# Reg:ODL_Lithium_SR2_clustering_issues

Hi All,

I have a 3 node cluster set up and the cluster comes up fine with no issues.

But when I trigger my network discovery process most of the time any of the follower nodes gets the below exceptions spread across its karaf log and the MDSAL instance goes for a toss.

Let me know when the cluster (akka layer) gets into this state and let me know any important cluster configuration related parameters that shall aid me here to solve and get out of this.

Thanks for your time and assistance.

a)org.opendaylight.controller.md.sal.common.api.data.DataStoreUnavailableException: Could not find a leader for shard member-2-shard-default-operational. This typically happens when the system is coming up or recovering and a leader is being elected. Try again later. at org.opendaylight.controller.cluster.datastore.NoOpTransactionContext.readData(NoOpTransactionContext.java:76)[190:org.opendaylight.controller.sal-distributed-datastore:1.2.0.Lithium] ... 23 more d)Caused by: org.opendaylight.controller.cluster.datastore.exceptions.NoShardLeaderException: Could not find a leader for shard member-2-shard-default-operational. This typically happens when the system is coming up or recovering and a leader is being elected. Try again later. at org.opendaylight.controller.cluster.datastore.ShardManager.createNoShardLeaderException(ShardManager.java:392)[190:org.opendaylight.controller.sal-distributed-datastore:1.2.0.Lithium] at org.opendaylight.controller.cluster.datastore.ShardManager.onShardNotInitializedTimeout(ShardManager.java:230)[190:org.opendaylight.controller.sal-distributed-datastore:1.2.0.Lithium] at org.opendaylight.controller.cluster.datastore.ShardManager.handleCommand(ShardManager.java:182)[190:org.opendaylight.controller.sal-distributed-datastore:1.2.0.Lithium] at org.opendaylight.controller.cluster.common.actor.AbstractUntypedPersistentActor.onReceiveCommand(AbstractUntypedPersistentActor.java:36)[182:org.opendaylight.controller.sal-clustering-commons:1.2.0.Lithium] at akka.persistence.UntypedPersistentActor.onReceive(Eventsourced.scala:430)[180:com.typesafe.akka.persistence.experimental:2.3.10] at org.opendaylight.controller.cluster.common.actor.MeteringBehavior.apply(MeteringBehavior.java:97)[182:org.opendaylight.controller.sal-clustering-commons:1.2.0.Lithium] at akka.actor.ActorCell$$anonfunbecome1.applyOrElse(ActorCell.scala:534)[175:com.typesafe.akka.actor:2.3.10] at akka.persistence.RecoveryStateclass.process(Recovery.scala:30)[180:com.typesafe.akka.persistence.experimental:2.3.10] at akka.persistence.ProcessorImpl$$anon$2.process(Processor.scala:103)[180:com.typesafe.akka.persistence.experimental:2.3.10] at akka.persistence.ProcessorImpl$$anon2.aroundReceive(Processor.scala:114)[180:com.typesafe.akka.persistence.experimental:2.3.10] at akka.persistence.Recoveryclass.aroundReceive(Recovery.scala:265)[180:com.typesafe.akka.persistence.experimental:2.3.10] at akka.persistence.UntypedPersistentActor.akkapersistenceEventsourced$$super$aroundReceive(Eventsourced.scala:428)[180:com.typesafe.akka.persistence.experimental:2.3.10] at akka.persistence.Eventsourcedanon\$2.doAroundReceive(Eventsourced.scala:82)[180:com.typesafe.akka.persistence.experimental ...