title: How to have only a single instance of mdb (message driven bean ) in a clustered(2 nodes) environment
body: <p>We use JMS Queues in our application and the application is deployed on two nodes on a websphere cluster. 
  The JMS queue is created on cluster level in websphere. We are using  JMS message listener that gets invoked whenever there is a message in the queue.</p>
  
  <p>I want to know how many message listener instances exists in such cases when there are two nodes. 
  Currently We are observing the messages are processed simultaneously ie if two message are in queue they are picked right away instead of one after other. How to stop this issue.
  I want a sequential approach to process messages.Thanks </p>