Actually this is not the server side of ESB that I'm talking about. It
is the client side of the ESB.

Anyway if we can test a scenario like this it will be great.

>From code here is what should happen.

We have a connection pool with host name and ip address. So even
though the DNS server is configured to point to a new IP address for a
host name, the connection pool doesn't change. For these connections
to become un-usable the back end server which hosted the services
should be shut down. Until that ESB can still send messages to the old
server because it is taking connections from a connection pool.

When ESB creates new connections after the DNS change, it will do it correctly.

Thanks,
Supun..

On Sat, Dec 12, 2009 at 12:15 PM, Senaka Fernando <[email protected]> wrote:
> Hi Supun,
>
> If you have configured the server to use the host name instead of the ip
> address, it should work without any issues. If you did use the ip address as
> the host name or didn't specify it, the change in ip address could cause
> some aspects not to work, such as calculated EPRs in EventBrokers.
>
> Thanks,
> Senaka.
>
> On Sat, Dec 12, 2009 at 9:35 AM, Afkham Azeez <[email protected]> wrote:
>>
>> Yeah, not only for ESB, but for any generic client-server system this
>> should not cause any problems as long as the first machine is kept online
>> until all requests it received have been served. If that machine is taken
>> offline immediately, the request which were in flight and which were being
>> processed will fail. So there should be a graceful mechanism to do this,
>> like our graceful shutdown procedure. Subsequent requests should be
>> successfully forwarded to the new machine though.
>> Azeez
>>
>> On Sat, Dec 12, 2009 at 5:23 AM, Supun Kamburugamuwa <[email protected]>
>> wrote:
>>>
>>> Hi,
>>>
>>> Suppose we have several back end services and ESB refer to them using
>>> a URL. These URLs are DNS resolvable URLs not IP address. Suppose we
>>> substitute a new physical machine with a different IP and configure
>>> the DNS server to point to the new IP for the same old URL. The
>>> question is what will happen?
>>>
>>> From the code it seems ESB will work correctly. I thought of bringing
>>> this question up to make sure that it will work.
>>>
>>> Thanks,
>>> Supun..
>>>
>>> _______________________________________________
>>> Carbon-dev mailing list
>>> [email protected]
>>> https://mail.wso2.org/cgi-bin/mailman/listinfo/carbon-dev
>>
>>
>>
>> --
>> --
>> Afkham Azeez
>> [email protected]
>> WSO2 Inc. http://wso2.com
>> Blog: http://afkham.org
>>
>> _______________________________________________
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>> [email protected]
>> https://mail.wso2.org/cgi-bin/mailman/listinfo/carbon-dev
>>
>
>
>
> --
> Senaka Fernando
> Software Engineer
> WSO2 Inc.
> E-mail: [email protected];  Mobile: +94 77 322 1818
>
> http://www.wso2.com/ - "The Open Source SOA Company"
>
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>

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