Current Series Release Notes

17.0.0.0rc1-6

Prelude

The OpenStack 2026.2 (Watcher 17.0.0) release advances Watcher’s modernization efforts, delivering a major milestone in the eventlet removal initiative, broader adoption of openstacksdk, more accurate cluster modelling, and stronger security defaults. This release focuses on making Watcher deployments more maintainable, more correct in their optimization decisions, and safer by default.

This release marks a turning point in the eventlet removal initiative: all Watcher services (API, Decision Engine, and Applier) now run in native threading mode by default. Eventlet, previously the default concurrency library, is now deprecated and will be removed in a future release.

The migration from legacy per-service clients to openstacksdk continues across the codebase. Building on the novaclient migration from the previous release, the Cinder, Keystone, and Placement integrations now use openstacksdk, removing the python-cinderclient and python-keystoneclient dependencies and aligning all integrations on OpenStack’s standard client library.

Optimization decisions are now more accurate and better aligned with Nova’s placement constraints. The vm_workload_consolidation strategy enforces allocation-based capacity checks in addition to utilization-based checks, producing more conservative and correct migration plans. Local disk accounting has been improved for boot-from-volume instances and flavors with ephemeral or swap devices, preventing valid destination hosts from being wrongly rejected. Compute scope availability_zones filtering now correctly limits audits to the specified zones.

Reliability of the cluster data model has been significantly hardened. A reentrant deadlock affecting the compute, storage, and baremetal models was fixed and a race condition that could silently lose model updates during periodic synchronization has been resolved. A lazily-populated per-node allocation cache further improves performance by avoiding redundant iterations when computing node resource usage.

New feature capabilities include support for default_parameters on audit templates (API microversion 1.7), allowing operators to pre-configure strategy parameter values directly on a template so that audits inherit them automatically. The action catalog also grows with two new actions: delete, which permanently removes a server instance and its associated resources, and shelve, which frees a host’s vCPU and RAM while preserving the instance data.

Finally, this release strengthens security defaults. Policy enforcement was added to the webhook trigger endpoint, requiring appropriate privileges to trigger event-driven audits, and service debug logging was hardened so the messaging transport URL is no longer written to logs, avoiding accidental exposure of embedded credentials.

Upgrade Notes

• Watcher now requires Python 3.11 or newer. The last release of Watcher to support Python 3.10 was 2026.1. Ensure Python 3.11 or newer is available before upgrading.

17.0.0.0rc1

New Features

• Added two new actions: delete and shelve.

  The delete action permanently removes a server instance and all its associated resources via the Nova API. It is automatically skipped when the target instance does not exist. Deletion cannot be reverted.

  The shelve action shelves a server instance via the Nova API, freeing compute resources (vCPU and RAM) on the host while preserving the instance data. It is automatically skipped when the target instance does not exist or is already in SHELVED or SHELVED_OFFLOADED state. The action accepts both states as valid postconditions, since Nova may offload the instance immediately depending on the backend storage.