This section explains the possible scenarios when a message processor is run in a worker-manager cluster node. In such situations, only workers are required to process/serve client requests while managers are mainly required to carry out administration activities and synchronize the administrative information of the workers in the cluster. A message processor may be executed by one or more worker nodes.Usually, a message processor is executed by one worker node with the current ESB implementation. However, there can be scenarios where a message processor is simultaneously executed by
The following scenarios are possible when one or more message processors are run in a worker-manager cluster node.
Message processor execution by one node
When a system administrator starts starts the WSO2 ESB in a worker-manager cluster mode with the WSO2 Elastic Load Balancer, only one worker can run a given message processor by default. No manager can run the message processor in this scenario.
Message processor execution by a given/selected set of workers
In this scenario, a message processor can be simultaneously executed by more than one worker node in the cluster to optimise performance. The number of worker nodes that is allowed to execute the message processor at a given time can be controlled by specifying the required number in the message processor configuration as follows:
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<parameter name="member.count">2</parameter> |
All the configuration changes done to the message processor will take effect after the next ESB instance/cluster restart.
Shutting down a member with one or more message processors
When a worker node where on which one or more worker nodes message processors are running run is shut down by an administrator or due to a failure, those message processors are scheduled on the other members of can be transferred to other worker nodes in the cluster.