WebLogic Architecture: Understanding the Domain Structure

A WebLogic domain is a fundamental administrative unit for WebLogic Server. It comprises one or more WebLogic Server instances with their resources, which are collectively managed and configured using a single Administration Server. The WebLogic server architecture features a multitier structure, where various server instances within a domain play specific roles, ensuring efficient management and deployment of enterprise applications.

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WebLogic Server instances are referred to as Managed Servers, in which Java Enterprise Solutions are deployed. These Managed Servers could be grouped into clusters for load balancing and failover, especially for critical applications. Multiple WebLogic domains could also be set up according to application boundaries, system administrator responsibilities and server’s geographical location. Another alternative is to set up a single domain to manage all WebLogic Server administration activities. The weblogic server installation process involves setting up at least one server instance, and often includes multiple instances across separate servers, grouped into WebLogic domains for management and scalability.

The WebLogic domain infrastructure consists of three parts, as illustrated below:

• Administration Server: Guides the actions of managed servers
• Managed Servers: Stand-alone servers ruled by the Administration Server
• Clusters: Groups of managed servers managed by the Administration Server

Sample WebLogic Domain Infrastructure

Source: http://docs.oracle.com/cd/E21764_01/web.1111/e14140/intro.htm – WLDCW101

The sample configuration illustrated above comprises one Administration Server, two Managed Servers that are not within a cluster, and two clusters each with several Managed Servers.

Below is the outline of the WebLogic domain infrastructure:

Administration Server: Each WebLogic domain must have one server instance set as the Administration Server. This server performs all the configuration changes of the domain and deployment of applications. The Administration Server centralizes domain management and access provision for all the WebLogic Server administration tools listed below:

• Console: This is the Administration Server’s GUI.
• Security
• Application Deployment
• Domain connectivity

Managed Servers: These are all server instances that exist in a WebLogic domain apart from the Administration Server. They host application resources and components that are deployed and managed as part of the domain. In a WebLogic domain with only one server, that server will be used as both the Administration Server and the Managed Server.

Clusters: A Cluster is more than one Managed Server grouped together to provide high availability and scalability for applications. Clustering is important to provide failover whenever a server instance is unavailable. Clustered servers can be run on one machine or multiple machines, but clients perceive the cluster as one single WebLogic Server instance. The weblogic server cluster enables scaling and high availability, ensuring that client requests are efficiently handled and that application performance remains robust even in the event of server failures.

The WebLogic infrastructure offers a single, high-performance, highly integrated, and reliable database management solution. WebLogic Domain provides a single development and runtime environment that combines common application infrastructure with user-friendly robust management and an application development framework for portal initiatives, custom development and enterprise application integration.

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Introduction to WebLogic Domain

A WebLogic domain is a fundamental administrative unit for WebLogic Server, consisting of one or more WebLogic Server instances with their resources. Managed and configured using a single Administration Server, a WebLogic domain ensures streamlined management and deployment of applications. WebLogic Server instances, known as Managed Servers, can be grouped into clusters to facilitate load balancing and failover, enhancing the reliability and scalability of critical applications. Depending on application boundaries, system administrator responsibilities, and server’s geographical location, multiple WebLogic domains can be established. Alternatively, a single domain can be set up to manage all WebLogic Server administration activities, providing a centralized approach to administration and configuration.

Oracle Fusion Middleware Overview

Oracle Fusion Middleware is a comprehensive software suite that includes WebLogic Server, Oracle SOA Suite, Oracle Service Bus, and other products. It provides a standards-based software platform for developing, deploying, and managing enterprise applications. By leveraging Oracle Fusion Middleware, organizations can create a service-oriented architecture (SOA) that seamlessly integrates disparate applications, services, and systems. WebLogic Server, a key component of Oracle Fusion Middleware, offers a robust and scalable platform for deploying Java EE applications, ensuring high performance and reliability for enterprise solutions.

Application Server Architecture

The architecture of WebLogic Server is composed of several critical components, including the Administration Server, Managed Servers, and Node Manager. The Administration Server acts as the central management point for the domain, offering capabilities such as configuration management, monitoring, and security. Managed Servers, which can be configured to provide similar capabilities as the Administration Server, host the application resources and components deployed within the domain. The Node Manager, a utility that can run a WebLogic domain successfully, operates independently of the domain itself. WebLogic Server also provides a range of essential services, including Java Database Connectivity (JDBC), Java Message Service (JMS), and Java Transaction API (JTA), facilitating robust database connectivity, messaging, and transaction management.

Java EE and Web Services

WebLogic Server is a Java EE-compliant application server, supporting the latest Java EE standards and specifications. It provides a robust and scalable platform for deploying Java EE applications, including web services, Enterprise JavaBeans (EJBs), and JavaServer Pages (JSPs). With its support for web services, WebLogic Server enables developers to create and deploy web services using industry standards such as SOAP, WSDL, and UDDI. Java EE applications deployed on WebLogic Server benefit from its robust security, scalability, and reliability features, making it an ideal choice for enterprise-grade solutions.

Business Logic and Access Services

WebLogic Server offers a comprehensive range of services for implementing business logic and accessing data. The EJB container provides a managed environment for deploying Enterprise JavaBeans (EJBs), which can be used to implement business logic and access services. WebLogic Server supports various types of EJBs, including Entity Beans, Session Beans, and Message-Driven Beans (MDBs). Additionally, WebLogic Server supports Java EE connectors, enabling developers to access and integrate with external systems and services. The server also provides a range of access services, such as JDBC for database connectivity, JMS for messaging, and JTA for transaction management, ensuring seamless data access and manipulation across different formats and locations.