Ludovic Maitre wrote:
Hi Jeff and all,
I will do the second guinea pig, i would like to run 3 tomcat instances
inside geronimo. The purpose is to be able to upgrade apps on my website
without downtime. I was wondering if i can derivate some GBeans to
implements some "farming" on my cluster (deploy the webapps on each node
as i understand it -- but i just began to transpose the concepts i know
from weblogic to geronimo).
I don't understand yet why multiples IPs are required but sure i will
see the problem when i will implement this setup, (actually this *seems*
to run fine with apache2 as load balancer and my 3 tomcat instances
listenning to differents ports),
Many thanks for having committed the GBeans i will check out them now,
Yep...different ports works peachy too ;-)
Best regards,
Jeff Genender wrote:
Dave Colasurdo wrote:
I'm interested in testing and helping to document geronimo Tomcat
clustering. As a first step, I've setup a Tomcat cluster independent
of Geronimo. Once I get this fully working, I plan to reuse the
configuration info in the geronimo environment.
Thank you for taking the initiative on this. You will be our main
test on this since it has been limited for me due to my time constraints.
I've managed to setup the Apache http server and mod_jk as the load
balancer and do see the requests get sprayed to different tomcat
servers (on two diferent machines). Sticky port is enabled and I see
the node id in the cookie and the rewritten url..
Initially, I tried using memory replication. Cluster membership
between the nodes isn't working. I believe this is due to the fact
that both machines are using DHCP and that their IP addresses aren't
on the same subnet. I can always use two Tomcat installs on the same
machine though was hoping to setup a more realistic scenario using
multiple machines. I guess I need to setup a shared file system or
use a database.
Any advice?
Yep...(relative to geronimo) if you want to run it on the same
machine...you have some hacking to do on the plans. You should be
able to alias your IP address to support multiple IPs. Then in the
Tomcat plan, you need the connectors of each instance to listen on one
of the IP addresses (of course each instance should be listening on a
different IP address). For stand alone tomcat, this would be a
similar process...the connectors need to listen on their own addresses.
IMHO, I would test this on multiple machines before a single machine
with a single instance since you will probably run into other problems
as well with other services in Geronimo. After you get a
multi-machine cluster working, then we can configure it for a single
machine.
Also, The engine GBean needs to use the jvmRoute initparam and you
should make separate names for each instance (i.e. node1, node2, etc).
Assuming this works out.. A few question concerning running
clustering within Geronimo.
For tomcat, I update server.xml to configure AJP Connector, Cluster
config, Engine jvmRoute, etc.. How will we configure silmilar type
information in Geronimo?
It follows the same paradigm as the other Tomcat GBeans. You can set
up a cluster at the Engine, Host, or Context level. The Valves and
Realms are a great example of this. For the host and engine
clustering you will do it in the j2ee-tomcat-plan.xml. For context
you will do it in a geronimo-web.xml or web descriptor plan.
I will write up an example and email it to the lists and then you can
give it a try.
Do the distributable applications need to create deployment plans
that reference the new GBeans?
Depends whether you only want to cluster at a Context level or a host
level.
Any additional steps?
Yep...stay tuned...I'll write something up. Thank you very much for
being the guinea p^H^H^H^H^H^H^H^H test person on this ;-)
Thanks
-Dave-
Jeff Genender wrote:
I have checked in some initial Clustering GBeans for Tomcat. As I
developed this, it appeared that the Tomcat version 5.5.9 did not
match the Tomcat doc. This led me to examine the Tomcat objects and
changelog. It would appear that there were some improvements
between TC v 5.5.9 and 5.5.12, especially with regard to
Clustering. so due to this, I have upgraded our version of Tomcat
to 5.5.12.
I have tested this with some of our applications (i.e. console) and
the unit tests. All looks good to me... so far ;-)
If there are any issues, let me know.
Jeff
