.. _controlcenter_userguide_cluster_settings:

Cluster settings
================

You can view and edit cluster properties and broker configurations in the 
Cluster settings pages. When you click the Cluster settings submenu for a 
cluster, the Kafka tab appears by default. 

..  There is no landing page. See MMA-4463. Designs forthcoming. reinstate legacy content as apropos at that time. See 5.2 version of topic or this PR for deleted content.

.. _edit_cluster_name:

Edit a cluster name
-------------------

You can edit the cluster name and view the host details. The host field lock 
icon indicates it cannot be changed.

To change the cluster name:

#. Click the cluster from the cluster navigation bar.
#. Click the **Cluster settings** menu.
#. Edit the cluster name in **Cluster Name** field. The default cluster name is the 
   cluster GUID. Enter a human-friendly name for the cluster. The cluster name you enter here is not 
   exposed externally from |c3-short|.
#. Click **Save changes** to apply your changes.

   .. figure:: ../images/c3-cluster-settings-kafka.png
      :width: 600px


.. _view_broker_config:

View-only broker configuration
------------------------------

View the cluster broker configuration. 

.. note:: If broker configuration editing is :ref:`disabled<ff_c3_edit_broker_configs>`, the view is 
          read-only and the :ref:`Edit Settings<ff_c3_edit_broker_configs>` feature is not available.

.. important:: If :ref:`RBAC <controlcenter_security_rbac>` is enabled for |c3-short|, it takes 
               precedence over Access Control settings. The privileges associated
               with your assigned roles determine what you can view and access.

To view a broker configuration:

#. Click the cluster from the cluster navigation bar.

#. Click the **Cluster settings** menu.

#. Click the **Brokers** tab. A read-only view of the broker configuration is displayed. The
   Edit Settings button is not shown on the page.

.. _edit_broker_config:

Edit dynamic broker configuration settings
------------------------------------------

The dynamic broker configuration option is :ref:`enabled by
default <ff_c3_edit_broker_configs>`. The feature allows editing broker
configurations within |c3-short| that do not require a restart. Any
configuration option that has a ``per-broker`` or ``cluster-wide`` Dynamic
Update Mode can be edited. Any options designated as ``read-only`` for the
dynamic update mode requires a restart and cannot be edited dynamically.

For information about available broker configuration options, including the
dynamic update mode per option, see :ref:`cp-config-brokers`.

Legend:

- Green-filled bullet: Indicates non-default configuration options. An option
  had its value changed from the default.
- Empty-fill bullet: Indicates default configuration options.
- Asterisk*: Indicates a possible issue with configuration options 
  that have *n* different values* (asterisk) between brokers.

  .. important:: Review any brokers flagged with different configuration values to 
                 ensure they are all set as intended. In the example below, 
                 broker IDs are expected to be unique values.

  .. figure:: ../images/c3-broker-config-diff-values.png
      :scale: 80%

To edit the broker configuration:

#. Click the cluster from the cluster navigation bar.

#. Click the **Cluster settings** menu.

#. Click the **Brokers** tab.

#. To compare and edit settings for multiple brokers, select 
   two or more brokers in the broker IDs pane.

   .. figure:: ../images/c3-select-brokers-compare-temp.png
      :scale: 80%

   .. tip:: If you have a large number of brokers, use the **Deselect all**
            and **Select all** check boxes to quickly work with the brokers you want.

#. Click the **Hide settings set to default value** toggle to toggle it off and
   show all configuration options, including those options set to their
   default values:

   .. figure:: ../images/c3-view-settings.png
      :width: 600px

#. Click **Edit Settings**. The broker settings appear with edit icons:

   .. figure:: ../images/c3-broker-configs-edit.png
       :width: 600px

   - Hover over any option to view its description.
   - Click the edit icon to make changes to a configuration option.
   - Click **Set to Default** to reset an option back to its 
     original default. The bullet changes from green to empty.

   .. figure:: ../images/c3-broker-edit-icon-tip-default.png
       :width: 600px

#. Click **Save Settings**. Click **Discard Settings** to discard edits to settings.

To see examples of changing broker configurations dynamically using the |ak| command
line kafka-configs tool, see
:ref:`kafka_dyn_broker_config`.

.. _download_broker_config_settings:

Download broker configuration settings
--------------------------------------

#. Click the cluster from the cluster navigation bar.

#. Click the **Cluster settings** menu.

#. Click the **Brokers** tab.

#. Select a broker if there is more than one.

#. Click **Download**. A file that contains the broker configuration settings 
   is downloaded into your downloads directory
   in JSON file format. The filename is based on the 
   |ak| cluster ID.

   Example filename:  ``iKGixtHySCa0ANeH43pWHA.json``

   Example contents snippet:

   .. code:: bash

      {"0":{"entries":[{"name":"log.cleaner.min.compaction.lag.ms","value":"0","source":"DEFAULT_CONFIG","synonyms":[{"name":"log.cleaner.min.compaction.lag.ms","value":"0","source":"DEFAULT_CONFIG"}],"isReadOnly":false,"isSensitive":false},{"name":"offsets.topic.num.partitions","value":"50","source":"DEFAULT_CONFIG","synonyms":[{"name":"offsets.topic.num.partitions","value":"50","source":"DEFAULT_CONFIG"}],"isReadOnly":true,"isSensitive":false},{"name":"confluent.support.metrics.enable","value":null,"source":"STATIC_BROKER_CONFIG","synonyms" ...
   


.. _ff_c3_edit_broker_configs:

Enable and disable dynamic editing of broker configurations
-----------------------------------------------------------

The Dynamic Broker Configuration feature that allows editing settings without a
restart is enabled by default. The feature can be disabled in |c3-short| if an
organization does not want any users to access the feature. After disabling the
feature, the Edit Settings button in the Brokers tab in the |c3-short| UI
is no longer visible.

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

To disable the edit broker config settings feature in |c3-short|:

#. Set the ``confluent.controlcenter.broker.config.edit.enable`` option in your ``control-center.properties`` file to ``false``.

   .. code:: bash

      ...
      confluent.controlcenter.broker.config.edit.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/``.

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

   - Local (dev) environment:

     .. important:: Do not use :ref:`confluent_local` for production use.

     .. sourcecode:: bash

        confluent local stop --path <path-to-confluent>
        confluent local start --path <path-to-confluent> ../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.