在生产模式下为 Lagom 应用程序设置 Akka 集群

Question

我正在尝试在 Akka 集群中以生产模式运行 Lagom 服务，该集群是通过 Akka Cluster Bootstrap 配置的，如 https://www.lagomframework.com/documentation/1.5.x/scala/Cluster.html 中所述。 （我可以通过手动指定种子节点来运行该应用程序）。但是，我无法启动该服务。我有以下设置：

application.conf (only the cluster related configs)
akka.management.cluster.bootstrap {
  # example using kubernetes-api
  contact-point-discovery {
    discovery-method = akka.discovery
#    discovery-method = config
    service-name = "lagom-scala"
    required-contact-point-nr = 0
  }
}

一个应用程序加载器，在生产模式下加载AkkaDiscoveryComponents，如下所述（https://www.lagomframework.com/documentation/1.5.x/scala/AkkaDiscoveryIntegration.html）：

class LagomscalaLoader extends LagomApplicationLoader {

  override def load(context: LagomApplicationContext): LagomApplication =
    new LagomscalaApplication(context) with AkkaDiscoveryComponents

  override def loadDevMode(context: LagomApplicationContext): LagomApplication =
    new LagomscalaApplication(context) with LagomDevModeComponents

  override def describeService = Some(readDescriptor[LagomscalaService])
}

当required-contact-point-nr 设置为0 时，我得到以下日志：

2019-10-28T23:48:54.867Z [info] akka.management.cluster.bootstrap.internal.BootstrapCoordinator [sourceThread=application-akka.actor.default-dispatcher-26, akkaTimestamp=23:48:54.867UTC, akkaSource=akka.tcp://application@192.168.0.34:2552/system/bootstrapCoordinator, sourceActorSystem=application] - Looking up [Lookup(lagom-scala,None,Some(tcp))]
2019-10-28T23:48:54.886Z [info] akka.management.cluster.bootstrap.internal.BootstrapCoordinator [sourceThread=application-akka.actor.default-dispatcher-22, akkaTimestamp=23:48:54.886UTC, akkaSource=akka.tcp://application@192.168.0.34:2552/system/bootstrapCoordinator, sourceActorSystem=application] - Located service members based on: [Lookup(lagom-scala,None,Some(tcp))]: [], filtered to []
2019-10-28T23:48:55.957Z [info] akka.management.cluster.bootstrap.LowestAddressJoinDecider [sourceThread=application-akka.actor.default-dispatcher-16, akkaTimestamp=23:48:55.957UTC, akkaSource=LowestAddressJoinDecider(akka://application), sourceActorSystem=application] - Exceeded stable margins without locating seed-nodes, however this node 192.168.0.34:8558 is NOT the lowest address out of the discovered endpoints in this deployment, thus NOT joining self. Expecting node [] (out of []) to perform the self-join and initiate the cluster.

当我将required-contact-point-nr 设置为2（默认）时，我得到以下日志：

2019-10-29T00:15:57.846Z [info] akka.management.cluster.bootstrap.internal.BootstrapCoordinator [sourceThread=application-akka.actor.default-dispatcher-23, akkaTimestamp=00:15:57.846UTC, akkaSource=akka.tcp://application@192.168.0.34:2552/system/bootstrapCoordinator, sourceActorSystem=application] - Looking up [Lookup(lagom-scala,None,Some(tcp))]
2019-10-29T00:15:57.865Z [info] akka.management.cluster.bootstrap.internal.BootstrapCoordinator [sourceThread=application-akka.actor.default-dispatcher-4, akkaTimestamp=00:15:57.865UTC, akkaSource=akka.tcp://application@192.168.0.34:2552/system/bootstrapCoordinator, sourceActorSystem=application] - Located service members based on: [Lookup(lagom-scala,None,Some(tcp))]: [], filtered to []
2019-10-29T00:15:58.299Z [info] akka.management.cluster.bootstrap.LowestAddressJoinDecider [sourceThread=application-akka.actor.default-dispatcher-3, akkaTimestamp=00:15:58.299UTC, akkaSource=LowestAddressJoinDecider(akka://application), sourceActorSystem=application] - Discovered [0] contact points, confirmed [0], which is less than the required [2], retrying
2019-10-29T00:15:58.599Z [warn] akka.cluster.sharding.ShardRegion [sourceThread=application-akka.actor.default-dispatcher-4, akkaTimestamp=00:15:58.597UTC, akkaSource=akka.tcp://application@192.168.0.34:2552/system/sharding/kafkaProducer-greetings, sourceActorSystem=application] - kafkaProducer-greetings: No coordinator found to register. Probably, no seed-nodes configured and manual cluster join not performed? Total [1] buffered messages.

我使用Akka 2.5.25 和默认配置，除了我上面指定的配置。例如。运行服务后，我看到以下可能相关的日志：

2019-10-29T00:15:44.987Z [info] akka.remote.Remoting [sourceThread=main, akkaTimestamp=00:15:44.987UTC, akkaSource=akka.remote.Remoting, sourceActorSystem=application] - Remoting now listens on addresses: [akka.tcp://application@192.168.0.34:2552]
2019-10-29T00:15:45.276Z [info] akka.cluster.Cluster(akka://application) [sourceThread=application-akka.actor.default-dispatcher-2, akkaSource=akka.cluster.Cluster(akka://application), sourceActorSystem=application, akkaTimestamp=00:15:45.275UTC] - Cluster Node [akka.tcp://application@192.168.0.34:2552] - No seed-nodes configured, manual cluster join required, see https://doc.akka.io/docs/akka/current/cluster-usage.html#joining-to-seed-nodes
2019-10-29T00:15:46.411Z [info] akka.management.cluster.bootstrap.ClusterBootstrap [sourceThread=main, akkaTimestamp=00:15:46.411UTC, akkaSource=ClusterBootstrap(akka://application), sourceActorSystem=application] - Using self contact point address: http://192.168.0.34:8558
2019-10-29T00:15:48.164Z [info] akka.management.scaladsl.AkkaManagement [sourceThread=application-akka.actor.default-dispatcher-24, akkaSource=AkkaManagement(akka://application), sourceActorSystem=application, akkaTimestamp=00:15:48.163UTC] - Bound Akka Management (HTTP) endpoint to: 192.168.0.34:8558
2019-10-29T00:15:48.286Z [info] akka.management.cluster.bootstrap.internal.BootstrapCoordinator [sourceThread=application-akka.actor.default-dispatcher-24, akkaSource=akka.tcp://application@192.168.0.34:2552/system/bootstrapCoordinator, sourceActorSystem=application, akkaTimestamp=00:15:48.285UTC] - Locating service members. Using discovery [akka.discovery.aggregate.AggregateServiceDiscovery], join decider [akka.management.cluster.bootstrap.LowestAddressJoinDecider]
2019-10-29T00:15:48.772Z [info] play.core.server.AkkaHttpServer [] - Listening for HTTP on /0:0:0:0:0:0:0:0:9000

所以，我认为端口之间存在不匹配，但我不知道如何修复它。感谢您的帮助。

Answer 1

问题似乎是本地设置中缺少 DNS 服务器，并且 Lagom 本身不提供 DNS 服务器 正如@tim-moore 在Lightbend forum 所述。