JMS Bridges in High Availability (HA) Broker Clusters

Message Queue supports JMS bridges in HA broker clusters, but some special constraints apply due to the inherent nature of HA broker clusters:

• Each JMS bridge must have a name that is unique across all the JMS bridges in all the brokers in the cluster.

• Each JMS bridge must have the same bridge configuration across all the brokers in the cluster.

• The imq.bridge.enabled broker property must have the same value across all brokers in the cluster.

• Before broker startup, the imq.bridge.activelist broker property for each broker lists only those JMS bridges that are to be owned by that broker.

To ensure that bridges in the cluster have the same configuration across all brokers in the cluster, all bridge-related broker properties except for imq.bridge.activelist should be specified in the centralized cluster properties file defined by the imq.cluster.url broker property.

A table in the cluster's HA store is used to maintain a consistent record of JMS bridge ownership by the brokers in the cluster.

During broker startup, the JMS bridge service compares the broker's imq.bridge.activelist property value to this table's entries before starting any JMS bridges, with the following consequences:

• If a JMS bridge named in imq.bridge.activelist does not appear in the table, it is added to the table and associated with the broker.

• If a JMS bridge name in imq.bridge.activelist does appear in the table, and the table entry already associates the bridge with a different broker, the bridge name is removed from imq.bridge.activelist.

• If an entry in the table associates a JMS bridge with the broker, and that bridge's name is not in imq.bridge.activelist, the bridge name is added to imq.bridge.activelist.