to a lot
> of people.
> 
> I've actually made a fair amount of progress in the last
> few days.  First, I used pungi to reconstruct a Fedora 20
> iso which taught me how that process works.  It also gave
> me a good log file of a successful pungi build.
> 
> Then, I tried making that same process work on CentOS 7.  I
> ran into some issues, because the c7 kernel doesn't include
> HFSPLUS support (which is needed by isohybrid - long story).

> I hacked around that by modifying some parts of pungi and lorax
> to remove the HFSPLUS requirement.  I am also exploring building
> the HFSPLUS kernel module, so I don't have to hack up pungi / lorax.
> 
> But back to my question to this list.  Are the pungi and lorax
> tools part of the official CentOS build process?  If so, then
> I assume there must be customized version of them, given the
> problems I saw with HFSPLUS.

As I said, no. They're not used for the install isos currently.

> 
> If different tools are used instead of pungi / lorax, then what
> are those tools?  Are they documented?  Can I help with the
> documentation of them?


As I said, the install media is currently done via mkisofs. I don't
believe it's currently documented. The comps data is on git.centos.org,
along with the kickstarts for the live media.

You're certainly welcome to create documentation. If you request access
on the -docs list with your proposal, the people who oversee wiki access
will work with you.



-- 
Jim Perrin
The CentOS Project | http://www.centos.org
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