[SOLVED] JGroups unstable grouping

JGroups unstable grouping

I am using jgroups reliable multicast to communicate. I have a structure as follows.

A cluster named clusterA contains three nodes.
A node has multiple applications that want to join clusterA multicast.

When I start the applications, first joiner app in each node can join the cluster without problem and can communicate each other. Remaining nodes are unstable that their behaviour changes for each startup. Sometimes they can join the cluster, sometimes not. I could not find any pattern.

A log that I can share is the one saying sth like "... is not a member, discarding message". So, it is seen that it cannot join the cluster. The protocol stack I applied

PING

MERGE2

FD_SOCK

FD_ALL with values "timeout"=12000, "interval"=3000

VERIFY_SUSPECT

BARRIER

NAKACK

UNICAST2

STABLE 

GMS 

UFC 

MFC

FRAG2

How can I handle this problem? (Version 3.6.1.Final)

Solution

I upgraded to jgroups version 4.* and updated protocols with newer versions with one new protocol as follows.

PING

MERGE3

FD_SOCK

FD_ALL with values "timeout"=15000, "interval"=3000

VERIFY_SUSPECT

BARRIER

NAKACK2

UNICAST3

STABLE 

GMS with value "max_join_attempts"=0

UFC 

MFC

FRAG2

STATE_TRANSFER

Not sure which solved problem but "max_join_attempts"=0 part may be the core point as nodes do not give up trying to join the cluster this way.