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Date: Thu, 9 Mar 2017 07:15:38 +0000 (UTC)
From: "Tharindu Kumara (JIRA)" <jira@apache.org>
To: dev@zookeeper.apache.org
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Subject: [jira] [Updated] (ZOOKEEPER-2715) Sessions Expire due to Network
 partitioning in Zookeeper
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archived-at: Thu, 09 Mar 2017 07:15:45 -0000


     [ https://issues.apache.org/jira/browse/ZOOKEEPER-2715?page=3Dcom.atla=
ssian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Tharindu Kumara updated ZOOKEEPER-2715:
---------------------------------------
    Description:=20
Recently, carried out a test to to find the behavior of clients when a=20
client is partitioned from the ensemble.=20

Here used a ensemble of 3 zookeeper servers called A, B and C. And quorum w=
as set up like below.=20

A - Follower=20
B - Leader=20
C - Follower=E2=80=8B=20

A  <---> B <---> C=20
 |____________|

And 3 clients are connected to ensemble like below.=20

C1 is connected A=20
C2 is connected B=20
C3 is connected C.=20

To remove the network link between B and C iptables utility is used.=20

command used:=20
iptables -I INPUT -s Server_B_IP -j DROP=20
iptables -I INPUT -s Server_C_IP -j DROP=20

After removing the link connections looks like below.=20

A  <----> B         C=20
 |____________|

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", c=
ould not connect to the ensemble resulting a session expiration timeout.=20

For this experiment I used tickTime of 3000ms and client session expiration=
 timeout of 45000ms. And tested with different combinations also.=20

  was:
Recently, carried out a test to to find the behavior of clients when a=20
client is partitioned from the ensemble.=20

Here used a ensemble of 3 zookeeper servers called A, B and C. And quorum w=
as set up like below.=20

A - Follower=20
B - Leader=20
C - Follower=E2=80=8B=20

A  <---> B <---> C=20
   \__________/=20

And 3 clients are connected to ensemble like below.=20

C1 is connected A=20
C2 is connected B=20
C3 is connected C.=20

To remove the network link between B and C iptables utility is used.=20

command used:=20
iptables -I INPUT -s Server_B_IP -j DROP=20
iptables -I INPUT -s Server_C_IP -j DROP=20

After removing the link connections looks like below.=20

A  <----> B         C=20
   \___________/=20

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", c=
ould not connect to the ensemble resulting a session expiration timeout.=20

For this experiment I used tickTime of 3000ms and client session expiration=
 timeout of 45000ms. And tested with different combinations also.=20


> Sessions Expire due to Network partitioning in Zookeeper=20
> ---------------------------------------------------------
>
>                 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=20
> client is partitioned from the ensemble.=20
> Here used a ensemble of 3 zookeeper servers called A, B and C. And quorum=
 was set up like below.=20
> A - Follower=20
> B - Leader=20
> C - Follower=E2=80=8B=20
> A  <---> B <---> C=20
>  |____________|
> And 3 clients are connected to ensemble like below.=20
> C1 is connected A=20
> C2 is connected B=20
> C3 is connected C.=20
> To remove the network link between B and C iptables utility is used.=20
> command used:=20
> iptables -I INPUT -s Server_B_IP -j DROP=20
> iptables -I INPUT -s Server_C_IP -j DROP=20
> After removing the link connections looks like below.=20
> A  <----> B         C=20
>  |____________|
> Simply there is no way to send any packets from from B to C and vice vers=
a. 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.=
=20
> For this experiment I used tickTime of 3000ms and client session expirati=
on timeout of 45000ms. And tested with different combinations also.=20


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