Context CDROM type not BLOCK when SYSTEM DS DISK_TYPE=block

[atodorov-storpool]

Description
When the SYSTEM datastore is configured with DISK_TYPE=block, the contextualization CDROM, which is managed entirely in the SYSTEM DS context and is no more or less a "special" volatile disk(right?), has type=file in the generated domain XML. The recent versions of qemu-kvm iaremore restrictive regarding the data provided so it is blocking the deployment of a VM with such a discrepancy in the definition.

To Reproduce

• configure a SYSTEM datastore to provide block devices for all VM disks, with DISK_TYPE=block
• define the VM with a Volatile disk
• try to instantiate a VM with context on a host with relatively recent qemu-kvm, like ubuntu 24.04

The deployment will fail with an error like 'file' driver requires '/var/lib/one//datastores/0/0/disk.1' to be a regular file

Note: the volatile disk is properly defined as a disk device with type=block.

Expected behavior
All disk devices in the system datastore should have the same disk type, as the one defined in the DISK_TYPE attribute of the System datastore.

Details

• Affected Component: [core]
• Hypervisor: [KVM]
• Version: [6.9 and below]

Additional context
It is relatively easy to workaround but then we hit an omission in the vmm/reconfigure script, will open a separate ticket for it as it is affecting the VMM_MAD, not the core (and please allow me to mention again that it should be much better if the VMM_MAD wad doing the domain XML instead of the core...)

Progress Status

• Code committed
• Testing - QA
• Documentation (Release notes - resolved issues, compatibility, known issues)