Chapter 06: Configuring a Weblogic Domain

Friends!!, In the last chapter we learnt how to install weblogic server binaries on a linux OS platform. Further to that, We need to learn how to configure a weblogic domain.

In this chapter I will show you how to configure a very basic domain with just having an Admin Server and slowly as we move to the next chapters, I will be explaining you the other important and advance topics wrt Domain ...

Configuration wizard allows you to create a new domain or extend an already existing domain. The best example of extending a domain is adding a new server on a remote machine and configuring a cluster.

Before starting with the weblogic configuration wizard, lets first understand few basic concepts related to domain.

What is a weblogic domain ?

• Weblogic domain is a logical entity which groups logically related Servers and allows you to manage them from a single set of configuration.


• A Weblogic  domain can contain ZERO to N number of managed servers and ONE Admin Server that is a domain must have only one admin server., without an Admin Server you cannot configure a domain.


• It may contain individual servers or cluster of servers


• NOTE: All WebLogic Server instances within the same domain must be at the same major and minor version.


• A domain looks like as below:

• You can see in the above pic that the domain contains few individual servers and a group of servers withing a cluster.


• Domain can be spanned across number of physical servers (hosts) depending upon the business need.

What is a Server ?

• A Server in Weblogic domain is an instance which you configure and can host applications and other resources such as Enterprise Apps, WebApps,Web Services, JDBC, JMS ...etc


• There are 2 types of servers, one is Admin Server and the other type is called as Managed Server.

What is an Admin Server ?

• Admin Server maintains the configuration information of your entire domain.


• This is the server where your "Admin Console" gets deployed.


• It provides you the power to start/stop/restart/monitor the servers of the domain (cluster or non-clustered) from a single URL that is admin console. (You need to understand the concept of Nodemanager as well to be more clear on ho start/stop/restart of servers running on a remote machine is possible using admin server/console...I will describe it in the following section)


• It also enables you to deploy/undeploy applications on the servers within the domain.


• Allows you to configure services like JDBC, JMS, Logging..etc


• It is recommended to keep your admin server running on an individual physical server (host) and configure rest of the managed server on the different physical  servers(s) or hosts.

What is Managed Server ?

• Managed servers are those which actually hosts your applications (JAR, WAR, EAR). In other words you deply your application on managed servers.


• As of now, Oracle has not commented on the maximum number of managed server a domain can have so, you can have as many as you need for your domain.

How the communication happens between Admin Server and Managed Server(s) ?

• The Administration Server stores the master copy of the domain configuration in a file called config.xml, including the configuration for all managed servers in the domain.


• Each Managed Server stores a local copy of its configuration.


• When a Managed Server starts, it connects to the Admin Server to synchronize the configuration.


• When configuration is changed, the Administration Server sends changed configuration to Managed Servers.

What is a cluster ?

• A cluster is a group of Managed Servers running simultaneously and working together to provide high availability, reliability/scalability and fail-over.


• All servers in a cluster must also be in the same domain.


• All servers within a cluster must be at the same Maintenance Pack Level.


• Clustered servers can be on the same or different
  machines.


• There can be multiple clusters in a domain.


• In the picture below the brown pentagons inside the purple ovals represent managed servers.

What is Node manager ?

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


• It must be configured and running on each physical server that hosts WebLogic Server instances which you want to control with Node Manager


• It is not associated with a domain and can start, stop, suspend, and restart any server instance that resides on the same physical server.


• Node manager is an optional entity but required to tart, stop, suspend, and restart servers using the Admin Console

NOTE: In the picture above the BLACK BOXES represents the individual Physical Servers OR Hosts.





What is Machine wrt Weblogic Domain ?

• A machine is a logical representation of the physical machine (computer) that hosts one or more WebLogic Server instances.


• If you run Node Manager on a machine that does not host an Administration Server, as is typical in production environments, you must create a machine configuration for each computer that runs a Node Manager process.


• The machine configuration includes information about the listen address and port number that the Administration Server uses to connect with the Node Manager process running on that machine.


• In a cluster, WebLogic Server uses machines to ensure that server session data is replicated on separate pieces of hardware.


• If the computer runs a UNIX operating system, you can create a UNIX machine configuration, which enables you to assign the process under which a WebLogic Server instance runs to a user ID (UID) or group ID (GID). The WebLogic Server process is assigned (bound) to the UID or GID after the computer has carried out all privileged startup actions.

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I think, Its a good time now to start with the weblogic domain configuration, what you say ???

Yeah,OK..Lets move on to the weblogic configuration wizard.....

STEPS for configuring a Weblogic domain would go as follows:

1.Below is the location where all your common scripts are located. So first traverse to that location:



2. config.sh is the script which helps you in creating and configuring a weblogic domain, so just invoke the configuration wizard by running the script, then select the radio button "Create a New Weblogic Domain" 

$config.sh



3. No change, just click on "Next", coz the default installer has already been selected.



4. Provide a name to your domain. and notice the domain location.



5. Enter credentials for the admin user "weblogic". The same user will be able to login to admin console and perform the administrative tasks.





6. A domain can be configured in either Development mode or in Production mode. Will discuss the difference in coming sessions.





7. Just select Admin Server and rest of the tasks can be performed from admin console.



8. Provide Admin Server name, hostname and the port number. Make sure the port is open.



9. Click on "Create" which will initiate the process of creating the domain.









10. Click on "Done" to complete the process.



11. Now, go to the prompt and check your domain directory and home.



12. execute the script startWeblogic.sh to start the Admin Server. Enter weblogic credentials when prompted.







13. Access the console. The URL will be if format:

http://<hostname>:<weblogic admin server port>/console





Thanks and Regards,

Diwakar Singh

Keep learning...Keep growing...