WebLogic Server Terminologies

What is domain?
The logically related group of WebLogic server instances managed from single set of configuration artifacts. DOmian will have the servers and the clusters.


What is server?
It is the configured instance to host applications and resources. Server can be managed server or administraton server.



What is admin server?
One domain will have one administration server. It will have the administration console. From the administration console we can start and stop the servers.



What is Managed Server?
Each managed server is independent of other managed servers. There can be multiple managed servers in a domain. Managed servers are managed by the administration server. Each managed server will have the local copy of the configuration. Managed server and the administration server will be in sync. If you make any changes to the managed server from the administartation server then that configuration will be moved to the Managed server.


What is Cluster?
The group of managed servers running simultaneously in a domain is called as Cluster. There can be multiple clusters in a single domain. All the servers within the cluster have to be at the same Maintenance pack level. The clustered servers can be in the same or different machines.

What is Node Manager?
It is not associated with any domain. It is the utility running on the server which enables to start ,stop and restart the server. It is required for the server Migration


What is Machine?
Machine is piece of hardware. In a machine we can have the multiple managed servers

Administration tools
1. Configuration Wizard. : For creating the domains
2. Administration console : Complete administatration of the server is involved here.We can monitor dmains,deploy the applications and control the servers.The operation that can be performed on the admin console can be performed in the WLST i,e WebLogic Scripting Tool
Along with these we can use the command line tools for the deployment.
Weblogic.Deployer.

Conclusion

The best practice is to have the each manged server in its own physical server.Each application will have its own domain. Even the admin server have to be in its own phusical server.