[infinispan-dev] JGroups 2.8 and Infinispan

[Bela Ban]

I created https://jira.jboss.org/jira/browse/JGRP-989 to dynamically add 
members to TCPPING.initial_hosts, this is done via a bounded list. This 
should help with merges ... actually it does, I tested it.

But this won't work:

    * initial_hosts=A,B
    * Start A: {A}
    * Start B: {A,B}
    * Start C: {A,B,C}
    * Kill A and B: {C}
    * Start D: {D} *not* {C,D} !

The reason is that D won't ping C because it only knows about A and B in 
initial_hosts.

Again, the idea of TCPPING is that this is a static list of servers, in 
a static environment. If you want dynamically changing clusters, use 
either MPING (if multicasting is enabled) or TCPGOSSIP.


Bela Ban wrote:
> In the 2.8 version, you must list *all* servers in the cluster in 
> TCPPING.initial_hosts ! We will not be able to send messages to any 
> server not in this list because we don't have its physical address !
>
> We've been discussing this on the jg-dev list recently, and an idea is 
> to add new servers not in the list to the list dynamically. Question 
> is when to remove them...
>
> While this is beeing discussed, I suggest you use MPING for the time 
> being
>
>
> Manik Surtani wrote:
>> Guys I am seeing problems here again.
>>
>> Vladimir, you mentioned the problems you saw earlier had to do with 
>> nodes not being in the initial TCPPING discovery list.
>>
>> In one of my dist rehash tests, I see this as well, although I don't 
>> think it has to do with the initial discovery list.
>>
>> The test (will be in SVN soon) is 
>> o.i.distribution.RehashTest#testNoDataLoss()
>>
>> The test starts 3 caches, populates state.  So far so good.
>> Adds 3 more caches to the cluster.  Now here, in the process of 
>> adding these, some of the original nodes cannot "see" some new nodes 
>> even though views have been installed, leading to dropped packets.
>> (the next part of the test kills the 3 original nodes, but the test 
>> never gets this far).
>>
>> This is the sort of message we see in the logs.  Wonder if the "no 
>> physical address" bit sheds any light.  (Note that the JGroups 
>> address has been replaced with CACHE1..CACHE6 in the logs for 
>> readability)
>>
>> 2009-06-11 11:28:59,854 WARN  [org.jgroups.protocols.TCP] 
>> (OOB-6,Infinispan-Cluster,CACHE3) no physical address for CACHE5, 
>> dropping message
>>
>> Also, just so you know, this works perfectly well with JGroups 2.7.0.GA.
>>
>> Any thoughts/ideas?
>>
>> Cheers
>> -- 
>> Manik Surtani
>> manik at jboss.org
>> Lead, Infinispan
>> Lead, JBoss Cache
>> http://www.infinispan.org
>> http://www.jbosscache.org
>>
>>
>>
>>
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>

-- 
Bela Ban
Lead JGroups / Clustering Team
JBoss - a division of Red Hat