Monday, June 30, 2014

Oracle Weblogic Basics

Understanding Key Oracle Fusion Middleware Concepts
Oracle Fusion Middleware provides two types of components:
  • Java component, which is an Oracle Fusion Middleware component that is deployed as one or more Java EE applications and a set of resources. Java components are deployed to an Oracle WebLogic Server domain as part of a domain template. Examples of Java components are the Oracle SOA Suite and Oracle WebCenter components.
  • system component, which is a manageable process that is not deployed as a Java application. Instead, a system component is managed by Oracle Process Manager and Notification (OPMN). System components are:
    • Oracle HTTP Server
    • Oracle Web Cache
    • Oracle Internet Directory
    • Oracle Virtual Directory
    • Oracle Forms Services
    • Oracle Reports
    • Oracle Business Intelligence Discoverer
    • Oracle Business Intelligence
A Java component and a system component are peers.
After you install and configure Oracle Fusion Middleware, your Oracle Fusion Middleware environment contains the following:
  • An Oracle WebLogic Server domain, which contains one Administration Server and one or more Managed Servers. The Administration Server contains Oracle WebLogic Server Administration Console and Oracle Enterprise Manager Fusion Middleware Control. The Managed Servers contain components, such as Oracle WebCenter and Oracle SOA Suite.
  • If your environment includes system components, one or more Oracle instances.
  • A metadata repository, if the components you installed require one. For example, Oracle SOA Suite requires a metadata repository. 
Below Figure shows an Oracle Fusion Middleware environment with an Oracle WebLogic Server domain that contains an Administration Server, two Managed Servers, and an Oracle instance. The environment also includes a metadata repository.
Figure 1-1 Oracle Fusion Middleware Environment
Description of Figure 1-1 follows

Your environment also includes a Middleware home, which consists of the Oracle WebLogic Server home, and optionally, an Oracle Common home and one or more Oracle homes.

1.3.1 What Is an Oracle WebLogic Server Domain?

An Oracle WebLogic Server administration domain is a logically related group of Java components. A domain includes 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 Java components, such as Web applications, EJBs, and Web services, and other resources, to the Managed Servers and use the Administration Server for configuration and management purposes only.
Managed Servers in a WebLogic Server domain can be grouped together into a cluster.
The directory structure of a domain is separate from the directory structure of the WebLogic Server home. It can reside anywhere; it need not be within the Middleware home directory. The top-level directory of a domain is referred to as the domain home.
An Oracle WebLogic Server domain is a peer of an Oracle instance. Both contain specific configurations outside of their Oracle homes.
Below figure shows an Oracle WebLogic Server domain with an Administration Server, three standalone Managed Servers, and three Managed Servers in a cluster.
Figure 1-2 Oracle WebLogic Server Domain
Description of Figure 1-2 follows

1.3.1.1 What Is the Administration Server?

The Administration Server operates as the central control entity for the configuration of the entire WebLogic Server domain. It maintains the domain's configuration documents and distributes changes in the configuration documents to Managed Servers. The Administration Server serves as a central location from which to manage and monitor all resources in a domain.
Each Oracle WebLogic Server domain must have one server instance that acts as the Administration Server.
To interact with the Administration Server, you can use the Oracle WebLogic Server Administration Console, Oracle WebLogic Scripting Tool (WLST), or create your own JMX client. In addition, you can use Fusion Middleware Control for some tasks.
Fusion Middleware Control and the WebLogic Administration Console run in the Administration Server. Fusion Middleware Control is a Web-based administration console used to manage Oracle Fusion Middleware, including components such as Oracle HTTP Server, Oracle SOA Suite, Oracle WebCenter, Oracle Portal, and Oracle Identity Management components. Oracle WebLogic Server Administration Console is the Web-based administration console used to manage the resources in an Oracle WebLogic Server domain, including the Administration Server and Managed Servers.

1.3.1.2 What Are 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, it connects to the domain's Administration Server to synchronize its configuration document with the document that the Administration Server maintains.
When you create a domain, you create it using a particular domain template. That template supports a particular component or group of components, such as Oracle SOA Suite. The Managed Servers in the domain are created specifically to host those particular Oracle Fusion Middleware components.
Oracle Fusion Middleware Java components (such as Oracle SOA Suite, Oracle WebCenter, and some Identity Management components), as well as customer-developed applications, are deployed to Managed Servers in the domain.
If you want to add other components, such as Oracle WebCenter, to a domain that was created using a template that supports another component, you can extend the domain by creating additional Managed Servers in the domain, using a domain template for the component which you want to add. See Section 9.2 for more information.
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. In a cluster, most resources and services are deployed identically to each Managed Server (as opposed to a single Managed Server), enabling failover and load balancing. A single domain can contain multiple WebLogic Server clusters, as well as multiple Managed Servers that are not configured as clusters. The key difference between clustered and non-clustered Managed Servers is support for failover and load balancing. These features are available only in a cluster of Managed Servers.

1.3.1.3 What Is Node Manager?

Node Manager is a Java utility that runs as a separate process from Oracle WebLogic Server and allows you to perform common operations for a Managed Server, regardless of its location with respect to its Administration Server. While use of Node Manager is optional, it provides valuable benefits if your Oracle WebLogic Server environment hosts applications with high-availability requirements.
If you run Node Manager on a computer that hosts Managed Servers, you can start and stop the Managed Servers remotely using the Administration Console or the command line. Node Manager can also automatically restart a Managed Server after an unexpected failure.

1.3.2 What Is an Oracle Instance?

An Oracle instance contains one or more system components, such as Oracle Web Cache, Oracle HTTP Server, or Oracle Internet Directory. The system components in an Oracle instance must reside on the same computer. An Oracle instance directory contains updatable files, such as configuration files, log files, and temporary files.
An Oracle instance is a peer of an Oracle WebLogic Server domain. Both contain specific configurations outside of their Oracle homes. However, unlike a domain, which can span multiple hosts, an Oracle instance must be located on a single host.
The directory structure of an Oracle instance is separate from the directory structure of the Oracle home. It can reside anywhere; it need not be within the Middleware home directory.

1.3.3 What Is a Middleware Home?

Middleware home consists of the Oracle WebLogic Server home, and, optionally, one Oracle Common home and one or more Oracle homes.
A Middleware home can reside on a local file system or on a remote shared disk that is accessible through NFS.

1.3.4 What Is a WebLogic Server Home?
WebLogic Server home contains installed files necessary to host a WebLogic Server. The WebLogic Server home directory is a peer of Oracle home directories and resides within the directory structure of the Middleware home.

1.3.5 What Is an Oracle Home and the Oracle Common Home?

An Oracle home contains installed files necessary to host a specific component or software suite. For example, the SOA Oracle home contains a directory that contains binary and library files for Oracle SOA Suite.
An Oracle home resides within the directory structure of the Middleware home. Each Oracle home can be associated with multiple Oracle instances or Oracle WebLogic Server domains. There can be multiple Oracle homes within each Middleware home.
The Oracle Common home contains the binary and library files required for Fusion Middleware Control and Java Required Files (JRF). There can be only one Oracle Common home within each Middleware home.

1.3.6 What Is the Oracle Metadata Repository?

The Oracle Metadata Repository contains metadata for Oracle Fusion Middleware components, such as Oracle BPEL Process Manager, Oracle B2B, and Oracle Portal. It can also contain metadata about the configuration of Oracle Fusion Middleware and metadata for your applications.
A metadata repository can be database-based or file-based. If it is database-based, you can create it in an existing database using the Repository Creation Utility (RCU).
Oracle Fusion Middleware supports multiple repository types. A repository type represents a specific schema or set of schemas that belong to a specific Oracle Fusion Middleware component (for example, Oracle SOA Suite or Oracle Internet Directory.)
A particular type of repository, the Oracle Metadata Services (MDS) repository, contains metadata for most Oracle Fusion Middleware components, such as Oracle B2B, and for certain types of applications.

1.4 Common Administration Tasks

As an administrator for Oracle Fusion Middleware, you can expect to be involved in the following tasks:
  • Installing Oracle Fusion Middleware software
  • Performing the initial configuration of the software
  • Configuring a metadata repository
  • Deploying applications
  • Managing administrative accounts
  • Monitoring the environment
  • Backing up and recovering your Oracle Fusion Middleware environment

1.5 Tools for Administering Oracle Fusion Middleware

The following are some of the tools and utilities that you can use in administering Oracle Fusion Middleware:
  • Oracle Enterprise Manager Fusion Middleware Control
    Fusion Middleware Control is a Web-based interface and is one of the primary tools for managing your Oracle Fusion Middleware environment. With it, you can check the status of the components, start and stop components, deploy Java EE applications, and perform other administrative tasks, such as creating clusters and managing log files. 
  • Oracle WebLogic Server Administration Console
    The Oracle WebLogic Server Administration Console is a Web browser-based, graphical user interface that you use to manage an Oracle WebLogic Server domain. 
  • WebLogic Scripting Tool (WLST)
    The WebLogic Scripting Tool (WLST) is a command-line scripting environment that you can use to create, manage, and monitor Oracle WebLogic Server domains.
  • Oracle Process Manager and Notification Server (OPMN)
    Oracle Process Manager and Notification Server (OPMN) manages and monitors a particular type of Oracle Fusion Middleware components, referred to as system components. 
  • Oracle Fusion Middleware Metadata Repository Creation Utility
    The Repository Creation Utility (RCU) creates a metadata repository in an existing database. You can use it to create a repository for overall configuration information and for configuration information for particular components. Not all Oracle Fusion Middleware components need a database-based metadata repository, but some, like the Oracle SOA Suite, do. 
  • System MBean browser
    An MBean is a Java object that represents a JMX manageable resource. Each manageable resource within the application server, such as an application or a resource adapter, is managed through an instance of the appropriate MBean. Each MBean exposes a management interface that is accessible through the System MBean Browser in Fusion Middleware Control. You can set MBean attributes, execute operations to call methods on an MBean, subscribe to notifications of errors or specific events, and display execution statistics.
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Here are few PPT slides from Web. A very basic introduction to Weblogic and it's troubleshooting.
Nice Post from the author...


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