Foglight 5.9.4 - High Availability Field Guide

You can change the cluster multicast port that is used when Foglight® is running in High Availability (HA) mode. This port is used by members of an HA cluster to communicate with each other. The primary and secondary Management Servers within each HA partition must be configured to use the same cluster multicast port.

If you plan to have multiple HA partitions on the same sub-network, configure a different cluster multicast port for each HA partition on the sub-network.

To change the cluster multicast port:

Stop the primary and secondary Management Servers that are part of the HA cluster.

Open the file <foglight_home>/config/server.config on each machine hosting a Management Server that is part of the HA cluster.

Set the parameter server.cluster.mcast_port to the desired value in these files.


	IMPORTANT: Ensure that the primary server and secondary servers within each HA partition are configured to use the same cluster multicast port.

Save the server.config files.

Restart the Management Servers.


	CAUTION: Errors can occur if servers that are not part of the same HA partition are configured to multicast on the same port on the same sub-network as the HA partition. For more information, see Troubleshooting FAQ.

Important considerations for configuring HA over WAN

Although HA outside of a single subnet (that is, across a WAN) is a supported configuration, it is important to first understand the performance and reliability implications of using this configuration.

Before distributing a Foglight® HA installation across data centers, consider the following:

•

WAN networks typically have lower bandwidth than LAN networks. Low bandwith and network congestion can lead to false failovers.

•

If the Foglight database is not distributed across data centers, one (or more) of the HA nodes must access the shared database remotely. This may cause poor performance.

•

If the Foglight database is not distributed across data centers, an outage in the data center that hosts the shared database results in total failure of the cluster.

For more information, see Troubleshooting FAQ , and Tuning connection issues in HA implementations .

Security considerations for HA configuration

JGroups provides the ENCRYPT class with the capability of encryption and decryption communications at any layer, without the need for a coordinator. For more information about the JGroups ENCRYPT class, visit the JGroups website. The Foglight Management Server adopts the option of configuring a secretKey in a keystore to secure the HA mode. This security implementation is specified by the following lines in the <foglight_home>/config/jgroups-config.xml file.

<UDP..../>

<ENCRYPT

encrypt_entire_message="true"

key_store_name="foglight.ha.keystore"

store_password="foglightha"

key_password="foglightha"

alias="foglightha"

</config>