While investigating OpenstackAPIResponse I noticed this in the nova-api logs:

2026-04-14 18:44:04.040 2557605 ERROR nova.api.openstack.wsgi PermissionError: [Errno 13] Permission denied: '/dev/shm/cloudcontrol1011_uwsgi_qmanager'

And increased API latencies on 1006/1011 but not 1007 where indeed that message is not present. Digging a little into what that file does turns out it is uwsgi shared memory file, which might end up shared between different uwsgi processes. The end result is a race to write that unique file name, and in this case nova lost the race.

The fix is to provide openstack with a service name for the queue manager to use and thus not have the filenames clash