As Published In
Oracle Magazine
November/December 2011

TECHNOLOGY: Inside OCP

  

Certify Your Expertise


By TJ Palazzolo

 

Test your Oracle WebLogic Server mettle, and gain valuable credibility.

Oracle WebLogic Server Standard Edition application server technology implements the latest Java Platform, Enterprise Edition (Java EE) standards and offers choice in development frameworks and tooling. Oracle WebLogic Server Enterprise Edition includes all the features and benefits of Oracle WebLogic Server Standard Edition plus proven clustering technology, cross-domain management, and comprehensive diagnostic tooling. With the flexibility and variety of features built into Oracle WebLogic Server products, certification is a valuable way to validate the expertise of Oracle WebLogic Server system administrators.

Oracle now offers IT professionals the opportunity to earn the Oracle Certified Associate: Oracle WebLogic Server 11g System Administrator certification. To receive this recognition, a candidate must achieve a passing score on the Oracle WebLogic Server 11g: System Administration I exam. This exam addresses all Oracle WebLogic Server core job tasks, from basics such as installation, creating domains, starting servers, and deployment to the configuration of more-advanced infrastructure features such as clustering, datasources, and messaging.

This column utilizes sample questions to review Oracle WebLogic Server concepts and capabilities and also to help provide some insight into the types of questions you can expect to see on the Oracle WebLogic Server 11g: System Administration I exam.

Node Manager

A single physical environment, or “machine,” can host one or more Oracle WebLogic Server instances, each of which is a Java Virtual Machine process. Although you can start and stop these individual server processes by using scripts from the command line, you can also run a separate dedicated process using Oracle WebLogic Server’s Node Manager, which facilitates the starting and stopping of servers from a remote location. Depending on how you have configured Node Manager, you can issue these remote start and stop commands from either Oracle WebLogic Server’s Administration Console, a script using Oracle WebLogic Server’s WebLogic Scripting Tool, or a Secure Shell (SSH) session.

Which two statements about Node Manager are true?

a. By default, Node Manager binds to port 5556.

b. Each cluster is assigned a separate Node Manager process.

c. Node Manager cannot be used to start an administration server.

d. You must create a nodemanager.properties file to run Node Manager.

e. You can configure Node Manager to automatically restart a failed server.

The correct answers are A and E. 

Unless overridden in the nodemanager.properties file or from the command line, a Node Manager process listens for commands on port 5556. And by default, if a Node Manager process starts a server and the process later fails, Node Manager will attempt to restart it.

Answer B is incorrect because a Node Manager process always has a one-to-one relationship with a machine, not a cluster. Answer C is incorrect because you can certainly use Node Manager to remotely control both admin and managed servers. And finally, answer D is incorrect because even though Node Manager does, in fact, require a nodemanager.properties file, you do not need to explicitly create one. If one is not found, Node Manager will generate one.

Session Persistence

Applications often keep working data in server memory. Consider application users adding items to shopping carts. If the server running the application fails, all users on that server will lose this “session” data by default. For applications running in a cluster, however, Oracle WebLogic Server supports various session persistence options for avoiding such application failure scenarios.

The most commonly used session persistence option is in-memory replication, which ensures that each user session is automatically backed up on one other server in the cluster. After a server failure, application users are redistributed to the remaining servers, which can then obtain the backup copy of each user session.

Identify two tasks required for successful use of Oracle WebLogic Server in-memory replication for a Web application.

a. Add the persistence.xml file to the application.

b. Configure a Web proxy that supports session cookies.

c. Configure the cluster for multicast communication.

d. Deploy a JDBC datasource to the cluster.

e. Deploy the application to a cluster.

The correct answers are B and E.

For in-memory replication to function as designed, users should be redirected to the same server whenever possible. In-memory replication does this by using an intermediate proxy (hardware or software) and cookies to map users to their preferred servers. Answer E is also correct in that replication features are available only to clusters, not to individual servers.

Answer A is incorrect because even though you must use a deployment descriptor file to enable session persistence for an application, the correct file is weblogic.xml, not persistence.xml. Similarly, answers C and D are both valid Oracle WebLogic Server activities, but neither multicast communication nor a JDBC datasource is required for in-memory replication. Note, however, that other types of session persistence do require a datasource for accessing a relational database.

Deployment Plans

Next Steps


LEARN more about
 the Oracle Certification Program
 Oracle Certified Associate: Oracle WebLogic Server 11g System Administrator

 READ Inside OCP columns

Suppose you have an application running on Oracle WebLogic Server that requires a JDBC datasource referenced in the application’s deployment descriptor files. You want to first deploy this application to a test environment and then deploy it to the final production environment. However, for some reason, the JDBC datasources in these two environments use different names. Java EE deployment plans provide an elegant solution to this common dilemma. A deployment plan is a file, residing outside of the application, that you associate with the application at deployment time. A plan can augment and even override configuration settings in the application’s descriptors. But where do these plans come from?
 

Identify three ways to create a deployment plan.

a. Edit an application’s settings from the Oracle WebLogic Server Administration Console.

b. Run the Plan Generator command-line tool.

c. Enable the script generator in the Administration Console.

d. Author an XML file by hand.

e. Run the Oracle WebLogic Server Deployer tool.

The correct responses are A, B, and D. The easiest way to create and update a deployment plan is through the Administration Console. The Plan Generator (weblogic.PlanGenerator) command-line tool can also create a deployment plan. And, of course, you can alternatively create a deployment plan with a text editor. 

The reason answer C is incorrect is that although the Administration Console does include a feature that can record WebLogic Scripting Tool scripts based on your activities, it does not produce deployment plans. And answer E is incorrect because even though you can certainly use the Deployer command-line tool to associate a deployment plan with an application, it cannot create the plan file.


TJ Palazzolo is a senior principal curriculum developer at Oracle who creates educational and certification content for Oracle’s middleware products.


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