Hazelcast is a third-party technology that is used when Confluence Data Center is installed in a cluster configuration. It is used both by Confluence and Synchrony. 

Hazelcast can be configured to use different ports by passing in Java System Properties. See Configuring System Properties to find out the various ways system properties can be set for your site. 

Hazelcast port for Confluence

The Hazelcast port for Confluence can be changed by setting the confluence.cluster.hazelcast.listenPort system property. The way this property is set is by adding the confluence.cluster.hazelcast.listenPort property in the  <installation-directory>/bin/setenv.sh file's CATALINA_OPTS= section as such:

CATALINA_OPTS="-Dconfluence.cluster.hazelcast.listenPort=5801 ${CATALINA_OPTS}"

If the confluence.cluster.hazelcast.listenPort system property is not present, the Hazelcast port for Confluence will default to port 5801. 

Hazelcast port for Synchrony

The Hazelcast port for Synchrony can be changed by setting the cluster.listen.port system property.  The way this property is passed to Synchrony depends on how you run Synchrony and the Confluence version.

• If you run a Synchrony standalone cluster, the Hazelcast port is customized by adding the cluster.listen.port  property in the start-synchrony.sh  or start-synchrony.bat  script.
  Linux

  OPTIONAL_OVERRIDES="-Dcluster.listen.port=5701"

  Windows

  set OPTIONAL_OVERRIDES=-Dcluster.listen.port=5701

• If you use Confluence managed Synchrony, the Hazelcast port is customized by:
  • For Confluence 9.1.0+, add the cluster.listen.port  property to the main Confluence JVM flags as per Configuring System Properties which will flow onto managed Synchrony process. e.g. On Linux:

    CATALINA_OPTS="-Dcluster.listen.port=5701 ${CATALINA_OPTS}"

  • For versions older than Confluence 9.1.0, add the cluster.listen.port  property to the synchrony-args.properties  file. 

    cluster.listen.port=5701

If the cluster.listen.port property is not present, the Hazelcast port for Synchrony will default to port 5701.