[Libguestfs] Which ISO format/layout does virt-builder expect?

[Richard W.M. Jones]

On Thu, Dec 10, 2015 at 07:53:55PM +0000, Scott Gorton wrote:
> My build process creates a custom ISO image which is subsequently
> used to kickstart an Oracle X4-2 server using PXE.  The ISO is a
> minimal install and contains a suite of packages and customization
> scripts to properly configure our box during first boot.  The
> process works great for kickstarting baremetal machines as well as
> VMs created with virt-manager or vsphere.
>
> I'd like to be able to use virt-builder to build virtual images
> automatically (i.e., take our .ISO and generate a qcow2 of a
> properly installed system).  Unfortunately, virt-builder doesn't
> seem to like the format of my ISO image.  The tool dies during the
> "Setting passwords" step because it's attempting to create a temp
> file in /etc and my ISO doesn't have an /etc directory at this
> point.

ISOs are not modifiable by the Linux kernel :-(  So none of the tools
like guestfish, virt-customize etc etc can work on them.  It doesn't
matter what options you use, the problem is in the Linux ISO driver
(and possibly the ISO format -- I've no idea if it's plausible to
write a driver than can modify ISO).

For virt-p2v, we also need an ISO and a PXE image, and I would dearly
like to use virt-builder to create it.  I tried looking into ways to
build one using virt-builder, but it's a much harder problem than it
appears.

In summary, if you find a way, please let us know :-(

The virt-p2v scripts we have so far are:

https://github.com/libguestfs/libguestfs/blob/master/p2v/virt-p2v-make-disk.in
(documentation:
http://libguestfs.org/virt-p2v-make-disk.1.html)

https://github.com/libguestfs/libguestfs/blob/master/p2v/virt-p2v-make-kickstart.in
(documentation:
http://libguestfs.org/virt-p2v-make-kickstart.1.html)

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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