Oracle WebLogic Server Overview

• Is a Java EE application server hosting Java EE applications
• Is a completely compliant with Java EE 7
• Provides clustering for load balancing and high availability
• Offers an extensible security realm for authentication, authorization, and so on
• Runs the "Java components" of Oracle Fusion Middleware (FMW). These include Oracle SOA Suite, Oracle Service Bus, Oracle WebCenter Suite, and some Oracle Identity Management components
• Can control "System components" of FMW, such as Oracle HTTP Server (OHS), and Oracle Traffic Director (OTD).

System Architecture

• Clients using the World Wide Web to access applications.
• A firewall (hardware or software designed to prevent unauthorized access to or from a private network by using filtering or blocking ports)
• A cluster proxy of either a hardware load balancer or a web server like OHS
• A cluster of WebLogic Servers on various machines (each one running applications)
• Various back-end systems and databases accessed by the applications running on WebLogic Server

Other advanced architectural elements:

• Additional firewalls
• Multiple WebLogic Server clusters
• Multiple load balancers, or hardware load balancers in front of multiple web servers

WebLogic Server Domain

A domain is a collection of WebLogic Server resources. There are different kinds of resources in a domain, including WebLogic Servers, deployed applications, clusters, security providers, and Java Message Service and Java Database Connectivity elements.

All domains contain a special server called the administration server. The administration server is only used for domain configuration and manage all of the domain resources.

The other WebLogic Servers in the domain are called managed servers. In most domains, the applications are deployed to the managed servers. 

A single WebLogic Server product installation can be used to create and run multiple domains, or multiple product installations can be used to run a single domain. How domains are defined is up to you. You can define multiple domains based on different system administrators' responsibilities, application boundaries, or geographical locations of the machines on which servers run.

Managed Servers

A domain can have zero or more managed servers.

A managed server:

• Is managed by the administration server
• Is an instance of WebLogic Server and, therefore, a fully functional Java Enterprise Edition application server
• Is where your Java Enterprise Edition applications run
• Web applications, EJBs, web services, enterprise applications
• Can be clustered with other cooperating managed servers for availability, scalability, and automatic failover

Node Manager

• Is a WebLogic server utility, that enables us to start, stop, and restart both admin server and managed server instances from the remote location
• Monitors server availability and can restart failed servers
• Can be used to migrate servers on a failed machine to another machine
• Can also manage OHS, OTD, and OID components

Hope this article will be helpful.

In my upcoming article, I will cover the installation of Oracle WebLogic Server 12c.