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Posted to users@tomcat.apache.org by Shiby Maria John <Sh...@ibsplc.com> on 2008/01/11 07:11:32 UTC
doubt in clustering with sticky sessions
Hi,
This is a bit of documentation from the Load balancing page of the
Apache site.
sticky_session specifies whether requests with SESSION
ID's should be routed back to the same Tomcat worker. You
can set sticky_session to False when Tomcat is using a
Session Manager which can persist session data across
multiple instances of Tomcat. By default sticky_session
is set to True.
I tired to set the sticky_session value as false, and I was under the
impression that Tomcat has a session manager which can persist session
data across the multiple instances in cluster. But when i set it to
false, the requests are being served by different servers in the
cluster for the same session... That is the session is no longer
sticky. But when this happens sometimes the session replication is
going wrong.
Please make this point clear for me .
Regards,
Shiby
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Re: doubt in clustering with sticky sessions
Posted by Shiby Maria John <Sh...@ibsplc.com>.
Thanks for the info.
So I think if I am using Tomcat for clustering, I need to set
sticky_session as true to ensure that the session is not lost.
Rainer Jung
<rainer.jung@ki
ppdata.de> To
Tomcat Users List
01/11/2008 <us...@tomcat.apache.org>
04:47 PM cc
Subject
Please respond Re: doubt in clustering with
to sticky sessions
"Tomcat Users
List"
<users@tomcat.a
pache.org>
Shiby Maria John wrote:
> Hi,
>
> This is a bit of documentation from the Load balancing page of the
> Apache site.
>
>
> sticky_session specifies whether requests with SESSION
> ID's should be routed back to the same Tomcat worker.
You
> can set sticky_session to False when Tomcat is using a
> Session Manager which can persist session data across
> multiple instances of Tomcat. By default sticky_session
> is set to True.
>
>
>
>
>
> I tired to set the sticky_session value as false, and I was under
the
> impression that Tomcat has a session manager which can persist
session
> data across the multiple instances in cluster. But when i set it to
> false, the requests are being served by different servers in the
> cluster for the same session... That is the session is no longer
> sticky. But when this happens sometimes the session replication is
> going wrong.
>
> Please make this point clear for me .
The mod_jk lb worker attribute sticky_session only influences the
behaviour of the respective mod_jk bao"ancing worker. It doesn't
change
the behaviour of any Tomcat backend.
If you have multiple backends and not session replication is activated
on them, you need to use sticky_session, otherwise most of the time
users will get errors, because the sessions requested don't exist on
the
nodes, which should handle the requests.
If you want to use session replication, e.g. as a means of increasing
the application availability, you need to configure a so called Tomcat
cluster. All you need for this is included with Tomcat, but it is not
active by default. Have a look at the Tomcat cluster docs.
Once you have successfully build up a Tomcat cluster with session
replication, a request could go to any cluster member, because they
all
share the session state. So you are free to set sticky_session to
false.
There are situations though, where you still want sticky_session=true,
although using session replication. It will depend on the application
and the goals of your setup.
Regards,
Rainer
>
> Regards,
> Shiby
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Re: doubt in clustering with sticky sessions
Posted by Rainer Jung <ra...@kippdata.de>.
Shiby Maria John wrote:
> Hi,
>
> This is a bit of documentation from the Load balancing page of the
> Apache site.
>
>
> sticky_session specifies whether requests with SESSION
> ID's should be routed back to the same Tomcat worker. You
> can set sticky_session to False when Tomcat is using a
> Session Manager which can persist session data across
> multiple instances of Tomcat. By default sticky_session
> is set to True.
>
>
>
>
>
> I tired to set the sticky_session value as false, and I was under the
> impression that Tomcat has a session manager which can persist session
> data across the multiple instances in cluster. But when i set it to
> false, the requests are being served by different servers in the
> cluster for the same session... That is the session is no longer
> sticky. But when this happens sometimes the session replication is
> going wrong.
>
> Please make this point clear for me .
The mod_jk lb worker attribute sticky_session only influences the
behaviour of the respective mod_jk bao"ancing worker. It doesn't change
the behaviour of any Tomcat backend.
If you have multiple backends and not session replication is activated
on them, you need to use sticky_session, otherwise most of the time
users will get errors, because the sessions requested don't exist on the
nodes, which should handle the requests.
If you want to use session replication, e.g. as a means of increasing
the application availability, you need to configure a so called Tomcat
cluster. All you need for this is included with Tomcat, but it is not
active by default. Have a look at the Tomcat cluster docs.
Once you have successfully build up a Tomcat cluster with session
replication, a request could go to any cluster member, because they all
share the session state. So you are free to set sticky_session to false.
There are situations though, where you still want sticky_session=true,
although using session replication. It will depend on the application
and the goals of your setup.
Regards,
Rainer
>
> Regards,
> Shiby
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