Oracle Web Logic Server (WLS) Overview

Domain:

•          A logically related group of WebLogic Server instances that you manage from a single set of configuration artifacts.

A Domain has:

•          Servers

•          Clusters of servers

 Server:

•          A configured instance to host applications and resources

•          WebApps, Enterprise Apps, Web Services, …

•          JMS, JDBC, Diagnostics, …

Server types are:

•          Administration Server :

       Central configuration controller for the entire domain.

Hosts the Administration Console

Enables you to start and stop servers from a central location

Enables you to migrate servers and services within the domain

Enables you to deploy applications within the domain

•          Managed Server :

                     

 A running instance that hosts applications and resources needed by those applications - The real work horses in a WebLogic domain

Each Managed Server is independent of all other Managed Servers in the domain (unless they are in a cluster, defined later)

You can have as many Managed Servers in a domain as you need

Individual Managed Servers are typically added for capacity and application isolation

Cluster:

•          A cluster is a group of Managed Servers running simultaneously and working together to provide increased scalability and reliability

•          Scalability: through parallelism

•          Reliability/Availability: through replication and redundancy

•          A cluster appears as a single instance to most clients.

•          Clusters enable some advanced features, such as Whole Server Migration, Service Migration, and clustered JMS destinations.

  

Node Manager:

•          Utility/process running on a physical server that enables you to start, stop, suspend, and restart WebLogic Server instances remotely

•          Must run on each physical server that hosts WebLogic Server instances that you want to control with Node Manager

•          Not associated with a domain. Can start any server instance that resides on the same physical server.

•          Optional, but required to start/stop servers using the Administration Console

•          Required for Whole Server Migration and for some configurations of Automatic Service Migration

 Machine:

•          A definition that identifies a particular, physical piece of hardware.

•          A machine definition is used to associate a computer with the Managed Servers it hosts.

•          Used by Node Manager in restarting a failed Managed Server

•          Used by a clustered Managed Server in selecting the best location for storing replicated session data

  

Configuration files:

•          config.xml – central configuration file for a domain

•          includes the configuration of each server instance, cluster, resource, and service in the domain.

•          references additional XML files that are stored in subdirectories of the domain/config directory: JMS, JDBC, WLDF, and Security

•          All files are based on schemas

 Administration Tools:

•          Configuration Wizard

•          GUI/scriptable tool to create and extend WebLogic domains

•          Template based

•          Administration Console

•          Browser-based tool for configuring and monitoring domains, deploying applications, and controlling servers

•          WebLogic Scripting Tool (WLST)

•          Script or command line tool to do the same thing as the Administration Console and Configuration Wizard

•          Note that we will cover details on WLST in a separate document

•          weblogic.Admin

•          Deprecated command line tool for configuring a domain

•          Recommend using WLST instead

•          weblogic.Deployer

•          Command line tool for deploying applications

  

Note:

•          WebLogic Server configuration is segmented by domain

•          Each domain represents a configuration entity and uses one set of configuration artifacts

•          Each domain has one Administration Server, and can have multiple managed servers and clusters

•          Node Manager is a per-machine process used to start and stop WebLogic Server instances

•          There are a number of administration tools available for configuring and managing a WebLogic domain:

•          Config Wizard, Admin Console, WLST, weblogic.Deployer