Create a new cluster topic

We can either convert an existing topic into a cluster topic, or create a new cluster topic. You do this by navigating to the topic properties, then specifying the name of the cluster that is to host this topic, and the cluster routing mechanism to use for publications on this topic.


Before starting

Create a cluster containing two or more queue managers, as described in Create a queue manager cluster.

The SYSTEM.BASE.TOPIC and SYSTEM.DEFAULT.TOPIC should not typically be used as cluster topics. This is because SYSTEM.BASE.TOPIC is present on all cluster queue managers, therefore it only affects the local queue manager unless it is modified on all queue managers to have a correctly functioning publish/subscribe cluster. The entire topic tree is also within a single cluster, preventing subsections of topic space being in a cluster, and making it harder to divide subsections of topic space into separate clusters. However, there are situations where it is necessary, such as IBM Integration BusCollective migration. For more information, see Publish/subscribe messaging.

There are also a number of reasons not to make SYSTEM.DEFAULT.TOPIC a cluster topic: it is present on all queue managers in a cluster, so it only affects the local queue manager, and all topics defined while it is a cluster topic also become cluster topics in the same cluster.


To create a new cluster topic in the IBM MQ Explorer Navigator view, complete the following steps:


Procedure

  1. Expand the cluster queue manager in which we want to create a new cluster topic.
  2. In the navigation pane, select Topics.

    A list of existing topics is displayed in the main pane.

  3. Either select an existing topic, or create a new topic.

    • To select an existing topic, double-click the topic in the main pane.
    • To create a new topic, right-click Topics in the navigation pane, then select New > Topic. For more information, see Create a new topic.

  4. In the properties pane, click Cluster to open the Cluster properties page.
  5. Type the name of the cluster we want the topic to belong to in the Cluster topic field.
  6. Optional: For Version 8.0 and later versions, select the routing mechanism from the Cluster route drop-down list. The choices are as follows:

      Direct
      Messages published on one queue manager are sent directly from that queue manager to every subscription on any other queue manager in the cluster.

      Topic host
      Messages published on one queue manager are sent from there to a queue manager that hosts the definition of the topic. That topic host queue manager routes the message on to every subscription on any other queue manager in the cluster.

  7. Click Apply to save the change.


Results

The topic has now become a cluster topic. Parent topic: Configure publish/subscribe for Version 7.0 and later queue managers


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