openstack/nova — Week of 2026-07-11

Concurrency model. The largest change introduces a concurrency_backend config option for Nova services (review.opendev.org/c/openstack/nova/+/993760), letting operators select the underlying concurrency implementation, with a follow-up correcting the release name referenced by the new option. Related test-infrastructure work moves the Database and CellDatabases fixtures to file-backed SQLite with WAL in threading mode, and extends the same file-backed Placement SQLite approach to functional threading tests — laying groundwork for exercising Nova under the new backend.

Bug fixes. Two matching patches fix mutation of global config in the websocket proxy, landing on master and a stable branch. The API now returns 400 rather than a server error for invalid locked-memory properties, and QEMU_IMG_LIMITS process limits become configurable rather than hardcoded. A test-only fix addresses intermittent 409s in TestGracefulShutdown.

Elsewhere. The cyborg-tempest job is renamed to cyborg-tempest-py3.