---
other:
  - |
    This release includes work in progress support for Keystone's unified
    limits. This should not be used in production. It is included so we can
    collect early feedback from operators around the performance of the new
    limits system. There is currently no way to export your existing quotas
    and import them into Keystone. There is also no proxy API to allow you
    to update unified limits via Nova APIs. All the update APIs behave as if
    you are using the noop driver when the unified limits quota driver is
    configured.

    When you enable unified limits, those are configured in Keystone against
    the Nova endpoint, using the names:

    * ``class:VCPU``
    * ``servers``
    * ``class:MEMORY_MB``
    * ``server_metadata_items``
    * ``server_injected_files``
    * ``server_injected_file_content_bytes``
    * ``server_injected_file_path_bytes``
    * ``server_key_pairs``
    * ``server_groups``
    * ``server_group_members``

    All other resources classes requested via flavors are also now supported as
    unified limits. Note that nova configuration is ignored, as the default
    limits come from the limits registered for the Nova endpoint in Keystone.

    All previous quotas other than ``cores``, ``instances`` and ``ram`` are
    still enforced, but the limit can only be changed globally in Keystone as
    registered limits. There are no per project or per user overrides
    possible.

    Work in progress support for Keystone's unified limits
    can be enabled via ``[quota]/driver=nova.quota.UnifiedLimitsDriver``

    A config option ``[workarounds]unified_limits_count_pcpu_as_vcpu`` is
    available for operators who require the legacy quota usage behavior where
    VCPU = VCPU + PCPU. Note that if ``PCPU`` is specified in the flavor
    explicitly, it will be expected to have its own unified limit registered
    and PCPU usage will *not* be merged into VCPU usage.

Add reno for unified limits
Add reno for unified limits

This first version should be considered as a preview, that will become
more useable once more of the transition tooling has been implemented.

Given the massive change, it seems prudent to get as much of this into
operators hands as quickly as possible, so we can get some early
feedback.

blueprint unified-limits-nova

Change-Id: I80ccca500d1a2eb8f19b5843a0d0d337c583e104
