What is domain,Administration Server ,Managed Server and Node Manager

What is domain in WebLogic ?

Domain is logical grouping of resources and services and consist of Administration Server, Managed Server and cluster.  There can only be one administration Server in domain and zero to N Managed Server.

What is Administration Server ?

Administration Server is WebLogic Server instance that maintains configuration data for a domain. You can deploy your application on administration Server but it is recommended to create managed Server and deploy your application in managed server and leave Administration domain for configuration and maintenance.

—There will always be atleast one Administration Server in a domain.

What is Managed Server ?

Any WebLogic Server instance apart from Administration Server is called asManaged Servers. This is weblogic server where you deploy your application (Though you can deploy your application in Administration server as well but it is not recommended in production/UAT instance)

What is Cluster in WebLogic ?

Group of WebLogic Managed Server Instances that work together to provide high availability and scalability for applications is called cluster. WebLogic Servers with in cluster can run on same machine or different machines. These are also called as managed Server cluster.

Start WebLogic Domain

Once you have successfully created domain, next step is to  start weblogic domain and access Administration Console. (Steps here are to start basic domain – only one Administration Server,  “Start/Stop WebLogic Server - Administration and Managed Server“

Startup Script$BEA_HOME/user_projects/domain//bin/startWebLogic.sh (Unix)
$BEA_HOME\user_projects\domain\\bin\startWebLogic.cmd(Windows)

I installed domain with name base_domain and my BEA_HOME is c:\bea hence to start my domain -
c:\bea\user_projects\ domains\ base_domain\ bin\ startWebLogic.cmd

Node Manager is Weblogic Server utility to start, stop and restartAdministration and Managed Server Instances from remote location.

1. Node Manager Process is associated with a Machine and NOT with specific Weblogic Domain (i.e. Use one node manager for multiple domains on same machine)

2. There are two versions of Node Manager - Java-based and Script-based

Java-based node manager – runs with in JVM (Java Virtual Machine) Process and more secure than script-based node manager. Configuration for java-based node manager are stored in nodemanager.properties

Script-based node manager – is available for Linux and Unix systems only and is based on shell script.

3. There are multiple ways to access Node Manager
- From Administration Console : Environments -> Machines -> Configuration -> Node Manager
- JMX utilities (Java Management eXtension)
- WLST commands (WebLogic Scripting Tool)