Hello. This is just a friendly plea to those who have successfully
clustered orion to contact me at Eldan Software. We have already commited
to using orion and currently have a *production* web application running off
an orion server. The client company has now asked us to add two more
servers to serve their web application.
At the time we went with orion we knew we would eventually have to cluster
them. From from reading the how-to doc and reading comments on how easy
orion clustering is to set up we were confident we could promise the client
we would cluster orion without having tested it :(.
Now we are in the position that orion *is* clustering correctly *but only
the default-web-app*. It will not replicate session state for any other web
applications setup in the default-web-site.xml file. We followed the setup
instructions to the letter:
(NOTE: All of these steps were taken for both servers)
1) We tested our web app individually on our two test servers and they ran
correctly.
2) We added the <cluster-config/> tag to
orion/application-deployments/default/defaultWebApp/orion-web.xml.
According to the docs: "If you want to add clustering for the whole website
(for all web-applications), edit the orion-web.xml of the default
web-application...". We are using orion 1.4.5, so according to the docs ALL
of the web applications defined in default-web-site.xml should be clustered.
3)We added the cluster-island="1" to the default-web-site.xml file in the
<web-site> tag. Note that all the applications we are testing are defined
in the default-web-site.xml, ie:
<web-site host="ivan" port="8080" cluster-island="1" display-name="Default
Orion WebSite">
<frontend host="groovy" port="80" />
<default-web-app application="default" name="defaultWebApp" />
<web-app application="TestApp" name="TestApp-web" root="/TestApp" />
<web-app application="Test2" name="Test2-web" root="/Test2" />
Note that we also changed the 'host' attribute in the web-site tag from
[ALL] to our actual hostname.
4) As you can see from step 3) we added the frontend-host tag with the
location of the loadbalancer to the body of the <web-site> tag in
default-web-site.xml
5,6) We started the load balancer on our server named "groovy" then started
our other two servers. The lodablancer successfully noticed our other two
servers and added them to cluster island 1.
7) Lastly we tested the session replication using the
servlets/SessionServlet servlet. We modified the SessionServlet servlet,
adding one line that posts the ip of the server its being run from.
We then re-compiled the session servlet and to be safe, stopped the
loadbalnce, stopped both orion servers, restarted the load-balancer and both
servers (again, the load balancer found both servers).
We then ran SessionServlet and found the ip was from server2, we refreshed
the page until the counter went up to 5. We then shut down server2 and
refreshed again, and lo-and-behold the counter went up to 6! Yeah! We
thought we were done with clustering.
The Problem
We then copied the code for SessionServlet into a JSP called session.jsp.
We put the jsp in the TestApp-Web directory and tried the same test. THIS
time the counter went back to 1 when we ran it. This boggled us. We then
copied session.jsp into the directory orion/default-web-app and tried it.
IT WORKED!! We did not change a line of code.
This is an exact recreation of our problem with orion session replication.
We followed the docs exactly. If you have gotten clustering to work
properly, we would appreciate greatly if you could share your knowledge with
us. We are at an impasse and cannot figure out what to try next.
Just for completeness, here is our server.xml file, perhaps we are missing a
setting in this file(?)
...
<application-server
application-directory="../applications"
deployment-directory="../application-deployments"
>
<rmi-config path="./rmi.xml" />
<principals path="./principals.xml" />
<log>
<file path="../log/server.log" />
</log>
<global-application name="default" path="application.xml" />
<global-web-app-config path="global-web-application.xml" />
<web-site path="./default-web-site.xml" />
<application name="Test2" path="../applications/Test2/" auto-start="true"
/>
<application name="TestApp" path="../applications/TestApp/"
auto-start="true" />
...
Thanks for your help,
Michael N. Christoff
Developer, Eldan Software Ltd.
Toronto, ON, Canada
www.eldan.com
