Description of problem:

With OSP11 the default for notification_format is both:

# Specifies which notification format shall be used by nova.
#
# The default value is fine for most deployments and rarely needs to be changed.
# This value can be set to 'versioned' once the infrastructure moves closer to
# consuming the newer format of notifications. After this occurs, this option
# will be removed (possibly in the "P" release).
#
# Possible values:
# * unversioned: Only the legacy unversioned notifications are emitted.
# * versioned: Only the new versioned notifications are emitted.
# * both: Both the legacy unversioned and the new versioned notifications are
#   emitted. (Default)
#
# The list of versioned notifications is visible in
# http://docs.openstack.org/developer/nova/notifications.html
#  (string value)
# Allowed values: unversioned, versioned, both
# Deprecated group;name - DEFAULT;notification_format
#notification_format=both

As a result messages get sent to both unversioned and versioned queues, but there is no consumer for the versioned_notifications queues. As a result they grow up slowly:

# rabbitmqctl list_queues name consumers messages| grep notifications
notifications.error     3       0
notifications.warn      3       0
notifications.debug     3       0
notifications.critical  3       0
notifications.sample    3       0
notifications.audit     3       0
versioned_notifications.info    0       26
notifications.info      3       0

For now notification_format should be set to unversioned as default on controllers and computes.

Version-Release number of selected component (if applicable):


How reproducible:
always

Steps to Reproduce:
1. install OSP11
2. start / stop some instances
3. versioned_notifications.info start to grow and there is no consumer

Actual results:


Expected results:


Additional info:

Could be done like this using ExtraConfig sections until the default changed.
    ControllerExtraConfig:
        nova::config::nova_config:
            notifications/notification_format:
                value: 'unversioned'
    NovaComputeExtraConfig:
        nova::config::nova_config:
            notifications/notification_format:
                value: 'unversioned'