java - Akka 中的集群

Question

我正在尝试了解 Akka Clustering 以使用节点进行并行计算。因此，我编写了一个阶乘程序，并希望在 3 个节点(包括主节点)的集群上运行该程序。

我正在使用配置文件来提供种子节点和集群提供程序。并在我的代码中读取文件。

cluster {
  akka {
    actor {
      provider = "cluster"
    }
    remote {
      log-remote-lifecycle-events = off
      netty.tcp {
        hostname = "127.0.0.1"
        port = 0
      }
    }

    cluster {
      seed-nodes = [
        "akka.tcp://ClusterSystem@127.0.0.1:9876",
        "akka.tcp://ClusterSystem@127.0.0.1:6789"]

      # auto downing is NOT safe for production deployments.
      # you may want to use it during development, read more about it in the docs.
      #
      # auto-down-unreachable-after = 10s
    }
  }
}

以下是java代码:

package test

import java.io.File

import akka.actor.{Actor,ActorSystem, Props}
import akka.stream.ActorMaterializer
import com.typesafe.config.ConfigFactory

import scala.concurrent.ExecutionContextExecutor


class Factorial extends Actor {
  override def receive = {
    case (n: Int) => fact(n)
  }

  def fact(n:Int): Int ={
    if (n<=1){
      return 1
    }
    else {
      return n * fact(n - 1)
    }
  }
}

object ClusterActor {
  def main(args: Array[String]): Unit = {

    val configFile = "E:/Scala/StatsRuleEngine/Resources/local_configuration.conf"
    val config = ConfigFactory.parseFile(new File(configFile))

    implicit val system:ActorSystem = ActorSystem("ClusterSystem" ,config.getConfig("cluster"))
    implicit val materializer:ActorMaterializer = ActorMaterializer()
    implicit val executionContext: ExecutionContextExecutor = system.dispatcher

    val FacActor = system.actorOf(Props[Factorial],"Factorial")

    FacActor ! (5)
  }
}

运行程序时，出现以下错误

Remote connection to [null] failed with java.net.ConnectException: Connection refused: no further information: /127.0.0.1:6789 [WARN] [01/21/2019 16:31:15.979] [New I/O boss #3] [NettyTransport(akka://ClusterSystem)] Remote connection to [null] failed with java.net.ConnectException: Connection refused: no further information: /127.0.0.1:9876

我尝试搜索，但不知道为什么会出现此错误。

Answer 1

启动节点时，您需要指定将在配置中打开的确切端口

  netty.tcp {
    hostname = "127.0.0.1"
    port = 0 // THE EXACT PORT
  }

因此，如果您的种子节点为 9876 和 6789。两个节点必须指定

  netty.tcp {
    hostname = "127.0.0.1"
    port = 9876
  }

和

  netty.tcp {
    hostname = "127.0.0.1"
    port = 6789
  }

请注意，种子节点列表中第一个列出的节点必须首先启动。