---
features:
  - |
    The default concurrency mode is now switched from eventlet to native
    threading for nova-scheduler, nova-api, and nova-metadata services.
    The concurrency mode can still be switched back to eventlet if needed
    per service. Please read the
    `concurrency <https://docs.openstack.org/nova/latest/admin/concurrency.html>`__
    guide for more details.
upgrade:
  - |
    When you are upgrading to 2026.1 (Gazpacho) or newer the default
    configuration of nova-scheduler, nova-api, and nova-metadata services
    change to run these services with native threading mode by default
    instead of the legacy eventlet mode. We recommend to decouple the
    upgrade from the concurrency mode change to reduce the risk of issues.
    To do that either test the native threading mode of these services already
    in 2025.2 (Flamingo) or ensure that your service configuration is
    explicitly using the eventlet mode before you upgrade and only change to
    threading mode after the upgrade was successful. Please read the
    `concurrency <https://docs.openstack.org/nova/latest/admin/concurrency.html>`__
    guide for more details on how to configure the mode.
