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

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

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

akka {

  cluster {
    # Initial contact points of the cluster.
    # The nodes to join at startup if auto-join = on.
    # Comma separated full URIs defined by a string on the form of
    # "akka://system@hostname:port"
    # Leave as empty if the node should be a singleton cluster.
    seed-nodes = []

    # how long to wait for one of the seed nodes to reply to initial join request
    seed-node-timeout = 5s

    # Automatic join the seed-nodes at startup.
    # If seed-nodes is empty it will join itself and become a single node cluster.
    auto-join = on

    # Should the 'leader' in the cluster be allowed to automatically mark
    # unreachable nodes as DOWN?
    # Using auto-down implies that two separate clusters will automatically be
    # formed in case of network partition.
    auto-down = off

    # Enable or disable JMX MBeans for management of the cluster
    jmx.enabled = on

    # how long should the node wait before starting the periodic tasks
    # maintenance tasks?
    periodic-tasks-initial-delay = 1s

    # how often should the node send out gossip information?
    gossip-interval = 1s

    # how often should the leader perform maintenance tasks?
    leader-actions-interval = 1s

    # how often should the node move nodes, marked as unreachable by the failure
    # detector, out of the membership ring?
    unreachable-nodes-reaper-interval = 1s

    # How often the current internal stats should be published.
    # A value of 0 s can be used to always publish the stats, when it happens.
    publish-stats-interval = 10s

    # A joining node stops sending heartbeats to the node to join if it hasn't
    # become member of the cluster within this deadline.
    join-timeout = 60s

    # The id of the dispatcher to use for cluster actors. If not specified
    # default dispatcher is used.
    # If specified you need to define the settings of the actual dispatcher.
    use-dispatcher = ""

    # Gossip to random node with newer or older state information, if any with
    # 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

    # Limit number of merge conflicts per second that are handled. If the limit is
    # exceeded the conflicting gossip messages are dropped and will reappear later.
    max-gossip-merge-rate = 5.0

    failure-detector {

      # FQCN of the failure detector implementation.
      # It must implement akka.cluster.FailureDetector and
      # have constructor with akka.actor.ActorSystem and
      # akka.cluster.ClusterSettings parameters
      implementation-class = "akka.cluster.AccrualFailureDetector"

      # how often should the node send out heartbeats?
      heartbeat-interval = 1s

      # Number of member nodes that each member will send heartbeat messages to,
      # i.e. each node will be monitored by this number of other nodes.
      monitored-by-nr-of-members = 5

      # defines the failure detector threshold
      #     A low threshold is prone to generate many wrong suspicions but ensures
      #     a quick detection in the event of a real crash. Conversely, a high
      #     threshold generates fewer mistakes but needs more time to detect
      #     actual crashes
      threshold = 8.0

      # Minimum standard deviation to use for the normal distribution in
      # AccrualFailureDetector. Too low standard deviation might result in
      # too much sensitivity for sudden, but normal, deviations in heartbeat
      # inter arrival times.
      min-std-deviation = 100 ms

      # Number of potentially lost/delayed heartbeats that will be
      # accepted before considering it to be an anomaly.
      # It is a factor of heartbeat-interval.
      # This margin is important to be able to survive sudden, occasional,
      # pauses in heartbeat arrivals, due to for example garbage collect or
      # network drop.
      acceptable-heartbeat-pause = 3s

      max-sample-size = 1000
    }

    metrics {
      # Enable or disable metrics collector for load-balancing nodes.
      enabled = on

      # FQCN of the metrics collector implementation.
      # It must implement akka.cluster.cluster.MetricsCollector and
      # have constructor with akka.actor.ActorSystem parameter.
      # The default SigarMetricsCollector uses JMX and Hyperic SIGAR, if SIGAR
      # is on the classpath, otherwise only JMX.
      collector-class = "akka.cluster.SigarMetricsCollector"

      # How often metrics are sampled on a node.
      # Shorter interval will collect the metrics more often.
      collect-interval = 3s

      # How often a node publishes metrics information.
      gossip-interval = 3s

      # How quickly the exponential weighting of past data is decayed compared to
      # new data. Set lower to increase the bias toward newer values.
      # The relevance of each data sample is halved for every passing half-life duration,
      # i.e. after 4 times the half-life, a data sample’s relevance is reduced to 6% of
      # its original relevance. The initial relevance of a data sample is given by
      # 1 – 0.5 ^ (collect-interval / half-life).
      # See http://en.wikipedia.org/wiki/Moving_average#Exponential_moving_average
      moving-average-half-life = 12s
    }

    # If the tick-duration of the default scheduler is longer than the
    # tick-duration configured here a dedicated scheduler will be used for
    # periodic tasks of the cluster, otherwise the default scheduler is used.
    # See akka.scheduler settings for more details about the HashedWheelTimer.
    scheduler {
      tick-duration = 33ms
      ticks-per-wheel = 512
    }

    # Netty blocks when sending to broken connections, and this circuit breaker
    # is used to reduce connect attempts to broken connections.
    send-circuit-breaker {
      max-failures = 3
      call-timeout = 2 s
      reset-timeout = 30 s
    }
  }

  # Default configuration for routers
  actor.deployment.default {
    # MetricsSelector to use
    # - available: "mix", "heap", "cpu", "load"
    # - or:        Fully qualified class name of the MetricsSelector class.
    #              The class must extend akka.cluster.routing.MetricsSelector
    #              and have a constructor with com.typesafe.config.Config
    #              parameter.
    # - default is "mix"
    metrics-selector = mix
  }
  actor.deployment.default.cluster {
    # enable cluster aware router that deploys to nodes in the cluster
    enabled = off

    # Maximum number of routees that will be deployed on each cluster
    # member node.
    # Note that nr-of-instances defines total number of routees, but
    # number of routees per node will not be exceeded, i.e. if you
    # define nr-of-instances = 50 and max-nr-of-instances-per-node = 2
    # it will deploy 2 routees per new member in the cluster, up to
    # 25 members.
    max-nr-of-instances-per-node = 1

    # Defines if routees are allowed to be located on the same node as
    # the head router actor, or only on remote nodes.
    # Useful for master-worker scenario where all routees are remote.
    allow-local-routees = on

    # Actor path of the routees to lookup with actorFor on the member
    # nodes in the cluster. E.g. "/user/myservice". If this isn't defined
    # the routees will be deployed instead of looked up.
    # max-nr-of-instances-per-node should not be configured (default value is 1)
    # when routees-path is defined.
    routees-path = ""

  }

}