.. _controlcenter_userguide_consumers:

Manage |ak| Consumers Using |c3-short| for |cp|
===============================================

.. meta::
  :title: Consumers in Confluent Control Center
  :description: This document describes monitoring consumer groups 
                using the Confluent Control Center user interface.
  :keywords: Confluent Control Center, consumers, consumer groups, consumer lag,
             total messages behind, consumer lag alert, percentage messages consumed,
             end-to-end latency

The Consumers menu provides a view of all consumer groups for all topics in a 
cluster. From the consumer pages, you can:

- View all consumer groups for a cluster in the :ref:`c3_all_consumers_groups`
- :ref:`View consumer lag <c3-cg-view-consumer-lag>` across all topics in a cluster
- View :ref:`consumption metric <c3_cg_view_consumption>` for a consumer group
- :ref:`Set up consumer group alerts <consumergroup_triggers>`

.. tip:: Consumer Lag for an individual topic can be accessed from 
         the :ref:`Topics <c3_view_topic_consumer_lag>` menu.

.. important:: 
               The Consumers feature is enabled by default using an Access Control setting
               in the |c3-short| properties files. See :ref:`c3_enable_disable_consumers`.
               If :ref:`RBAC <controlcenter_security_rbac>` is enabled for |c3-short|, the 
               resources you can access are determined by your
               assigned role or roles and their corresponding privileges.

.. note that a feature flag was put on this because the producers half is still coming in a subsequent release. 

.. _c3_all_consumers_groups:

All consumer groups page
------------------------

Use the All consumer groups page to:

- View all consumer groups for a cluster
- Search for a consumer group by its ID
- View the number of consumers and number of source topics for each consumer group
- View details such as :ref:`Consumer Lag <c3-cg-view-consumer-lag>` and
  :ref:`Consumption metrics <c3_cg_view_consumption>` for a consumer group
- Set up a pre-populated alert for :ref:`Consumer Lag <consumer_lag_trigger>`


**To access the All consumer groups page:**

#. Select a cluster from the navigation bar and click the **Consumers** menu.

   .. figure:: /images/c3-all-consumer-groups-page.png
      :width: 600px
      :alt: All consumer groups page

.. _c3-cg-view-consumer-lag:

View consumer lag details for a consumer group
----------------------------------------------

#. From the All consumer groups page, click the ID for your desired Consumer Group.
   Consumer lag details are displayed, including:

   - Total messages behind and the measured interval.
   - All consumers in the group.
   - A visualization of lag. The **Max lag / consumer** graph displays a
     pin point of each partition in the topic.
     

   .. figure:: /images/c3-consumers-cg-clag.png
        :width: 600px
        :alt: Consumer lag

#. To view details for a particular point on the graph, click its pin. View the 
   Consumer, Partition, Current offset, and Messages behind for that 
   particular point.

   .. figure:: /images/c3-consumers-cg-clag-point-details.png
      :scale: 80%
      :alt: consumer lag pin details


.. _c3_cg_view_consumption:

View consumption details for a consumer group
---------------------------------------------

View the percentage (%) of messages consumed and the end-to-end latency key 
metrics by a selected timeline.

.. note:: The consumption charts are only populated if there are Confluent 
          Monitoring Interceptors that are set up correctly. 
          For instructions, see :ref:`controlcenter_clients`.

#. From the :ref:`All consumer groups <c3_all_consumers_groups>` page, click 
   the ID for your desired Consumer Group.

#. Click the **Consumption** tab. The streams monitoring metrics are displayed 
   for the default timeframe (last 4 hours).

   .. figure:: /images/c3-consumer-consumption-page.png
      :width: 600px
      :alt: Consumer groups Consumption page

#. Select a timeframe from the menu and click **Apply**.

   .. figure:: /images/c3-timeframe-selector.png
      :scale: 50%
      :alt: Timeframe selector

      Timeframe selector 

   .. include:: includes/c3-time-range-selector.rst

#. Select the End-to-end latency metric you want to view:

   - average (ms)
   - minimum (ms)
   - maximum (ms)
   - total (ms)

   .. figure:: /images/c3-cg-latency-temp.png
      :scale: 80%
      :alt: End-to-end latency metric selector

   .. tip:: You can set up :ref:`alerts <consumergroup_triggers>` for average 
            and maximum latency values.

.. _c3_cg_context_alert:

Set up an alert for a consumer group
------------------------------------

You can set alerts from the Consumer lag page. These options pre-populate most of 
the consumer group trigger fields.

On the Consumer lag page, click **Set up an alert**.

.. figure:: /images/c3-consumers-cg-clag.png
   :scale: 50%

For more details, see :ref:`Consumer lag trigger <consumer_lag_trigger>`.


.. _c3_enable_disable_consumers:

Enabling and disabling the Consumers feature
--------------------------------------------

The Consumers 
feature for viewing details for consumer lag and consumption in consumer groups 
is enabled by default. The feature can be disabled by setting the 
``confluent.controlcenter.consumers.view.enable`` option
in the appropriate |c3-short| properties file 
to ``false``.  After disabling the
feature, the Consumer submenu in the Cluster navigation 
is no longer visible in the |c3-short| UI.

.. important:: If :ref:`RBAC <controlcenter_security_rbac>` is enabled for |c3-short|, 
               it takes precedence over Access Control settings.

To disable the Consumers feature in |c3-short|:

#. Set the ``confluent.controlcenter.consumers.view.enable`` option in 
   your ``control-center.properties`` file to ``false``.

   .. code:: bash

      ...
      confluent.controlcenter.consumers.view.enable=false
      ...

   .. note:: Make the change in the appropriate |c3-short| properties files configured for your 
             environments, including ``control-center-dev.properties`` or ``control-center-production.properties``. The 
             properties files are located in ``/path-to-confluent/etc/confluent-control-center/``. For
             more information, see :ref:`c3_properties_files`.

#. Restart |c3-short| and pass in the properties file for the configuration to take effect.

   - Local (dev) environment:

     .. important:: Do not use :confluent-cli:`confluent local|command-reference/local/index.html` for production use.

     .. sourcecode:: bash

        confluent local services control-center stop
        confluent local services control-center start --config ../etc/confluent-control-center/control-center.properties


   - Production environment:

     .. sourcecode:: bash

       ./bin/control-center-stop
       ./bin/control-center-start ../etc/confluent-control-center/control-center.properties

To enable the feature again, set the option back to ``true`` and restart 
|c3-short| with the updated properties file.