Weblogic Authors: Yeshim Deniz, Elizabeth White, Michael Meiner, Michael Bushong, Avi Rosenthal

Related Topics: Weblogic

Weblogic: Article

Developing Web Applications in a Clustered Environment Using WLST and Workshop

Developing Web Applications in a Clustered Environment Using WLST and Workshop

Now select wlst-createcluster in the left panel, as shown in Figure 6.

Figure 6: Looking at wlst-createcluster in External Tools

This screen specifies the name of the program to run (wlst.cmd), the Working Directory (wlst-workshop), and the arguments that will be passed to WLST (createcluster.py and myclusterdomain). The first argument passed to WLST is always the name of the script; subsequent argument(s) represent any inputs the script expects. In this case, the createcluster.py script expects the name of the domain, which I've named myclusterdomain. Click on the Run button at the bottom of the screen to create the domain.

At this point you've used Workshop and WLST to create an administration server and two managed servers, and placed the managed servers into a cluster.

Step 2: Start
In this step you start the clustered domain and then deploy the application to the cluster. These steps are analogous to those described in Part 1.

To start the cluster, select the program called wlst-startcluster in the External Tools panel. This will invoke the same script that ran in Part 1.

Similarly, to start the application first click on hello.html and bring it up in the main window. This will ensure that the right application is deployed. Then, select the program called wlst-deploy in the External Tools panel. This will invoke the deploy.py script, which deploys the helloApp application to the cluster.

In each case, you may need to adjust the parameters on the External Tools screen if you are not using the defaults. Note that the last parameter in the deploy arguments is http://localhost/hello.html. This will automatically invoke the browser with this URL. You can change this depending on your settings if not using the HTTP Server with port 80. At this point you've used WLST and Workshop to start the cluster and deploy the application to the cluster. Let's now run it!

Step 3: Run
Running the application is again identical to Part 1—just enter the appropriate URL into your browser (or use the browser that was invoked at the end of Step 2). Using Apache as a load balancer, type: http://localhost/hello.html.

Type in your name and click on Submit. Now, let's run the getstatus.py command from External Tools. This will tell you which server (ms1 or ms2) is serving the requests. Now, hit refresh on the browser, and then run getstatus again. Notice that the same server is invoked, using the same session.

Now, let's see what happens if one of your servers goes down. Let's kill the server (ms1 or ms2) that is serving these requests. To kill it, use the stopserver.py command from External Tools. Make sure to change ms1 to ms2 in the arguments window if you need to stop ms2. Now, hit the refresh button again. Notice two things:

  1. The request is now served by the other managed server (as can be observed by running the getstatus script).
  2. The session ID has changed!

The first behavior is desirable, as clustering is designed to enable high availability; in the event of a server crash, another server in the cluster should pick up the load. However, the second behavior may not be desirable, as you may expect the surviving managed server to use the same session as was used by the first server. This is what is known as session replication. So what happened here?

What you need to do is configure the application to use session persistence. Bring up the helloApp application in Workshop, and edit the weblogic.xml file, which is located under the WEB-INF directory. You need to add the following snippet to enable session replication:


The default setting (persistent store type of memory) does not replicate session across clustered servers. Setting the parameter above to replicated allows sessions to be replicated across servers in a cluster. Therefore, when the managed server serving the session goes down, the surviving server takes over the sessions. The end user continues working as if there was no system failure.

Now, restart the failed managed server by running wlst-startserver from External Tools, and then redeploy helloApp by executing wlst-redeploy.

Now, retry the above experiment. You'll see that when the surviving server takes over, it uses the same session ID!

You've now used Workshop with WLST to create a fully functional clustered environment for testing the application. You can now iteratively make changes to the application, redeploy the application to the cluster, and test. The Workshop and the WLST scripts provided here do all the hard work, so you as a developer can focus on your application and quite easily test in a clustered environment.

The Big Picture
In this article I focused on developer productivity, and in particular, how developers can test their applications in a clustered environment, facilitating easy testing. Once the developer has completed the development phase (with sufficient unit/cluster testing), the application is typically handed off to other teams for different stages, such as: integration, QA/staging, and production. WLST can also be leveraged in these stages to automate domain and application provisioning and further reduce the time required to deliver the application into production. For more information on how WLST can be leveraged in these stages, see Automating WebLogic Platform Application Provisioning: A Case Study (Dev2Dev, August 2005).

As applications move through the lifecycle stages from development to production, the environments become increasing more complex at each stage. One such area of complexity is clustering. Since developers typically test exclusively in a single-server environment, the chances of encountering problems in later stages is increased. By providing the means for developers to try their applications in a cluster with minimal overhead, many of these problems can be fixed early in the lifecycle of the project.

This tutorial presented the means for developers to run their applications in a clustered domain. By leveraging the power of WLST and Workshop, I was able to show how developers can create, deploy, and start their applications right from the same environment they use to develop and run the application on a single-server domain. Giving this power to developers will shorten the project life cycle and enable projects to be more rapidly deployed into production.

The sample code used in this article can be downloaded here.


  • WLST Project home on CodeShare - Scripts and utilities using WLST Offline and/or WLST Online
  • WLST Command and Variable Reference (product documentation) - Description of WLST commands and variables in details
  • Dev2Dev's BEA Workshop Product Center - for related material and downloads
  • Understanding Cluster Configuration and Application Deployment (product documentation) - information that defines how the configuration of a cluster is stored and maintained
  • Failover and Replication in a Cluster (product documentation) - how WebLogic Server detects failures in a cluster, and how failover is accomplished
  • Using Node Manager to Control Servers (product documentation) - describes Node Manager functionality, architecture, and configuration procedures
  • Apache HTTP Server - a secure, efficient and extensible server that provides HTTP services in sync with the current HTTP standards
  • WebLogic Apache HTTP Plug-in ( product documentation) - describes how to install and configure the Apache HTTP Server Plug-In
  • Automating WebLogic Platform Application Provisioning: A Case Study by Andy Lin, showing more complex provisioning scenarios (Dev2Dev, August 2005)
  • More Stories By Michael Meiner

    Michael Meiner is an Engineering Director at Oracle Corporation. His organization is responsible for lifecycle Quality Assurance of the Fusion Middleware Suite of products, including: installation, configuration, upgrade, test-to-production and interoperability on a range of computing platforms and Operating Systems. The Fusion Middleware product suite supports both On-Premise as well as Cloud offerings.

    Comments (0)

    Share your thoughts on this story.

    Add your comment
    You must be signed in to add a comment. Sign-in | Register

    In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.

    @ThingsExpo Stories
    Leading companies, from the Global Fortune 500 to the smallest companies, are adopting hybrid cloud as the path to business advantage. Hybrid cloud depends on cloud services and on-premises infrastructure working in unison. Successful implementations require new levels of data mobility, enabled by an automated and seamless flow across on-premises and cloud resources. In his general session at 21st Cloud Expo, Greg Tevis, an IBM Storage Software Technical Strategist and Customer Solution Architec...
    Nordstrom is transforming the way that they do business and the cloud is the key to enabling speed and hyper personalized customer experiences. In his session at 21st Cloud Expo, Ken Schow, VP of Engineering at Nordstrom, discussed some of the key learnings and common pitfalls of large enterprises moving to the cloud. This includes strategies around choosing a cloud provider(s), architecture, and lessons learned. In addition, he covered some of the best practices for structured team migration an...
    Product connectivity goes hand and hand these days with increased use of personal data. New IoT devices are becoming more personalized than ever before. In his session at 22nd Cloud Expo | DXWorld Expo, Nicolas Fierro, CEO of MIMIR Blockchain Solutions, will discuss how in order to protect your data and privacy, IoT applications need to embrace Blockchain technology for a new level of product security never before seen - or needed.
    Imagine if you will, a retail floor so densely packed with sensors that they can pick up the movements of insects scurrying across a store aisle. Or a component of a piece of factory equipment so well-instrumented that its digital twin provides resolution down to the micrometer.
    In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settle...
    BnkToTheFuture.com is the largest online investment platform for investing in FinTech, Bitcoin and Blockchain companies. We believe the future of finance looks very different from the past and we aim to invest and provide trading opportunities for qualifying investors that want to build a portfolio in the sector in compliance with international financial regulations.
    No hype cycles or predictions of a gazillion things here. IoT is here. You get it. You know your business and have great ideas for a business transformation strategy. What comes next? Time to make it happen. In his session at @ThingsExpo, Jay Mason, an Associate Partner of Analytics, IoT & Cybersecurity at M&S Consulting, presented a step-by-step plan to develop your technology implementation strategy. He also discussed the evaluation of communication standards and IoT messaging protocols, data...
    Coca-Cola’s Google powered digital signage system lays the groundwork for a more valuable connection between Coke and its customers. Digital signs pair software with high-resolution displays so that a message can be changed instantly based on what the operator wants to communicate or sell. In their Day 3 Keynote at 21st Cloud Expo, Greg Chambers, Global Group Director, Digital Innovation, Coca-Cola, and Vidya Nagarajan, a Senior Product Manager at Google, discussed how from store operations and ...
    In his session at 21st Cloud Expo, Raju Shreewastava, founder of Big Data Trunk, provided a fun and simple way to introduce Machine Leaning to anyone and everyone. He solved a machine learning problem and demonstrated an easy way to be able to do machine learning without even coding. Raju Shreewastava is the founder of Big Data Trunk (www.BigDataTrunk.com), a Big Data Training and consulting firm with offices in the United States. He previously led the data warehouse/business intelligence and B...
    "IBM is really all in on blockchain. We take a look at sort of the history of blockchain ledger technologies. It started out with bitcoin, Ethereum, and IBM evaluated these particular blockchain technologies and found they were anonymous and permissionless and that many companies were looking for permissioned blockchain," stated René Bostic, Technical VP of the IBM Cloud Unit in North America, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Conventi...
    A strange thing is happening along the way to the Internet of Things, namely far too many devices to work with and manage. It has become clear that we'll need much higher efficiency user experiences that can allow us to more easily and scalably work with the thousands of devices that will soon be in each of our lives. Enter the conversational interface revolution, combining bots we can literally talk with, gesture to, and even direct with our thoughts, with embedded artificial intelligence, whic...
    When shopping for a new data processing platform for IoT solutions, many development teams want to be able to test-drive options before making a choice. Yet when evaluating an IoT solution, it’s simply not feasible to do so at scale with physical devices. Building a sensor simulator is the next best choice; however, generating a realistic simulation at very high TPS with ease of configurability is a formidable challenge. When dealing with multiple application or transport protocols, you would be...
    Smart cities have the potential to change our lives at so many levels for citizens: less pollution, reduced parking obstacles, better health, education and more energy savings. Real-time data streaming and the Internet of Things (IoT) possess the power to turn this vision into a reality. However, most organizations today are building their data infrastructure to focus solely on addressing immediate business needs vs. a platform capable of quickly adapting emerging technologies to address future ...
    We are given a desktop platform with Java 8 or Java 9 installed and seek to find a way to deploy high-performance Java applications that use Java 3D and/or Jogl without having to run an installer. We are subject to the constraint that the applications be signed and deployed so that they can be run in a trusted environment (i.e., outside of the sandbox). Further, we seek to do this in a way that does not depend on bundling a JRE with our applications, as this makes downloads and installations rat...
    Widespread fragmentation is stalling the growth of the IIoT and making it difficult for partners to work together. The number of software platforms, apps, hardware and connectivity standards is creating paralysis among businesses that are afraid of being locked into a solution. EdgeX Foundry is unifying the community around a common IoT edge framework and an ecosystem of interoperable components.
    DX World EXPO, LLC, a Lighthouse Point, Florida-based startup trade show producer and the creator of "DXWorldEXPO® - Digital Transformation Conference & Expo" has announced its executive management team. The team is headed by Levent Selamoglu, who has been named CEO. "Now is the time for a truly global DX event, to bring together the leading minds from the technology world in a conversation about Digital Transformation," he said in making the announcement.
    In this strange new world where more and more power is drawn from business technology, companies are effectively straddling two paths on the road to innovation and transformation into digital enterprises. The first path is the heritage trail – with “legacy” technology forming the background. Here, extant technologies are transformed by core IT teams to provide more API-driven approaches. Legacy systems can restrict companies that are transitioning into digital enterprises. To truly become a lead...
    Digital Transformation (DX) is not a "one-size-fits all" strategy. Each organization needs to develop its own unique, long-term DX plan. It must do so by realizing that we now live in a data-driven age, and that technologies such as Cloud Computing, Big Data, the IoT, Cognitive Computing, and Blockchain are only tools. In her general session at 21st Cloud Expo, Rebecca Wanta explained how the strategy must focus on DX and include a commitment from top management to create great IT jobs, monitor ...
    "Cloud Academy is an enterprise training platform for the cloud, specifically public clouds. We offer guided learning experiences on AWS, Azure, Google Cloud and all the surrounding methodologies and technologies that you need to know and your teams need to know in order to leverage the full benefits of the cloud," explained Alex Brower, VP of Marketing at Cloud Academy, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clar...
    The IoT Will Grow: In what might be the most obvious prediction of the decade, the IoT will continue to expand next year, with more and more devices coming online every single day. What isn’t so obvious about this prediction: where that growth will occur. The retail, healthcare, and industrial/supply chain industries will likely see the greatest growth. Forrester Research has predicted the IoT will become “the backbone” of customer value as it continues to grow. It is no surprise that retail is ...