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  1. JGroups
  2. JGRP-1977

More redundant initial join logic to avoid becoming a fake coordinator

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Details

    • Enhancement
    • Status: Resolved (View Workflow)
    • Major
    • Resolution: Rejected
    • None
    • 3.6.7
    • None

    Description

      If the very initial JGroups discovery packet is lost, it is never recovered by the current GMS join logic. The node will be a standalone coordinator then merges after several minutes.

      This can happen if a new node reside in another network segment and a switch between the segments requires some time to establish a new multicast route. Currently, there is no enough time between IGMP join (by MulticastSocket#joinGroup()) and the JGroups discovery packet and the later is lost in such a network environment. Because the number of nodes can be very large, configuring a static route in the switch is not reasonable.

      Specifically, in method org.jgroups.protocols.pbcast.ClientGmsImpl#joinInternal(), part of gms.getDownProtocol().down(Event.FIND_INITIAL_MBRS_EVT) is outside of the retry loop of GMS.max_join_attempts and GMS.join_timeout.

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            rhn-engineering-bban Bela Ban
            rhn-support-onagano Osamu Nagano
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              Created:
              Updated:
              Resolved: