Nodes and Clusters

Each node is an instance of Mediator running on an instance of Integration Server. When you configure each node of the system to communicate with the same CentraSite server, you create a cluster. A cluster is a group of nodes that monitors the same virtual service and sends events and metrics triggered by that virtual service to CentraSite.

Communication in a cluster is peer-based. In a peer-based cluster, any node in the cluster can perform processing tasks, including processing virtual service requests. However, nodes process messages differently depending on the task as follows:

When CentraSite deploys virtual service and consumer application data to Mediator, the load balancer selects the processing node.

When Mediator sends event notifications and metrics to CentraSite, the node that is the first available to process the message does so.

Note:

If communication between the cluster and CentraSite is disabled, then the cluster cannot report metrics. However, if you configured the cluster to report run-time event notifications to CentraSite over SNMP, these event notifications continues if the CentraSite SNMP destination is enabled and configured correctly. For more information about the role of the shared cache for deployment, see Deployment in a Cluster. For more information about the role of the shared cache for metric notification, see Metric and Event Notification in a Cluster.