Configure RabbitMQ
==================

Reduce startup time
-------------------

Before startup, each RabbitMQ pod executes a sleep command to prevent negative DNS caching results which can cause
problems with inter node communication for stream queues during restarts of RabbitMQ.

If you are working in a productive environment, this should only be done if the the DNS cache TTL of the Kubernetes DNS server is changed first.
Afterwards, the sleep duration can be overwritten by setting ``messageQueue.dnsCacheTTL`` inside the OpenStack manifest accordingly.

Inside development clusters it is fine to set the value 0 without adjusting the DNS server, just expect to encounter some error messages concerning stream queues.

Set requests and limits for RabbitMQ
------------------------------------

You can set CPU and Memory requests and limits for the AMQPServers like for every other Kubernetes workload.

.. note::

    The requests and limits are used to set some RabbitMQ config options:
    ``total_memory_available_override_value`` and ``default_worker_pool_size``

The config option ``total_memory_available_override_value`` is calculated by
using the Memory limits minus some headroom.

The option ``default_worker_pool_size`` is set based on CPU requests and only
if there are no requests, the CPU limits are used instead. The request(or
limit) is rounded down to a full CPU and used as worker count, minimum is one
worker.
This is because it's not recommended to use CPU limits, but if you do, the MQ
config should still respect that.

.. important::
    This means, that the erlang Process of RabbitMQ will only use as much cores
    as defined in the CPU requests, also you have a much higher limit set.

Still the container may use more CPU, as there are other processes that also
need some resources.

Override images
---------------

If you want to use custom images for an ``AMQPServer``, do so by adding a dictionary to ``.spec.imageOverrides``
with the pinned versions as keys and the image overrides as values. For upgrades, you have to
include every supported minor version from your current version up to the target version.
These overrides take precedence over the infra operator's ``YAOOK_OP_VERSIONS_OVERRIDE``.
Use at your own risk.

.. code-block:: yaml

    apiVersion: infra.yaook.cloud/v1
    kind: AMQPServer
    name: "sample-amqp"
    spec:
        imageOverrides:
            library/rabbitmq:3.13: custom-url/rabbitmq:v3.13
            library/rabbitmq:4.1: custom-url/rabbitmq:v4.1
            library/rabbitmq:4.2: custom-url/rabbitmq:v4.2
        ...

Using ``.spec.imageRef`` to override images is out of support and the setting will be removed in the
future.

If the AMQPServer was not created by another operator, you can migrate from ``imageRef`` to ``targetRelease``
by adding the ``imageOverrides`` without removing ``.spec.imageRef`` and waiting until the infra operator reconciled the AMQPServer.
To upgrade it, remove ``.spec.imageRef`` and specify the targetRelease afterwards. Currently, ``4.2`` is the latest supported release.

Disable quorum queue limits
---------------------------

.. warning::

    Disabling the limit is discouraged.

By default, Yaook will limit the size of each quorum queue to 5% of the total available disk space. This ensures that other queues are
still usable in case of a broken consumer or a misconfiguration. Disabling the limit increases
the timespan until issues occur, but the AMQPServer will become entirely unusable once the limit of the PVC is reached.

To disable the limit, add the following configuration:

.. code-block:: yaml

    apiVersion: infra.yaook.cloud/v1
    kind: AMQPServer
    name: "sample-amqp"
    spec:
        enableQueueSizeLimit: false
        ...


RabbitMQ exporter configuration
-------------------------------

The RabbitMQ exporter configuration can be modified inside ``.spec.messageQueue.exporterConfig`` of the
OpenStack k8s manifest, or if you are using a standalone AMQPServer, inside ``.spec.exporterConfig``.

============================================= ====== ========================================================================================================================================================================
Configuration value                           Type   Description
============================================= ====== ========================================================================================================================================================================
``logLevel="INFO"``                           string Supported values: "DEBUG", "INFO", "WARN", "ERROR"
``accumulatingMessagesThreshold=50``          int    Threshold for the number of messages inside a queue used by the metric ``rabbitmq_quorum_queue_accumulating_messages_count``
``accumulatingMessagesCriticalThreshold=500`` int    Threshold for the number of messages inside a queue used by the metric ``rabbitmq_quorum_queue_accumulating_messages_critical_count``
``scrapeInterval=60``                         int    Scraping interval in seconds. See the `RabbitMQ documentation <https://www.rabbitmq.com/docs/prometheus#metric-collection-and-scraping-intervals>`_ for more information
``httpTimeout=10``                            int    Timeout in seconds for requests to the RabbitMQ management API
============================================= ====== ========================================================================================================================================================================