Up until now, qemu-kvm has had a dependency on the qemu-block-curl plugin, which allows qemu guests to use http/https network locations as a disk source. However, in rhel 9, this dependency is being removed from qemu-kvm, which results in issues such as bug #2014229.

The long-term solution is to switch to using the more featureful and maintained nbdkit curl plugin (https://libguestfs.org/nbdkit-curl-plugin.1.html) within libvirt.

From an email from Rich:

It would need to instead run an nbdkit subprocess first, eg:

nbdkit -U /tmp/randomly-named-sock --exit-with-parent -f -r \
--pidfile /tmp/randomly-named-file \
curl http://foo protocols=http,https,ftp,ftps &

1. wait for pidfile to get created

1. pass nbd:unix:/tmp/randomly-named-sock as qemu parameter
2. or:
3. <disk type='network' device='disk'>
4. <driver name='qemu'/>
5. <source protocol='nbd'>
6. <host transport='unix' socket='/tmp/randomly-named-sock'/>
7. </source>
8. <target dev='vda' bus='virtio'/>
9. </disk>

1. wait for qemu then:
   kill `cat /tmp/randomly-named-file`
   rm /tmp/randomly-named-sock

(or nbdkit will clean itself up because of --exit-with-parent)