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From Mohit Anchlia <>
Subject Re: fail_on_status question
Date Mon, 07 Jun 2010 01:24:06 GMT
On Sun, Jun 6, 2010 at 6:40 AM, Rainer Jung <> wrote:
> On 06.06.2010 03:52, Mohit Anchlia wrote:
>> On Sat, Jun 5, 2010 at 2:02 AM, Rainer Jung<>
>>  wrote:
>>> On 04.06.2010 01:30, Mohit Anchlia wrote:
>>>> In our present environment we have a WS and APP server. When request
>>>> comes in, WS sends it to APP server using mod_jk and then APP server
>>>> inserts it into JMS queue. So essentially APP server is also dependent
>>>> on JMS server which runs on the same box.
>>>> My question is can I use fail_on_status in to take
>>>> one of the APP servers out of service from mod_jk(WS) by returning
>>>> some Http error code as a response to a request when JMS server is
>>>> down and a request comes in? Since cping and cpong will still return
>>>> success would this mechanism of fail_on_status work?
>>> fail_on_status will trigger nevertheless. Otherwise it would be useless.
>> I didn't get this piece that fail_on_status will trigger nevertheless?
>> My understanding is that cping and cpong decide if to keep a worker in
>> error state or not. But http response code will be returned only when
>> http request comes in. To cping and cpong server is still up. So even
>> if app server return status same as configured for fail_on_status
>> cping and cpong will still not bring the worker in error state.
> cping and cpong themselves don't bring the worker in error state. There are
> several mechanism involved to detect feilure and each of those mechanisms
> can bring worker into error state by itself. Once the worker is in error
> state, it will not be used for 60 seconds and then retried with the next
> request eligible for it. If that requests triggers some error condition
> again, the worker will stay in error state, otherwise it will be back to
> normal.
> So if cping/cpong succeed, and later during processing of the same request
> an error occurs, like e.g. triggered by fail_on_status or reply_timeout or
> whatever else is configured, the worker will be put into error state.
> If you still doubt it: try it! Writing a simple servlet or JSP returning
> some error status is easy and you can see what's happening.

Thanks. I'll try it
> Regards,
> Rainer
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