Moved GossipDifferentViewProbability to config, see #2253

akka-cluster/src/main/resources/reference.conf

@@ -52,6 +52,11 @@ akka {
     # of the cluster within this deadline.
     join-timeout = 60s
 
+    # Gossip to random node with newer or older state information, if any with some
+    # this probability. Otherwise Gossip to any random live node.
+    # Probability value is between 0.0 and 1.0. 0.0 means never, 1.0 means always.
+    gossip-different-view-probability = 0.8
+
     failure-detector {
 
       # defines the failure detector threshold

akka-cluster/src/main/scala/akka/cluster/Cluster.scala

@@ -1066,8 +1066,6 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
     }
   }
 
-  private def gossipToDifferentViewProbability: Double = 0.8
-
   /**
    * INTERNAL API.
    *
@@ -1099,7 +1097,7 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
         } yield address
       }
       val gossipedToAlive =
-        if (nodesWithdifferentView.nonEmpty && ThreadLocalRandom.current.nextDouble() < gossipToDifferentViewProbability)
+        if (nodesWithdifferentView.nonEmpty && ThreadLocalRandom.current.nextDouble() < GossipDifferentViewProbability)
           gossipToRandomNodeOf(nodesWithdifferentView.toIndexedSeq)
         else
           gossipToRandomNodeOf(localMemberAddresses)

akka-cluster/src/main/scala/akka/cluster/ClusterSettings.scala

@@ -36,6 +36,7 @@ class ClusterSettings(val config: Config, val systemName: String) {
   final val AutoJoin: Boolean = getBoolean("akka.cluster.auto-join")
   final val AutoDown: Boolean = getBoolean("akka.cluster.auto-down")
   final val JoinTimeout: Duration = Duration(getMilliseconds("akka.cluster.join-timeout"), MILLISECONDS)
+  final val GossipDifferentViewProbability: Double = getDouble("akka.cluster.gossip-different-view-probability")
   final val SchedulerTickDuration: Duration = Duration(getMilliseconds("akka.cluster.scheduler.tick-duration"), MILLISECONDS)
   final val SchedulerTicksPerWheel: Int = getInt("akka.cluster.scheduler.ticks-per-wheel")
 }

akka-cluster/src/test/scala/akka/cluster/ClusterConfigSpec.scala

@@ -32,6 +32,7 @@ class ClusterConfigSpec extends AkkaSpec {
       NrOfGossipDaemons must be(4)
       AutoJoin must be(true)
       AutoDown must be(true)
+      GossipDifferentViewProbability must be(0.8 plusOrMinus 0.0001)
       SchedulerTickDuration must be(33 millis)
       SchedulerTicksPerWheel must be(512)
     }