每20分钟节点会掉线一次。

    org.elasticsearch.discovery.zen.MasterFaultDetection

    

    int retryCount = ++MasterFaultDetection.this.retryCount;

    logger.trace(

        (Supplier<?>) () -> new ParameterizedMessage(

            "[master] failed to ping [{}], retry [{}] out of [{}]",

            masterNode,

            retryCount,

            pingRetryCount),

        exp);

    if (retryCount >= pingRetryCount) {

        logger.debug("[master] failed to ping [{}], tried [{}] times, each with maximum [{}] timeout",

            masterNode, pingRetryCount, pingRetryTimeout);

        // not good, failure

        notifyMasterFailure(masterToPing, null, "failed to ping, tried [" + pingRetryCount

            + "] times, each with  maximum [" + pingRetryTimeout + "] timeout");

    } else {

        // resend the request, not reschedule, rely on send timeout

        transportService.sendRequest(masterToPing, MASTER_PING_ACTION_NAME, request, options, this);

    }

    logger.trace(

    (Supplier<?>) () -> new ParameterizedMessage(

        "[master] failed to ping [{}], retry [{}] out of [{}]",

        masterNode,

        retryCount,

        pingRetryCount),

    exp);

{

  "transient": {

    "logger.org.elasticsearch.discovery": "trace"

  }

}

[internal:discovery/zen/fd/master_ping] Caused by: java.lang.IllegalStateException