Hi ,

Double assignment , when participant is not able to establish connection with 
zookeeper quorum

Following is the  set up.

Version(s) :
                                Helix: 0.7.1
                                Zookeeper:3.3.4

- State Model: OnlineOffline
- Controller (leader elected from one of the cluster nodes)
- Single resources with partitions.
- Full auto rebalancer

-Zookeeper quorum (3 nodes)

When one participant loses the zookeeper connection (It's not able to connect 
to any of the zookeepers , a typical occurrence we faced was switch failure 
from that rack)

  ---- >  The partition (P1) for which this participant (say Node N1) is online 
is still maintained

Meanwhile since it loses the ephemeral  node in zookeeper , the rebalancer gets 
triggered and it reallocates the partition (P1) to another participant node 
(say Node N2) to become online  @ time T1

                ---- >  After this both N1 and N2 are acting as online for the 
same Partition (P1)

But as soon as participant in (say Node N1) is able to re-establish the 
zookeeper connection  @ time T2
                ---- >  Reset gets called on the partition in participant (say 
Node N1)

Double assignment:
The question here is this an expected behavior that both nodes N1 and N2 could 
be online for the same Partition (P1) between time (T1-T2) ? Any responses on 
the same would be appreciated.

Thanks & Regards,
Subramanian.

3400 Hillview Ave, Building 4
Palo Alto, CA 94304
www.integral.com<http://www.integral.com/>
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