.. _controlcenter_userguide_brokers:

#######
Brokers
#######

.. meta::
  :title: Monitor broker metrics in Confluent Control Center
  :description: This document describes monitoring brokers in Kafka clusters 
                using the Confluent Control Center user interface.
  :keywords: Confluent Control Center, brokers, production throughput,
             production request latency, failed production requests, consumption
             throughput, consumption request latency, failed consumption 
             requests, broker uptime, available brokers, active controllers, 
             ZooKeeper, partition replicas, in sync replicas, out of sync 
             replicas, under-replicated partitions, network pool usage, 
             request pool usage, disk usage


The Brokers feature provides a succinct view of essential |ak-tm| metrics 
for brokers in a cluster:

- Throughput for production and consumption
- Partitions and partition replica status
- Active controller and |zk-full| status
- Disk usage and distribution
- System metrics for network and request pool usage

.. _c3_brokers_overview_metrics:

*********************
Brokers overview page
*********************

The Brokers overview page conveys at a glance the health of 
brokers (nodes) in a |ak| cluster. View a summary of broker health and metrics.

To access the Brokers overview page, select a cluster from the 
navigation bar and click **Brokers** from the cluster submenu.

.. figure:: ../images/c3-brokers-overview.png
   :width: 600px

   Brokers overview

The clickable summary cards allow you to drill into detailed metrics charts for:

- :ref:`production <c3_brokers_production_metrics>`
- :ref:`consumption <c3_brokers_consumption_metrics>`
- :ref:`broker uptime <c3_broker_uptime_metrics>`
- :ref:`partition replicas <c3_partition_replicas_metrics>`
- :ref:`system network and request pool usage <c3_brokers_system_metrics>`
- :ref:`disk usage <c3_brokers_disk_metrics>`

To navigate back to the Brokers overview page after drilling 
into the :ref:`Metrics dashboard <c3-brokers-metrics>`, either click the
**Brokers** submenu again or click the **Brokers Overview >** breadcrumb at the 
top of the page.

The cards show a red sidebar for any issues that require operator attention.

.. figure:: ../images/c3-brokers-active-controller.png
   :scale: 50%

   Multiple active controllers issue

.. tip:: You can set alerts on many of these metrics, such as: production 
         request latency, :ref:`under-replicated partitions <URP_cluster_trigger>`, 
         out of sync replica count, :ref:`active controller count <AC_cluster_trigger>`, 
         |zk| status, and more. Send alerts action notifications though email, 
         Slack, or PagerDuty. For details, see :ref:`controlcenter_userguide_alerts`.

The Brokers table at the bottom of the page lists all brokers by ID. Use this
table to:

- Search for a broker by its ID.
- Sort a column by clicking in the column title cell.
- View throughput (bytes in and out per second) and latency (fetch and produce) 
  percentile metrics.


.. _c3-brokers-metrics:

********************
Brokers metrics page
********************

To access the Metrics page for brokers, click any summary card on the 
:ref:`c3_brokers_overview_metrics`. All metrics panels are conveniently 
located on one page. Clicking a particular card on the Brokers overview page
brings the relevant metrics panel into focus:

- :ref:`c3_brokers_production_metrics`
- :ref:`c3_brokers_consumption_metrics`
- :ref:`c3_broker_uptime_metrics`
- :ref:`c3_partition_replicas_metrics`
- :ref:`c3_brokers_system_metrics`
- :ref:`c3_brokers_disk_metrics`

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


.. _c3_brokers_metrics_select_timeframe:

Timeframe selector
==================

Click the timeframe selector to select the granularity for viewing data. 
The timeframe default is the last 4 hours for the current date.

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

   Timeframe selector

.. _c3_brokers_metrics_selector:

Filter brokers
==============

In a multiple broker environment, use the interactive broker selection controls 
to view the metrics charts for multiple brokers. Click **Deselect all** or 
**Select all**, or individually select each broker you want to 
view on the applicable charts.

.. figure:: ../images/c3-filter-brokers.png
   :scale: 80%

.. note:: Not applicable to 
          :ref:`Broker uptime panels <c3_broker_uptime_metrics>`.

.. _c3_customize_brokers_metrics_dash:

Customize the dashboard for brokers metrics
===========================================

Drag and drop to rearrange the order of the brokers metrics dashboard panels.

.. note:: The settings only persist across the same browser and computer.

#. Click **Customize Dashboard** on the Brokers Overview > Metrics page.

   .. figure:: ../images/c3-brokers-metrics-cust-dash.png
      :scale: 50%

#. Drag the panels into the order you want.

#. Click **Save**.

.. _c3_brokers_request_latency_selector:

Request latency selector
========================

Select a percentile from the menu for viewing production or consumption request 
latency.

.. figure:: ../images/c3-broker-request-latency-menu.png
   :scale: 50%

.. tip:: Click on a point of the line graph in the Request latency panels to 
         view details on Production or Consumption request latency.

.. _c3_brokers_inspect_cursor:

Inspection cursor
=================

Hover on any point in any chart graph line to view details for a specific 
point in time.

.. figure:: ../images/c3-broker-metrics-hover-details.png
   :scale: 50%

.. _c3_brokers_production_metrics:

Production metrics panel
========================

To access the Production metrics panel, click the **Production** summary card 
from the :ref:`c3_brokers_overview_metrics`.

The Production panel shows throughput, request latency, and
any failed production requests.

.. figure:: ../images/c3-brokers-metrics-prod-panel.png
   :scale: 50%

Click on a point of the line graph in the Request latency panel to view
details on Production request latency.

.. figure:: ../images/c3-production-request-latency.png
   :scale: 80%

   Production request latency

.. _c3_brokers_consumption_metrics:

Consumption metrics panel
=========================

To access the Consumption metrics panel, click the **Consumption** summary card 
from the :ref:`c3_brokers_overview_metrics`.

The Consumption panel shows throughput, request latency, and any failed 
consumption requests.

.. figure:: ../images/c3-brokers-metrics-consump-panel.png
   :scale: 50%

Click on a point of the line graph in the Request latency panel to view
details on Consumption request latency.

.. figure:: ../images/c3-consumption-request-latency.png
   :scale: 80%

   Consumption request latency


.. _c3_broker_uptime_metrics:

Broker uptime metrics panel
===========================

To access the Broker uptime panel, click the **Broker uptime** summary card from 
the :ref:`c3_brokers_overview_metrics`.

The charts show uptime for available brokers, active controllers, and |zk|.

.. figure:: ../images/c3-brokers-metrics-uptime-panel.png
   :scale: 50%

.. note:: Broker uptime metrics are cluster-wide, and do not apply to individual 
          brokers. The :ref:`Filter broker controls <c3_brokers_metrics_selector>`
          are not applicable to the Broker uptime panel.


.. _c3_partition_replicas_metrics:

Partition replicas metrics panel
================================

To access the Partition panel, click the **Partitions** summary card from the 
:ref:`c3_brokers_overview_metrics`.

The charts show the total number of partitions, in sync, out of sync, and 
under-replicated partitions.

.. figure:: ../images/c3-brokers-partition-replicas-panel.png
   :scale: 50%


.. _c3_brokers_system_metrics:

System usage panel
==================

To access the System panel, click the **System** summary card from 
the :ref:`c3_brokers_overview_metrics`.

The System panel shows network and request pool usage.

.. figure:: ../images/c3-brokers-metrics-system-panel.png
   :scale: 50%

.. _c3_brokers_disk_metrics:

Disk usage panel
================

To access the Disk panel, click the **Disk** summary card from 
the :ref:`c3_brokers_overview_metrics`.

The Disk panel shows maximum usage, minimum usage, and distribution.

.. figure:: ../images/c3-brokers-metrics-disk-panel.png
   :scale: 50%