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Date: Mon, 17 May 2010 17:09:20 -0400
From: Donald Woods <dwoods@apache.org>
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To: users@openjpa.apache.org
Subject: Re: configure RemoteCommitProvider for Amazon EC2
References: <BF8EF86E-0699-4750-9E58-2D4211C13593@oliverkrohne.de>
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On 5/17/10 5:20 AM, Oliver Krohne wrote:
> Hi,
> 
> we are going to deploy our app to Amazon EC2.
> One issue is that the ip-adresses of an ec instance can change and new ec instances
> can be started which makes the RemoteCommitProvider using TCP unuseable as all
> TCP adresses where messages are sent to must be configured at the point the 
> instance is starting. New instances can't be added without reconfiguring the running ec instances.

What about the Amazon Simple Queue Service (SQS)?

> 
> Using JMS as transport would work but i don't want a another machine running and hence a new point of failure.
> But I would be thankful for any experience using JMS (openjms or activemq?).

I've only used ActiveMQ as a JMS provider in Apache Geronimo, but it
does have robust discovery and fail-over mechanisms.
http://activemq.apache.org/configuring-version-5-transports.html
http://activemq.apache.org/networks-of-brokers.html
http://activemq.apache.org/failover-transport-reference.html

> 
> So am thinking of using jgroups were new instances can join a channel, but I did not found someone 
> who has implemented it, maybe in this mailinglist?
> 
> The other solution would be using ehcache with jgroups replication and 
> just replicate "removes and updates". Does anyone have experience with this setup?

To use ehcache, you'd need to create a EhcaheRemoteCommitProvider that
can instantiate a CacheManager and Cache based on a XML configuration
file.  I've opened OPENJPA-1669 and started looking at creating one for
trunk :-)

-Donald

> 
> 
> Thanks,
> Oliver