Schedule job executes twice on cluster

Question

We are using Cron4j java scheduler for scheduling jobs which execute every night. Now, when this same web application is deployed(Tomcat) on cluster(2 nodes) at the client's site the jobs run twice. Is there any way to avoid this problem?

Answer 1

I believe the only way of doing this would be to use some external shared state, like in a database for example, to provide some locking.