Start Play with Akka Cluster configuration

Play Framework
1

I add the following akka configuration into my appplication.conf file, to start our Play Website as the first seed node as the akka cluster:

akka {
  actor {
    warn-about-java-serializer-usage = false
    provider = "akka.cluster.ClusterActorRefProvider"
  }

  remote {
    enabled-transports = ["akka.remote.netty.tcp"]
    netty.tcp {
      hostname = "10.91.192.216"
      port = 2551
    }
  }

  cluster {
    seed-nodes = ["akka.tcp://application@10.91.192.216:2551"]
    auto-down-unreachable-after = 10s
  }
}

Then from the log I can see it successfully started as the first node of akka cluster:

[^[[37minfo^[[0m] a.c.Cluster(akka://application) - Cluster Node [akka.tcp://application@10.91.192.216:2551] - Starting up, Akka version [2.5.31] …
[^[[37minfo^[[0m] a.c.Cluster(akka://application) - Cluster Node [akka.tcp://application@10.91.192.216:2551] - Registered cluster JMX MBean [akka:type=Cluster]
[^[[37minfo^[[0m] a.c.Cluster(akka://application) - Cluster Node [akka.tcp://application@10.91.192.216:2551] - Started up successfully
[^[[33mwarn^[[0m] a.c.AutoDown - Don’t use auto-down feature of Akka Cluster in production. See ‘Auto-downing (DO NOT USE)’ section of Akka Cluster documentation.
[^[[37minfo^[[0m] a.c.Cluster(akka://application) - Cluster Node [akka.tcp://application@10.91.192.216:2551] - Node [akka.tcp://application@10.91.192.216:2551] is JOINING itself (with roles [dc-default]) and forming new cluster

But then I found from log, Play is starting another Remote Actor System named Default:

[INFO] [08/02/2020 02:59:26.583] [main] [akka.remote.Remoting] Starting remoting
[INFO] [08/02/2020 02:59:26.660] [main] [akka.remote.Remoting] Remoting started; listening on addresses :[akka.tcp://default@10.91.192.216:2551]
[INFO] [08/02/2020 02:59:26.666] [main] [akka.remote.Remoting] Remoting now listens on addresses: [akka.tcp://default@10.91.192.216:2551]
[INFO] [08/02/2020 02:59:26.673] [main] [akka.cluster.Cluster(akka://default)] Cluster Node [akka.tcp://default@10.91.192.216:2551] - Starting up, Akka version [2.5.31] …
[WARN] [08/02/2020 02:59:26.702] [main] [akka.cluster.Cluster(akka://default)] Could not register Cluster JMX MBean with name=akka:type=Cluster as it is already registered. If you are running multiple clusters in the same JVM, set ‘akka.cluster.jmx.multi-mbeans-in-same-jvm = on’ in config
[INFO] [08/02/2020 02:59:26.702] [main] [akka.cluster.Cluster(akka://default)] Cluster Node [akka.tcp://default@10.91.192.216:2551] - Started up successfully
[WARN] [08/02/2020 02:59:26.736] [default-akka.actor.default-dispatcher-3] [akka.tcp://default@10.91.192.216:2551/system/cluster/core/daemon/downingProvider] Don’t use auto-down feature of Akka Cluster in production. See ‘Auto-downing (DO NOT USE)’ section of Akka Cluster documentation.

also another one named SimpleStream, and then throw me the following error:

[ERROR] [08/02/2020 02:59:28.840] [SimpleStream-akka.remote.default-remote-dispatcher-8] [akka://SimpleStream/system/endpointManager/reliableEndpointWriter-akka.tcp%3A%2F%2Fdefault%4010.91.192.216%3A2551-2/endpointWriter] dropping message [class akka.actor.ActorSelectionMessage] for non-local recipient [Actor[akka.tcp://application@10.91.192.216:2551/]] arriving at [akka.tcp://application@10.91.192.216:2551] inbound addresses are [akka.tcp://SimpleStream@10.91.192.216:2551]
[ERROR] [08/02/2020 02:59:28.840] [SimpleStream-akka.remote.default-remote-dispatcher-9] [akka://SimpleStream/system/endpointManager/reliableEndpointWriter-akka.tcp%3A%2F%2FSimpleStream%4010.91.192.216%3A2551-1/endpointWriter] dropping message [class akka.actor.ActorSelectionMessage] for non-local recipient [Actor[akka.tcp://application@10.91.192.216:2551/]] arriving at [akka.tcp://application@10.91.192.216:2551] inbound addresses are [akka.tcp://SimpleStream@10.91.192.216:2551]

Why so many ActorSystem, and which is the correct way to setup the Play Website as the first node of Actor Cluster System.