Configure the master with server.conf

Prerequisites

Before reading this topic, see Configure the indexer cluster with server.conf. It discusses configuration issues that are common to all cluster node types.

Enable the master node

The following example shows the basic settings that you configure when enabling a master node. Unless otherwise noted, the settings are required. The configuration attributes correspond to fields on the Enable clustering page of Splunk Web.

[clustering]
mode = master
replication_factor = 4
search_factor = 3
pass4SymmKey = whatever
cluster_label = cluster1

This example specifies that:

• the instance is a cluster master node.
• the cluster's replication factor is 4.
• the cluster's search factor is 3.
• the security key is "whatever". All nodes in the cluster use the same security key. See Configure the security key.
• the cluster label is "cluster1." The optional cluster label is useful for identifying the cluster in the monitoring console. See Set cluster labels in Monitoring Splunk Enterprise. You set this attribute on the master node only.

Important: When the master starts up for the first time, it will block indexing on the peers until you enable and restart the full replication factor number of peers. Do not restart the master while it is waiting for the peers to join the cluster. If you do, you will need to restart the peers a second time.

Note: When you enable the master node in Splunk Web, the resulting server.conf stanza includes attributes only for non-default values. For example, if you accept the default replication factor of 3 and do not enter a new value for it, the resulting stanza does not include the replication_factor attribute.

Edit the master settings

You can change these settings later, if necessary. For example, to change the cluster's security key, you edit the pass4SymmKey value on each node.

For details on all cluster attributes, including some advanced ones that rarely require editing, read the server.conf specification.