Configuring a WebLogic Server Environment

At the end of this chapter you will be able to:

• What is a Domain and Organizing the Domains
• Contents of a Domain and Domain Restrictions
• Configuring the Domain by using the Configuration Wizard
• Describe how the domain works and Domain Directory Structure

What Is a Domain?

A WebLogic Server administration domain is a logically related group of WebLogic Server resources. Domains include a special WebLogic Server instance called the Administration Server, which is the central point from which you configure and manage all resources in the domain. Usually, you configure a domain to include additional WebLogic Server instances called Managed Servers. You deploy Web applications, EJBs, Web Services, and other resources onto the Managed Servers and use the Administration Server for configuration and management purposes only.

 

Organizing Domains:

You can use a single WebLogic Server installation to create and run multiple domains, or you can use multiple installations to run a single domain. Depending on your particular business needs and system administration practices, you might decide to organize your domains based on criteria such as:

• Logical division of applications. For example, you might have one domain devoted to end-user functions such as shopping carts and another domain devoted to back-end accounting applications.

• Physical location. You might establish separate domains for different locations or branches of your business. Each physical location requires its own WebLogic Server installation.

• You might find that domains organized in small units can be managed more efficiently, perhaps by different system administrators. Contrarily, you might find that maintaining a single domain or a small number of domains makes it easier to maintain a consistent configuration.

For development or test environments, you can create a simple domain that consists of a single server instance. This single instance acts as an Administration Server and hosts the applications that you are developing. The wl_server domain that you can install with WebLogic Server is an example of this type of domain.  

Domain Overview

Contents of a Domain:

1) Administration Server:

The Administration Server operates as the central control entity for the configuration of the entire domain. It maintains the domain’s configuration documents and distributes changes in the configuration documents to Managed Servers. You can also use the Administration Server as a central location from which to monitor all resources in a domain. Admin Clients: To interact with the Administration Server, you can use the Administration Console, WLST, or create your own JMX client.  

2) Managed Servers and Managed Server Clusters:

Managed Servers host business applications, application components, Web Services, and their associated resources. To optimize performance, Managed Servers maintain a read-only copy of the domain's configuration document. When a Managed Server starts up, it connects to the domain's Administration Server to synchronize its configuration document with the document that the Administration Server maintains. For production environments that require increased application performance, throughput, or high availability, you can configure two or more Managed Servers to operate as a cluster. A cluster is a collection of multiple WebLogic Server instances running simultaneously and working together to provide increased scalability and reliability.  

3) Resources and Services

In addition to the Administration Server and Managed Servers, a domain also contains the resources and services that Managed Servers and deployed applications require.  

Managed Servers can use the following resources:

• Machine definitions that identify a particular, physical piece of hardware. A machine definition is used to associate a computer with the Managed Servers it hosts. This information is used by Node Manager in restarting a failed Managed Server, and by a clustered Managed Server in selecting the best location for storing replicated session data.

• Network channels that define default ports, protocols, and protocol settings that a Managed Server uses to communicate with clients. After creating a network channel, you can assign it to any number of Managed Servers and clusters in the domain.

• Virtual hosting, which defines a set of hostnames to which WebLogic Server instances (servers) or clusters respond. When you use virtual hosting, you use DNS to specify one or more hostnames that map to the IP address of a server or cluster. You also specify which Web applications are served by each virtual host.

Applications can use the following resources and services:

Security providers, which are modular components that handle specific aspects of security, such as authentication and authorization.

• Resource adapters, which are system libraries specific to Enterprise Information Systems (EIS), and provide connectivity to an EIS.

• Diagnostics and monitoring services.

• JDBC data sources, which enable applications to connect to databases.

• XML entity caches and registry of XML parsers and transformer factories.

• Messaging services such as JMS servers and store-and-forward services.

• Startup classes, which are Java programs that you create to provide custom, system-wide services for your applications.

• Work Managers, which determine how an application prioritizes the execution of its work based on rules you define and by monitoring actual run-time performance. You can create Work Managers for entire WebLogic Server domains or for specific application components.

• Work Contexts, which enable applications to pass properties to a remote context without including the properties in a remote call.

Note: All managed servers in a domain must run the same version of WebLogic Server. The administration server can run either the same version as the managed servers in the domain or a later service pack.  

Domain Restrictions:

In designing your domain configuration, note the following restrictions:

• Each domain requires its own Administration Server for performing management activities. When you use the Administration Console to perform management and monitoring tasks, you can switch back and forth between domains, but in doing so, you are connecting to different Administration Servers.

• All Managed Servers in a cluster must reside in the same domain; you cannot split a cluster over multiple domains.

• All Managed Servers in a domain must run the same version of the WebLogic Server software. The Administration Server may run either the same version as the Managed Servers in the domain or a later service pack.

• If you have created multiple domains, each domain must reference its own database schema. You cannot share a configured resource or subsystem between domains. For example, if you create a JDBC data source in one domain, you cannot use it with a Managed Server or cluster in another domain. Instead, you must create a similar data source in the second domain. Furthermore, two or more system resources cannot have the same name.

Common Domain Configurations

You might find it useful to configure multiple domains based on specific criteria, such as system administrator responsibilities, the logical classification of applications, the geographical locations of servers, or size. The following table outlines the most common domain configurations. 1) Domain with managed servers: In typical production environments, several managed servers can host applications, and an administration server performs management operations. 2) Domain with managed servers and clusters: In production environments that require increased performance, throughput, or availability for an application, several managed servers might be grouped in a cluster. In such a case, the domain consists of one or more clusters with the applications they host, additional managed servers, if necessary, and an administration server to perform management operations. 3) Stand-alone Server Domain: In development or test environments, a single application and server might be deployed independently without managed servers. In such a case, you can have a domain consisting of a single administration server that also hosts the applications you want to test or develop.   Note: In production environments, it is recommended that you deploy applications only on managed servers; the administration server should be reserved for management tasks.  

Overview of the Configuration Wizard:

Before you can develop and run a WebLogic application, you must first create a domain. The Configuration Wizard (illustrated in Figure 1-2), simplifies the process of creating and extending a domain. To create or extend a domain by using the Configuration Wizard, you simply select the product components to be included in the domain (or choose a template that best meets your requirements) and provide basic configuration information. The Configuration Wizard then creates or extends the domain by using the settings from templates.  

After you create a domain by using the Configuration Wizard, you can start a WebLogic Server instance to run in the domain for developing, testing, and deploying applications.  

Creating a Domain

You might want to customize your domain in the following circumstances:

• To create a multi-server or clustered domain when you are using the default settings. All the predefined templates delivered with the product create single-server domains.
• To use a database that is different from the default database in the domain or extension template. In this case, you need to customize the JDBC settings to point to the appropriate database.

• To customize the listen port and the SSL port

• To create a test environment using a domain template that you received, and to modify the domain configuration to work in the test environment based on your requirement.

 

Extending a Domain

• You can extend an existing domain by adding predefined applications and services, or additional product component functionality. For example, if you created a base WebLogic Server domain and want to add Workshop, you can extend the domain by using the Workshop extension.
• To extend a domain by using the Configuration Wizard, select the domain that you want to extend and then select the additional product component. Alternatively, you can extend an existing domain by specifying an extension template to include additional applications and services. You can also customize the JDBC connections and change the JMS file store. The Configuration Wizard uses your input to update the configuration files, such as config.xml, and all other generated components in the domain directory, as required.
• Figure 1-4 summarizes the steps for extending a domain by using the Configuration Wizard

.

 

Starting the Configuration Wizard:  

Starting in Graphical Mode          

You can start the Configuration Wizard in graphical mode from either the Windows Start menu or from the command line.           Note: If you attempt to start the Configuration Wizard in graphical mode on a system that cannot support graphical display, the Configuration Wizard automatically starts in console mode.

• To start the Configuration Wizard in graphical mode on a Windows platform, choose Start > Programs > Oracle WebLogic > WebLogic Server 10.3 > Tools > Configuration Wizard.

• To start the Configuration Wizard in graphical mode from a Windows command prompt or on a UNIX platform:

1. a) Open an MS-DOS command prompt window (on Windows) or a command shell (on UNIX).
2. b) Go to the commonbin subdirectory of the product installation directory and execute the following command:

On Windows: config.cmd            

On UNIX: sh config.sh  

Starting in Console Mode:

• When run in console mode, the Configuration Wizard is executed in a text-based environment. To start the Configuration Wizard in console mode:

1. Open an MS-DOS command prompt window (on Windows) or a command shell (on UNIX).

2. Go to the commonbin subdirectory of the product installation directory.

3. Execute the following command:

– Windows: config.cmd -mode=console            

– UNIX: sh config.sh -mode=console

Note: The command and arguments must be entered in lower case.

The Welcome screen is displayed.

• To proceed, respond to the prompts by entering the number associated with your choice, pressing Enter. The arrow (->) adjacent to a choice indicates the current selection.
• To accept the current selection, type next (or n) and press Enter.
• To close the Configuration Wizard, enter Exit (or x) and press Enter.
• To review or change earlier selections, enter Previous (or p) and press Enter.  

Note: silent mode is deprecated in WebLogic Server 9.X

Creating a WebLogic Domain

The Configuration Wizard guides you through the process of creating a new domain quickly and easily, by selecting the product components that you want to include in your domain, or by using domain templates.

1. Start the Configuration Wizard as described in Starting the Configuration Wizard. The Welcome window is displayed

2. Select create a new WebLogic domain and click Next.

3. Select Generate a domain configured automatically to support the following products: WebLogic Server is selected, by default. Select the checkboxes corresponding to the other products that you want to include in the

4) Click Next. The Configure Administrator Username and Password window are displayed and configure the username and password for the administrator:

5) Select the WebLogic domain startup mode:

• In the development mode, the configuration of security is relatively relaxed, allowing you to auto-deploy applications.
• In the production model, the configuration of security is stringent, requiring a user name and password to deploy applications. Before putting a domain into production, familiarize yourself with securing the production environment.

Select the JDK: In the JDK Selection pane, select the JDK for the startup mode that you selected in the WebLogic Domain Startup Mode pane. The Configuration Wizard presents a list of the JDKs included in the installer. You can choose one of these JDKs or another JDK that you have installed on your system.

Click next then The Customize Environment and Services Settings window is displayed.

6) Customizing the Environment and Service Settings… While creating the domain, you can specify the RDBMS security store settings, configure the distribution of your domain across servers, clusters, and machines, specify JDBC data sources, define JMS file store settings. Select Yes and click on Next.  

7) Configure the Administration Server and Managed Servers

8) Configure Clusters

9) Assign Servers to Clusters

10) Configure Machines

11) Assign Servers to Machines

12) Enter the name of the domain and specify the domain location.

13) Click Create.

Note: You cannot overwrite an existing domain. If a domain with the name you specified already exists in the selected location, you must either delete the existing domain or specify a different name or location for the new domain.  

Domain Directory Contents

1) domain-name

The name of this directory is the name of the domain.

2) autodeploy

This directory provides a quick way to deploy applications in a development server. When the WebLogic Server instance is running in development mode, it automatically deploys any applications or modules that you place in this directory. The files you place in this directory can be Java EE applications, such as: An EAR file, A WAR, EJB JAR, RAR archived module.

3) bin

This directory contains scripts that are used in the process of starting and stopping the Administration Server and the Managed Servers in the domain. These scripts are generally provided as .sh files for UNIX and .cmd files for Windows. The bin directory can optionally contain other scripts of domain-wide interest, such as scripts to start and stop database management systems, full-text search engine processes, etc.

4) config

This directory contains the current configuration and deployment state of the domain. The central domain configuration file, config.xml, resides in this directory.

5) console-ext:

This directory contains extensions to the Administration Console, which enable you to add content to the WebLogic Server Administration Console, replace content, and change the logos, styles, and colors without modifying the files that are installed with WebLogic Server. For example, you can add content that provides custom monitoring and management facilities for your applications.

6) init-info

This directory contains files used for WebLogic domain provisioning. You should not modify any files in this directory.

7) lib

Any JAR files you put in this directory are added to the system classpath of each server instance in the domain when the server’s Java virtual machine starts.

8) Pending

This directory contains domain configuration files representing configuration changes that have been requested, but not yet activated. Once the configuration changes have been activated, the configuration files are deleted from this directory.

9) Security:

This directory holds those security-related files that are the same for every WebLogic Server instance in the domain:  SerializedSystemIni.dat This directory also holds security-related files that are only needed by the domain’s Administration Server: DefaultAuthorizerInit.ldift, DefaultAuthenticatorInit.ldift, DefaultRoleMapperInit.ldift

10) Servers

This directory contains one subdirectory for each WebLogic Server instance in the domain. The subdirectories contain data that is specific to each server instance.

11) tmp

This directory stores temporary files used in the change management process. You should not modify any files in this directory.

12) User_staged_config:

By default, configuration information is automatically copied from the Administration Server to each Managed Server. If instead, you prefer to stage configuration changes manually, you can use this directory as an alternative to the config directory.  

Summary:

• What is a Domain and Organizing the Domains
• Contents of a Domain and Domain Restrictions
• Configuring the Domain by using the Configuration Wizard
• Describe how the domain works and Domain Directory Structure

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