Clustering dm-server instances

Hi,

Is there some documentation and examples on how to cluster dm-server instances? Not looking for something complex. A simple round-robin with sticky session would do a trick.

Is all of this based on tomcat support?

There is no dm Server documentation or examples for how to do it as it should be identical to standard Tomcat clustering.

Hi,
I am trying to configure clustering in spring dm 2.0 .
As per user documentation of Spring DM 2.0 : "SpringSource dm Server supports standard Apache Tomcat cluster configuration."
I was able to do clustering of Apache tomcat 6.0 using Apache web server + mod_jk.Similar steps not working with spring DM server.
Can you guys provide any documentation or steps for clustering spring DM??

Abhinav Mishra

That is not something we have documented. Please refer to Tomcat documentation. What problem symptoms are you seeing?

I was able to achieve clustering using tomcat-6.
Site I followed to do that : http://www.easywayserver.com/impleme...clustering.htm

As I mentioned earlier I used Apache web server + mod_jk to do clustering.
In Apache Web Server we need to configure \Apache\conf\workers.properties file that holds information about nodes.
content of worker.properties for tomcat clustering :

workers.tomcat_home=/tomcatA
workers.java_home=$JAVA_HOME
ps=/
worker.list=tomcatA,tomcatB,loadbalancer

worker.tomcatA.port=8109
worker.tomcatA.host=localhost
worker.tomcatA.type=ajp13
worker.tomcatA.lbfactor=1

worker.tomcatB.port=8209
worker.tomcatB.host=localhost
worker.tomcatB.type=ajp13
worker.tomcatB.lbfactor=1

worker.loadbalancer.type=lb
worker.loadbalancer.balanced_workers=tomcatA,tomca tB
worker.loadbalancer.sticky_session=1

When we can point to the port where apache web server is running(80 in my case) and try to access resource which are available in nodes(I did Vertical Clustering).
I think the problem is with missing webapps folder in case of Spring DM server.
Need you guys help to resolve this issue.

Thanks in Advance !!!

Abhinav Mishra

Please could you describe the symptoms you are seeing. We need something more specific than "it doesn't work" if we are to give you ideas to help you make progress. :-)

Thanks for reply :)
I will try to explain what All I did for Spring DM clustering.
I installed Apache Web Server and which runs on port 80.
In the same folder(installation) I put two instance of Spring DM server(2.0.1).
I downloaded mod_jk and put it with other shared objects for Apache Web Server.
I changed \Apache\conf\worker.properties file.Content of that file I already put(Please check below thread.
I modified \SpringDM1-2\config\tomcat-server.xml and com.springsource.kernel.properties for port.
Spring DM 1 : on port 8080 and 2401(DM Shell)
Spring DM 2 : on port 8081 and 2402(DM Shell)
After that I created one web bundle and deploy it on both the Spring DM server.
http://localhost:80 : works fine
http://localhost:8080/testCluster/index.jsp : works fine
http://localhost:8081/testCluster/index.jsp : works fine

http://localhost:80/testCluster/index.jsp : doesn't work
Error in \Apache\logs\error.log
[client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/testCluster
[Wed Apr 21 17:34:36 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/testCluster
[Wed Apr 21 17:34:36 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/testCluster
[Wed Apr 21 17:34:45 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/testCluster
[Wed Apr 21 17:34:46 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/testCluster
[Wed Apr 21 17:34:47 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/testCluster
[Wed Apr 21 17:34:52 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/testCluster
[Wed Apr 21 17:34:56 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/testCluster
[Wed Apr 21 17:35:01 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp
[Wed Apr 21 17:35:08 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp
[Wed Apr 21 17:35:09 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp
[Wed Apr 21 17:35:10 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp
[Wed Apr 21 17:36:29 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp
[Wed Apr 21 17:36:30 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp
[Wed Apr 21 17:36:31 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp
[Wed Apr 21 17:36:32 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp
[Wed Apr 21 17:36:32 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp
[Wed Apr 21 17:36:32 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp
[Wed Apr 21 17:36:33 2010] [error] [client 127.0.0.1] File does not exist: E:/server/cluster/Apache/htdocs/index.jsp

It looks like Apache web server is not able to recognize the DM nodes.However similar setup works perfectly fine with Tomcat 6.
Please provide your input/suggestions.

Abhinav Mishra

I think your conclusion is right. The Apache web server is not configured properly to farm out across the cluster of dm Server instances.

Please can you confirm that you did not change the Apache web server or its configuration. I would have thought that it could farm out across dm Server instances equally easily as across Tomcat instances because from a HTTP protocol point of view, what's the difference?

If you confirm this, then there must be something peculiar going on with mod_jk. Did you in some way try to point it at the dm Server directories as that is unlikely to work?

Perhaps you could try configuring the Apache web server manually to avoid its Tomcat dependency?

You might also take a look at mod_proxy which could be easier to configure than mod_jk.

Abhinav, May I ask you to update us with your current status? I am really concerned about it. I am using Spring Framework, Spring Security & Hibernate all v3.x. (I was about to give it up & switch all my architecture to completely different alternatives as I thought that Spring has no out of the box clustering support. But fortunately it seems I am wrong :) )