reference.conf

############################################
# Akka Cluster Tools Reference Config File #
############################################

# This is the reference config file that contains all the default settings.
# Make your edits/overrides in your application.conf.

# //#singleton-config
akka.cluster.singleton {
  # The actor name of the child singleton actor.
  singleton-name = "singleton"

  # Singleton among the nodes tagged with specified role.
  # If the role is not specified it's a singleton among all nodes in the cluster.
  role = ""

  # When a node is becoming oldest it sends hand-over request to previous oldest,
  # that might be leaving the cluster. This is retried with this interval until
  # the previous oldest confirms that the hand over has started or the previous
  # oldest member is removed from the cluster (+ akka.cluster.down-removal-margin).
  hand-over-retry-interval = 1s

  # The number of retries are derived from hand-over-retry-interval and
  # akka.cluster.down-removal-margin (or ClusterSingletonManagerSettings.removalMargin),
  # but it will never be less than this property.
  # After the hand over retries and it's still not able to exchange the hand over messages
  # with the previous oldest it will restart itself by throwing ClusterSingletonManagerIsStuck,
  # to start from a clean state. After that it will still not start the singleton instance
  # until the previous oldest node has been removed from the cluster.
  # On the other side, on the previous oldest node, the same number of retries - 3 are used
  # and after that the singleton instance is stopped.
  # For large clusters it might be necessary to increase this to avoid too early timeouts while
  # gossip dissemination of the Leaving to Exiting phase occurs. For normal leaving scenarios
  # it will not be a quicker hand over by reducing this value, but in extreme failure scenarios
  # the recovery might be faster.
  min-number-of-hand-over-retries = 15

  # Config path of the lease to be taken before creating the singleton actor
  # if the lease is lost then the actor is restarted and it will need to re-acquire the lease
  # the default is no lease
  use-lease = ""

  # The interval between retries for acquiring the lease
  lease-retry-interval = 5s
  
  # Should akka.cluster.app-version be considered when the cluster singleton instance is being moved to another node
  # When set to false, singleton instance will always be created on oldest member
  # When set to true, singleton instance will be created on the oldest node with the highest member app-version number
  consider-app-version = false
}
# //#singleton-config

# //#singleton-proxy-config
akka.cluster.singleton-proxy {
  # The actor name of the singleton actor that is started by the ClusterSingletonManager
  singleton-name = ${akka.cluster.singleton.singleton-name}

  # The role of the cluster nodes where the singleton can be deployed.
  # If the role is not specified then any node will do.
  role = ""

  # Interval at which the proxy will try to resolve the singleton instance.
  singleton-identification-interval = 1s

  # If the location of the singleton is unknown the proxy will buffer this
  # number of messages and deliver them when the singleton is identified.
  # When the buffer is full old messages will be dropped when new messages are
  # sent via the proxy.
  # Use 0 to disable buffering, i.e. messages will be dropped immediately if
  # the location of the singleton is unknown.
  # Maximum allowed buffer size is 10000.
  buffer-size = 1000
}
# //#singleton-proxy-config

# Serializer for cluster ClusterSingleton messages
akka.actor {
  serializers {
    akka-singleton = "Akka.Cluster.Tools.Singleton.Serialization.ClusterSingletonMessageSerializer, Akka.Cluster.Tools"
  }
  serialization-bindings {
    "Akka.Cluster.Tools.Singleton.IClusterSingletonMessage, Akka.Cluster.Tools" = akka-singleton
  }
  serialization-identifiers {
    "Akka.Cluster.Tools.Singleton.Serialization.ClusterSingletonMessageSerializer, Akka.Cluster.Tools" = 14
  }
}