2017-03-21 15:06:39,659 | ERROR | eChangeHandler-0 | LockManager | 351 - org.opendaylight.genius.lockmanager-impl - 0.2.0.SNAPSHOT | Unable to acquire lock, try 1
java.util.concurrent.ExecutionException: OptimisticLockFailedException
As per definition in Logging Best Practices, this should be a WARN, as there is a retry mechanism in place.
I am not familiar with the design of the lock manager, but it seems it could be using EntityOwnershipService, which already provides cluster-wide exclusive locking.
If the exceptions are direct result of application design and retries are expected, the message should be lowered to debug.