Weblogic Server Domain You manage a WebLogic Server installation by creating WebLogic Server domains -- a logically related group of WebLogic Server resources managed as a unit. A domain includes one or more WebLogic Server instances and can also include WebLogic Server clusters. You deploy and manage your applications as part of a WebLogic Server domain. Config.xml The purpose of config.xml is to store changes to managed objects so that they are available when WebLogic Server is restarted. Each time you use the Administration Console or other WebLogic Server utilities to modify the config.xml file, WebLogic Server archives the older version. You can configure the number of archived files WebLogic Server keeps. Introduction to System Administration: You manage a WebLogic Server installation by using any of several system administration tools provided with WebLogic Server. A WebLogic Server installation can consist of a single WebLogic Server instance or multiple instances, each hosted on one or more physical machines. The system administration tools include the Administration Console, command line utilities, and an API, with which you manage security, database connections, messaging, transaction processing, and the runtime configuration of your applications. The tools also allow you to monitor the health of the WebLogic Server environment to ensure maximum availability and performance for your applications. System Administration Infrastructure System administration infrastructure in WebLogic Server is implemented using the Java Management Extension (JMX) specification from Sun Microsystems. The JMX API models system administration functions with Java objects called MBeans. Knowledge of this implementation as described in this discussion of system administration infrastructure is not necessary to manage a WebLogic Server domain. The Administration Server and Managed Servers One instance of WebLogic Server in each domain acts as an Administration Server. The Administration Server provides a central point for managing a WebLogic Server domain. All other WebLogic Server instances in a domain are called Managed Servers. In a domain with only a single WebLogic Server instance, that server functions both as Administration Server and Managed Server. For a typical production system, Oracle recommends that you deploy your applications only on Managed Servers. This practice allows you to dedicate the Administration Server to configuration and monitoring of the domain, while one or more Managed Servers service your applications. Administration Console The Administration Console is a Web Application hosted by the Administration Server. You access the Administration Console from any machine on the local network that can communicate with the Administration Server through a Web browser (including a browser running on the same machine as the Administration Server). The Administration Console allows you to manage a WebLogic Server domain containing multiple WebLogic Server instances, clusters, and applications. The management capabilities include: Configuration Stopping and starting servers Monitoring server health and performance Monitoring application performance Viewing server logs Assistants, which step you through the following tasks: Creating JDBC connection pools and DataSources Deploying your applications, Configuring SSL etc Through the Administration Console, System administrators can easily perform all WebLogic Server management tasks without having to learn the JMX API or the underlying management architecture. The Administration Server persists changes to attributes in the config.xml file for the domain you are managing. Starting the Administration Console This section contains instructions for starting the Administration Console. To start the Administration Console: 1. Start an Administration Server. 2. Open one of the supported Web browsers and open the following URL: http://hostname:port/console Where hostname is the DNS name or IP address of the Administration Server and port is the listen port on which the Administration Server is listening for requests (port 7001 by default). If you have configured a domain-wide Administration port, use that port number. If you configured the Administration Server to use Secure Socket Layer (SSL) you must add s after http as follows: https://hostname:port/console 3. When the login page appears, enter the user name and the password you used to start the Administration Server (you may have specified this user name and password during the installation process) or enter a user name that belongs to one of the following security groups: Administrators, Operators, Deployers, or Monitors. These groups provide various levels of access to system administration functions in the Administration Console. Using the security system, you can add or delete users to one of these groups to provide controlled access to the console. Elements of the Administration Console The Administration Console user interface includes the following panels. Change Center This is the starting point for using the Administration Console to make changes in WebLogic Server Change Center Domain Structure This panel contains a tree structure you can use to navigate to pages in the Administration Console. Select any of the nodes in the Domain Structure tree to view that page. Click a + (plus) icon in the Domain Structure to expand a node and a - (minus) icon to collapse the node. Domain Structure How do I... : This panel includes links to online help tasks that are relevant to the current Console page. System Status The System Status panel reports on the number of information, error, and warning messages that have been logged. Using the Change Center The starting point for using the Administration Console to make changes in your WebLogic Server domain is the Change Center. The Change Center provides a way to lock a domain configuration so you can make changes to the configuration while preventing other accounts from making changes during your edit session. The domain configuration locking feature is always enabled in production domains. It can be enabled or disabled in development domains. It is disabled by default when you create a new development domain. To change a production domain’s configuration, you must: 1. Locate the Change Center in the upper left of the Administration Console screen. 2. Click the Lock & Edit button to lock the configuration edit hierarchy for the domain. 3. Make the changes you desire on the relevant page of the Console. Click Save on each page where you make a change. 4. When you have finished making all the desired changes, click Activate Changes in the Change Center. As you make configuration changes using the Administration Console, you click Save (or in some cases Finish) on the appropriate pages. Undoing Changes You can revert any pending (saved, but not yet activated) changes by clicking Undo All Changes in the Change Center. Releasing the Configuration Lock You release the configuration lock as follows: Before you make changes, click Release Configuration in the Change Center to release the lock explicitly. After you save changes, click Activate Changes or Undo All Changes in the Change Center to release the lock implicitly. How Change Management Works To provide a secure, predictable means for distributing configuration changes in a domain, WebLogic Server imposes a change management process that loosely resembles a database transaction. The configuration of a domain is represented on the file system by a set of XML configuration files, centralized in the config.xml file, and at run time by a hierarchy of Configuration MBeans. When you edit the domain configuration, you edit a separate hierarchy of Configuration MBeans that resides on the Administration Server. To start the edit process, you obtain a lock on the edit hierarchy to prevent other people from making changes. When you finish making changes, you save the changes to the edit hierarchy. The changes do not take effect, however, until you activate them, distributing them to all server instances in the domain. When you activate changes, each server determines whether it can accept the change. If all servers are able to accept the change, they update their working configuration hierarchy and the change is completed. Dynamic and Non-Dynamic Changes Some changes you make in the Administration Console take place immediately when you activate them. Other changes require you to restart the server or module affected by the change. These latter changes are called non-dynamic changes. Non-dynamic changes are indicated in the Administration Console with this warning icon, . Changes to dynamic configuration attributes become available once they are activated, without restarting the affected server or system restart. These changes are made available to the server and run-time hierarchies once they are activated. Changes to non-dynamic configuration attributes require that the affected servers or system resources be restarted before they become effective. Note that WebLogic Server’s change management process applies to changes in domain and server configuration data, not to security or application data. Viewing Changes You can view any changes that you have saved, but not yet activated, by clicking the View Changes and Restarts link in the Change Center. The View Changes and Restarts link presents two tabs, Change List and Restart Checklist: The Change List tab presents all changes that have been saved, but not yet activated. The Restart Checklist lists all servers for which non-dynamic changes have been activated, but which require restarts before the changes become effective. Server Life Cycle At any time, a WebLogic Server instance is in a particular operating state. Commands—such as start, stop, and suspend—cause specific changes to the state of a server instance. The following sections describe WebLogic Server states, state transitions, life cycle commands. Life Cycle Overview The series of states through which a WebLogic Server instance can transition is called the server life cycle. Figure illustrates the server life cycle and the relationships between WebLogic Server operating states. Understanding WebLogic Server States WbLogic Server displays and stores information about the current state of a server instance: SHUTDOWN: In the SHUTDOWN state, a server instance is configured but inactive. A server instance reaches the SHUTDOWN state as a result of a graceful shutdown or forced shutdown. STARTING: During the STARTING state, a WebLogic Server instance transitions from SHUTDOWN to STANDBY, as a result of a Start, Start in Admin, or Start in Standby command. In the STARTING state, a server instance cannot accept any client or administrative requests. The server instance obtains its configuration data: An Administration Server retrieves domain configuration data, including the domain security configuration, from its config directory. A Managed Server contacts the Administration Server for its configuration and security data. If the Managed Server is configured for SSL communications, it uses its own certificate files, key files, and other SSL- related files and contacts the Administration Server for the remaining configuration and security data. STANDBY: A server instance in STANDBY does not process any request—its regular Listen Port is closed. The Administration Port is open, and accepts life cycle commands that transition the server instance to either the RUNNING or the SHUTDOWN state. Other Administration requests are not accepted. Starting a server instance in standby is a method of keeping it available as a “hot” backup, a useful capability in high-availability environments. The only life cycle command that causes a server instance to enter the STANDBY state and remain in that state is the Start in Standby command. A server instance transitions through the STANDBY state when you issue a Start or a Start in Admin command. A server in the STANDBY state does not accept requests from external clients. ADMIN: In the ADMIN state, WebLogic Server is up and running, but available only for administration operations, allowing you to perform server and application-level administration tasks. When a server instance is in the ADMIN state: The Administration Console is available. The server instance accepts requests from users with the admin role. Requests from non-admin users are refused. Applications are activated in the application ADMIN state. They accept requests from users with the admin and AppTester roles. Users with these roles, accessing an application in the application ADMIN state, have access to all application functionality, not just administrative functions. The JDBC, JMS, and JTA subsystems are active, and administrative operations can be performed upon them. However, you do not have to have administrator-level privileges to access these subsystems when the server is in the ADMIN state. Deployments or re-deployments are allowed, and take effect when you transition the server instance from the ADMIN to the RUNNING state (using the Resume command). ClusterService is active and listens for heartbeats and announcements from other cluster members. It can detect that other Managed Servers have joined the cluster, but is invisible to other cluster members. You can transition a server instance to the ADMIN state using the Start in Admin, Suspend, or Force Suspend commands. A server instance transitions through the ADMIN state as a result of Start, Shutdown, and Force Shutdown commands. You can transition a server instance in the ADMIN state to RUNNING with the Resume command, or to SHUTDOWN, with the Shutdown or Force Shutdown command. RESUMING: During this transitional state, WebLogic Server performs the operations required to move itself from the STANDBY or ADMIN state to the RUNNING state. A server instance transitions to the RESUMING state when you issue the Resume command. A server instance transitions through the RESUMING state when you issue the Start command. RUNNING: In the RUNNING state, WebLogic Server is fully functional, offers its services to clients, and can operate as a full member of a cluster. A server instance transitions to the RUNNING state as a result of the Start command, or the Resume command from the ADMIN or STANDBY states. You can transition a server instance in the RUNNING state to the SUSPENDING state or the FORCE_SUSPENDING state using graceful and force Suspend and Shutdown commands. SUSPENDING: During this transitional state, WebLogic Server performs the operations required to place itself in the ADMIN state, suspending a subset of WebLogic Server subsystems and services in an ordered fashion, and completing a predefined portion of the application work currently in process (“in-flight” work). A server instance transitions to the SUSPENDING state when you issue the Suspend command. A server instance transitions through the SUSPENDING state when you issue a Shutdown command. FORCE_SUSPENDING: During this transitional state, WebLogic Server performs the operations required to place itself in the ADMIN state, suspending a subset of WebLogic Server subsystems and services in an ordered fashion. During the FORCE_SUSPENDING state, WebLogic Server does not complete in-flight work gracefully; application work in progress is abandoned. A server instance transitions through the FORCE_SUSPENDING state when you issue the Force Suspend or Force Shutdown command. SHUTTING_DOWN : During this transitional state, WebLogic Server completes the suspension of subsystems and services and does not accept application or administration requests. A server instance transitions to the SHUTTING_DOWN state when you issue a Shutdown or Force Shutdown command. FAILED: A running server instance can fail as a result of out-of-memory exceptions or stuck application threads, or if one or more critical services become dysfunctional. A server instance monitors its health, and upon detecting that one or more critical subsystems are unstable, it declares itself FAILED. A FAILED server instance cannot satisfy administrative or client requests. When a server instance enters the FAILED state, it attempts to return to a non- failed state. If it failed prior to reaching the ADMIN state, the server instance shuts itself down with an exit code that is less than zero. If the server instance fails after reaching the ADMIN state, but before reaching the RUNNING state, by default, it returns to the ADMIN state, if the administration port is enabled. Lifecycle commands: Start: When a server instance starts, it: Retrieves its configuration data. An Administration Server retrieves domain configuration data, including security configuration data, from the config.xml for the domain. A Managed Server contacts the Administration Server for its configuration and security data. Starts its kernel-level services, which include logging and timer services. Initializes subsystem-level services with the configuration data that it retrieved in step 1. These services include the following: Security Service JCA Container RMI Service JDBC Container Cluster Service EJB Container IIOP Service Web Container Naming Service Deployment Manager RMI Naming Service JMS Provider File Service Remote Management Transaction Service Deploys modules (applications, ex: .war, .ear files) in the appropriate container and in the order that you specify in the WebLogic Server Administration Console. Graceful Shutdown A graceful shutdown gives WebLogic Server subsystems time to complete certain application processing currently in progress. The work that it completes during graceful shutdown is referred to as in-flight work. During a graceful shutdown, subsystems complete in-flight work and suspend themselves in a specific sequence and in a synchronized fashion, so that back-end subsystems like JDBC connection pools are available when front-end subsystems are suspending themselves. Forced Shutdown A forced shutdown is immediate—WebLogic Server subsystems suspend all application processing currently in progress.
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