Module org.elasticsearch.server
Package org.elasticsearch.cluster

Class NodeConnectionsService

java.lang.Object
org.elasticsearch.common.component.AbstractLifecycleComponent
org.elasticsearch.cluster.NodeConnectionsService
All Implemented Interfaces:
Closeable, AutoCloseable, LifecycleComponent, Releasable
public class NodeConnectionsService extends AbstractLifecycleComponent
This component is responsible for maintaining connections from this node to all the nodes listed in the cluster state, and for disconnecting from nodes once they are removed from the cluster state. It periodically checks that all connections are still open and restores them if needed. Note that this component is *not* responsible for removing nodes from the cluster state if they disconnect or are unresponsive: this is the job of the master's fault detection components, particularly FollowersChecker.

The connectToNodes(DiscoveryNodes, Runnable) and disconnectFromNodesExcept(DiscoveryNodes) methods are called on the ClusterApplier thread. This component allows the ClusterApplier to block on forming connections to _new_ nodes, because the rest of the system treats a missing connection with another node in the cluster state as an exceptional condition and we don't want this to happen to new nodes. However we need not block on re-establishing existing connections because if a connection is down then we are already in an exceptional situation and it doesn't matter much if we stay in this situation a little longer.

This component does not block on disconnections at all, because a disconnection might need to wait for an ongoing (background) connection attempt to complete first.

  • Field Details

    • CLUSTER_NODE_RECONNECT_INTERVAL_SETTING

      public static final Setting<TimeValue> CLUSTER_NODE_RECONNECT_INTERVAL_SETTING

  • Constructor Details

  • Method Details

    • connectToNodes

      public void connectToNodes(DiscoveryNodes discoveryNodes, Runnable onCompletion)
      Connect to all the given nodes, but do not disconnect from any extra nodes. Calls the completion handler on completion of all connection attempts to _new_ nodes, without waiting for any attempts to re-establish connections to nodes that were already known.

    • disconnectFromNodesExcept

      public void disconnectFromNodesExcept(DiscoveryNodes discoveryNodes)
      Disconnect from any nodes to which we are currently connected which do not appear in the given nodes. Does not wait for the disconnections to complete, because they might have to wait for ongoing connection attempts first.

    • doStart

      protected void doStart()
      Description copied from class: AbstractLifecycleComponent
      Start this component. Typically that means doing things like launching background processes and registering listeners on other components. Other components have been initialized by this point, but may not yet be started.

      If this method throws an exception then the startup process will fail, but this component will not be stopped before it is closed.

      This method is called while synchronized on AbstractLifecycleComponent.lifecycle. It is only called once in the lifetime of a component, although it may not be called at all if the startup process encountered some kind of fatal error, such as the failure of some other component to initialize or start.

      Specified by:
      doStart in class AbstractLifecycleComponent

    • doStop

      protected void doStop()
      Description copied from class: AbstractLifecycleComponent
      Stop this component. Typically that means doing the reverse of whatever AbstractLifecycleComponent.doStart() does.

      This method is called while synchronized on AbstractLifecycleComponent.lifecycle. It is only called once in the lifetime of a component, after calling AbstractLifecycleComponent.doStart(), although it will not be called at all if this component did not successfully start.

      Specified by:
      doStop in class AbstractLifecycleComponent

    • doClose

      protected void doClose()
      Description copied from class: AbstractLifecycleComponent
      Close this component. Typically that means doing the reverse of whatever happened during initialization, such as releasing resources acquired there.

      This method is called while synchronized on AbstractLifecycleComponent.lifecycle. It is called once in the lifetime of a component. If the component was started then it will be stopped before it is closed, and once it is closed it will not be started or stopped.

      Specified by:
      doClose in class AbstractLifecycleComponent

    • reconnectToNodes

      public void reconnectToNodes(DiscoveryNodes discoveryNodes, Runnable onCompletion)