Documentation on how to change PCEP config for 3-node cluster is needed

Running Beryllium cluster with odl-integration-compatible-with-all installed on all nodes, there is possibility a node will end up in "server is unhealthy". Search for "resource-denied" in [0] and read onwards.

If this is not a Bug in PCEP code, it means 39-pcep-provider.xml contains data not suitable for cluster deployment. We (releng/builder or integration/test) can prepare different content for this file on each node, but we need a documentation from Bgpcep project, preferable as a wiki page.

This is beginning of the first exception in log:

2016-02-03 01:31:56,371 | WARN | lt-dispatcher-32 | ConcurrentDOMDataBroker | 143 - org.opendaylight.controller.sal-distributed-datastore - 1.3.0.SNAPSHOT | Tx: DOM-0 Error during phase CAN_COMMIT, starting Abort
OptimisticLockFailedException

{message=Optimistic lock failed., errorList=[RpcError [message=Optimistic lock failed., severity=ERROR, errorType=APPLICATION, tag=resource-denied, applicationTag=null, info=null, cause=org.opendaylight.yangtools.yang.data.api.schema.tree.ConflictingModificationAppliedException: Node was created by other transaction.]]}

at org.opendaylight.controller.cluster.datastore.SimpleShardDataTreeCohort.canCommit(SimpleShardDataTreeCohort.java:54)

[0] https://jenkins.opendaylight.org/releng/view/controller/job/controller-csit-3node-clustering-all-beryllium/108/consoleFull