Red Hat

Developer Materials

A SingletonService deployed in a JAR started by SingletonStartup and accessed by an EJB

What is it?

This example demonstrates the deployment of a Service that is wrapped with the SingletonService decorater to be a cluster wide singleton service.

The example is composed of 2 maven projects with a shared parent. The projects are as follows:

  1. service: This project contains the Service and the EJB code to instantiate, start and access the service
  2. client : This project contains a remote ejb client to show the behaviour

The root pom.xml builds each of the subprojects in the above order and deploys the archive to the server.

System requirements

The application this project produces is designed to be run on Red Hat JBoss Enterprise Application Platform 6.1 or later.

All you need to build this project is Java 6.0 (Java SDK 1.6) or later, Maven 3.0 or later.

Configure Maven

You can copy or link to the Maven configuration information in the README file in the root folder of the quickstarts. For example:

If you have not yet done so, you must Configure Maven before testing the quickstarts.

Start the JBoss Server with a HA profile

If you run a non HA profile the singleton service will not start correctly. To run the example one instance must be started, to see the singleton behaviour at minimum two instances should be started.

Start server one : standalone.sh --server-config=standalone-ha.xml -Djboss.node.name=nodeOne
Start server two : standalone.sh --server-config=standalone-ha.xml -Djboss.node.name=nodeTwo -Djboss.socket.binding.port-offset=100

Build and Deploy the Quickstart

NOTE: The following build command assumes you have configured your Maven user settings. If you have not, you must include Maven setting arguments on the command line. See Build and Deploy the Quickstarts for complete instructions and additional options.

  1. Make sure you have started the JBoss Server as described above.
  2. Open a command line and navigate to the root directory of this quickstart.
  3. Type this command to build and deploy the archive:

     mvn clean install jboss-as:deploy
    
  4. This will deploy service/target/jboss-cluster-ha-singleton-service.jar to the running instance of the server.
  5. Type this command to deploy the archive to the second server (or more) and replace the port, depending on your settings:

     mvn jboss-as:deploy -Djboss-as.port=10099
    
  6. This will deploy service/target/jboss-cluster-ha-singleton-service.jar to the running instance of the additional server.

  7. Check whether the application is deployed on each instance. All instances will have a message:

     INFO  [org.jboss.as.clustering.singleton] (SingletonService lifecycle - 1) JBAS010342: nodeOne/cluster elected as the singleton provider of the jboss.quickstart.ejb.ha.singleton service
     Only nodeOne (or even one instance) will have a message:
     INFO  [org.jboss.as.clustering.singleton] (SingletonService lifecycle - 1) JBAS010340: This node will now operate as the singleton provider of the jboss.quickstart.ejb.ha.singleton service
    
  8. The timer on the started node will log a message every 10sec.

Check the timer

  1. Open a command line and navigate to the root directory of this quickstart.
  2. Type the following command to start the client:

     cd client
     mvn exec:exec
    
  3. Check the output. The request to the EJB is running four times and every time it should respond:

     # The timer service is active on node with name = NodeOne   If you look in the server log files, you will see that each node will process requests
    
  4. Stop the server nodeOne. If you look into the server nodeTwo log file, you will see the message:

     JBAS010342: nodeTwo/cluster elected as the singleton provider of ..."   This shows that the singleton service was started. The timer will be started here and log a message every 10 seconds.
    
  5. Repeat step 2. The request is running four times and the message is:

     # The timer service is active on node with name = NodeTwo   If you look into the server #2 log file you will see that it process all four requests.
    

Undeploy the Archive

  1. Make sure you have started the JBoss Server as described above.
  2. Open a command line and navigate to the root directory of this quickstart.
  3. When you are finished testing, type this command to undeploy the archive:

     mvn jboss-as:undeploy
     mvn jboss-as:undeploy -Djboss-as.port=10099
    

Run the Quickstart in JBoss Developer Studio or Eclipse

You can also start the server and deploy the quickstarts from Eclipse using JBoss tools. For more information, see Use JBoss Developer Studio or Eclipse to Run the Quickstarts

Debug the Application

If you want to debug the source code or look at the Javadocs of any library in the project, run either of the following commands to pull them into your local repository. The IDE should then detect them.

mvn dependency:sources
mvn dependency:resolve -Dclassifier=javadoc

Recent Changelog

  • Nov 8, 2013(Sande Gilda):Bz1028448 Add spaces to end of metadata so it renders with a line break in HTML
  • Oct 7, 2013(Sande Gilda):Merge from master to 6.2.x for ER5
  • Sep 24, 2013(Sande Gilda):Remove references to JBoss AS 7 from the quickstarts
  • Sep 23, 2013(Sande Gilda):Update metadata source URLs to new repository
  • Sep 13, 2013(Sande Gilda):JDF 487 Remove as from quickstart artifactId and archive names and access URLs in README files
  • Jun 12, 2013(Sande Gilda):Modify README file internal links to use generated anchors. Remove hard coded anchors. Fixed obsolete links and other markdown rendering problems
  • Feb 13, 2013(Sande Gilda):Apply fixes made to EAP for bugs 910704 910732 910882
  • Feb 12, 2013(Sande Gilda):Add quickstart source repository of record to the README files
  • Jan 24, 2013(James Perkins):Use new property names for the maven plugin
  • Sep 11, 2012(Sande Gilda):Add target product https issues.jboss.org browse JDF 108
Avg:
Your Rating: