Re: Support for Debian on OpenShift Virtualization for s390x
Hi
On Wed, Jul 23, 2025 at 02:34:11PM +0000, Nestor Acuna Blanco wrote:
> I am part of an IBM team working to enable Debian by default in OpenShift Virtualization for the s390x architecture. To achieve this, we are developing containerdisks<https://quay.io/organization/containerdisks> based on the cloud images of the relevant Linux distributions. However, for the bookworm release, we have noticed that there are currently no s390x images available<https://cloud.debian.org/images/cloud/bookworm/latest/>.
> My question is: what do you need for the creation of such an image, and how can we support you in this process?
No-one ever provided a config for s390x. We know that s390x is not well
maintained in Debian and every release again ponder if we should just
drop it, this port is just so far from everything a random user got
access to. To be exact, I started a non-booting config already:
https://salsa.debian.org/cloud-team/debian-cloud-images/-/merge_requests/457
I think the only real problem is: We need to be able to setup a
bootloader for our image. However, we need to do that without access to
a filesystem or even block device and while using a random x86 machine.
While this exact code is not active yet, we intend to generate our
images in the future using "mkfs.ext4" to load files, without ever
mounting this filesystem or setting up loop devices.
The zipl binary is not able to do that for us. It requires to write to
a mounted filesystem and then to lookup the physical location of the
bootmap. Also all the boot code and structures to read the boot code
are hidden inside the zipl binary. Not to mention that there are three
different loaders, where SCSI is the relevant here, but it will not boot
from CCW disks.
What would really help, not only us:
- Allow zipl to write the bootmap into a separate partition (split it
into two, to allow semi atomic updates).
- Make sure zipl does not need block devices.
Or: document the structures apropriatly, so we can write the boot code
and the boot map with ever using zipl.
Regards,
Bastian
--
Knowledge, sir, should be free to all!
-- Harry Mudd, "I, Mudd", stardate 4513.3
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