The Greytower Project has implemented the Shoal GMS framework (Shoal Home Page) that enables the connectors to establish and maintain a communication channel to enable connector pairs to communicate and exchanges status and event notification. The clustering communication allows for the failure detection of any of the following components:

• Novell eDirectory
• Novell Identity Manager
• Grey Tower Connector

Automatic Failover and recovery services are managed by designating a node as a primary or secondary node.

 

• Primary Node

  The Primary node is considered to be the only active connector on startup. This node is responsible initially processing transaction from the specified queue or topic

• Secondary Node

 The secondary nodes is designed to be actively running but will not process messages unless it detects a failure in the primary node.

Grey Tower Clustering Example 
The Clustering example below example of how the clustering approach works. The below example assume there has been a failure affecting the primary node of the Grey Tower Connector pair. Once the Failure has been detected by the primary node dropping out of the cluster communication channel the secondary Node activate and starts processing the transactions from the queue.