tomcat-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Mohit Anchlia <mohitanch...@gmail.com>
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 <rainer.jung@kippdata.de> wrote:
> On 06.06.2010 03:52, Mohit Anchlia wrote:
>>
>> On Sat, Jun 5, 2010 at 2:02 AM, Rainer Jung<rainer.jung@kippdata.de>
>>  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 worker.properties 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
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
> For additional commands, e-mail: users-help@tomcat.apache.org
>
>

---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@tomcat.apache.org
For additional commands, e-mail: users-help@tomcat.apache.org


Mime
View raw message