openstack/watcher — 2026-08-22

Testing and simulation. The largest change of the week lands Nova and Placement emulators together with functional tests covering the host_maintenance strategy — roughly 4,000 lines of new fixtures aimed at exercising strategies end-to-end without a real cloud. Alongside that, the vm_workload_consolidation strategy gained allocation-based capacity checks against Placement, tightening the accounting used when packing workloads onto fewer hosts (993088).

Data source caching. A new MetricDataCache was introduced and wired into DataSourceBase, giving strategies a shared caching layer over metric lookups instead of re-querying the backend for each decision.

API surface. The webhook trigger endpoint now enforces policy, and the same fix was carried across four branches as backports. On the read side, /v1/audits/detail learned to filter by strategy, making it easier to slice audit listings by the strategy that produced them.

Stability. A corruption bug in ComputeScope.allowed_nodes was fixed, where the scoped node set could be mutated across evaluations. A stray LOG.warn self-check was also dropped from the tree.