[jira] [Created] (ZOOKEEPER-2715) Sessions Expire due to Network partitioning in Zookeeper

["Tharindu Kumara (JIRA)" <ji...@apache.org>]

Tharindu Kumara created ZOOKEEPER-2715:
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             Summary: Sessions Expire due to Network partitioning in Zookeeper 
                 Key: ZOOKEEPER-2715
                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2715
             Project: ZooKeeper
          Issue Type: Bug
          Components: c client
    Affects Versions: 3.4.9
            Reporter: Tharindu Kumara


Recently, carried out a test to to find the behavior of clients when a 
client is partitioned from the ensemble. 

Here used a ensemble of 3 zookeeper servers called A, B and C. And quorum was set up like below. 

A - Follower 
B - Leader 
C - Follower​ 

A  <---> B <---> C 
   \__________/ 

And 3 clients are connected to ensemble like below. 

C1 is connected A 
C2 is connected B 
C3 is connected C. 

To remove the network link between B and C iptables utility is used. 

command used: 
iptables -I INPUT -s Server_B_IP -j DROP 
iptables -I INPUT -s Server_C_IP -j DROP 

After removing the link connections looks like below. 

A  <----> B         C 
   \___________/ 

Simply there is no way to send any packets from from B to C and vice versa. But the connection exists between between B and C.

Here What I noticed is that the client connected to Zookeeper Server "C", could not connect to the ensemble resulting a session expiration timeout. 

For this experiment I used tickTime of 3000ms and client session expiration timeout of 45000ms. And tested with different combinations also. 



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