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WebLogic: Cluster Adress option

Published on: 21 June 2013 Author: Michel Schildmeijer Category: Oracle

Although I haven’t had time lately to do some blogposting, I’d like to pick it up from here with short articles from which I hope you will learn some about the features of Oracle Fusion Middleware areas with special focus on WebLogic.

One of the things I often encounter is that there is a misconception about something called the ‘Cluster Address Option’ within a WebLogic Domain Configuration. So, what is it? Every time you configure a WebLogic Cluster, you can set several configurations for your cluster to facilitate the high availability of an application. One of those is the Cluster Address Option, which you find on the General Tab of you Cluster:

Format is : <mshost1:port>,<mshost2:port>, etc… Each entry corresponds to a Managed Server and port that received the request.

This is a static list for applications (EJB’s) to choose from. When not filled in, WebLogic generates in each request dynamically an adress.

My best practise is to fill in it in when you have an Oracle Service Bus cluster. The OSB configuration, but also the reportingprovider rely to the underlying entity and stateless beans to generate a hostname as part of a request URL for processing messages.

Another option is to fill in one Virtual hostname, that points to all available managed servers in the cluster, but be aware that in this case all managed servers should be set to the same listenport. If the request was received by a Managed Server, the listen address and port combinations in the cluster address reflect the ListenAddress and ListenPort values from the associated ServerMBean and/or SSLMBean instances.

The default number of the NumberOfServersInClusterAddress attribute on the ClusterMBean is 3. You can modify this value on the Environments—>Clusters—>ClusterName->Configuration->General

If there are fewer Managed Servers available in the cluster than the value of NumberOfServersInClusterAddress, the dynamically generated cluster address contains all available for each of the running Managed Servers.

If there are more Managed Servers available in the cluster than the value set in, WebLogic Server does a random select of the available managed servers in this value.

About the author Michel Schildmeijer

Michel started his career as a medical officer in the Royal Dutch Airforce, with a focus on pharma. After the air force, he continued in pharma, followed by time working in clinical pharmacology. While there, he transitioned to IT by learning UNIX and MUMPS, and developed a system for managing patients’ medical records. As his career developed, his responsibility shifted from a deep technical perspective to a more visionary role. At the end of 2011, Michel authored a book on WebLogic Administration for beginners. He joined Qualogy in April 2012 where he expanded his repertoire significantly, serving a wide range of customers with his knowledge about Java Application Servers, Middleware and Application Integration. He also increased his multiple-industry knowledge in his role as Solutions or IT architect by working for customers in a range of sectors, including financials, telecom, public transportation and government organizations. In 2012, he received the IT Industry-recognized title of Oracle ACE for being an ambassador and community leader in his area of expertise. In 2019, this was enhanced to Oracle ACE Director. Michel is asked regularly to speak about technology and the impact of innovation at national and international conferences such as KubeCon, Oracle OpenWorld, Groundbreakers Developers Tours and others. He contributes actively to the OpenSource community and solutions regarding containerization, CI/CD and DevOps. In October 2021, Michel took an exciting step in his career by becoming Business Unit Manager for Qualogy Managed Services. While he still has a finger on the pulse in terms of technology, he is expanding his scope by combining his experience with the new insights gained in his new position. Read more via blog: https://bit.ly/3fAxrqf | Medium: https://mschildmeijer.medium.com/ | Books: Oracle Weblogic Server 11gR1 PS2: Administration Essentials: https://bit.ly/3IhALmf | Oracle WebLogic Server 12c: First Look1: https://bit.ly/31olbpj