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Understanding Oracle WebLogic Server
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13 Monitoring, Diagnosing, and Troubleshooting

This chapter describes monitoring, diagnosing, and troubleshooting in WebLogic Server.

This chapter includes the following sections:

WebLogic Server Diagnostics Framework

The WebLogic Diagnostics Framework (WLDF) is a monitoring and diagnostic framework that defines and implements a set of services that run within WebLogic Server processes and participate in the standard server life cycle. Using WLDF, you can create, collect, analyze, archive, and access diagnostic data generated by a running server and the applications deployed within its containers. This data provides insight into the run-time performance of servers and applications and enables you to isolate and diagnose faults when they occur.

WLDF includes several components for collecting and analyzing data:

  • Integration with JavaHotSpot—If WebLogic Server is configured with Java HotSpot VM, WebLogic Server events can optionally be propagated to the Java Flight Recorder, a performance monitoring and profiling tool. WebLogic Server provides specific integration points with Java Flight Recorder:

    • WebLogic Server events are propagated to Java Flight Recorder for inclusion in a common data set for runtime or post-incident analysis.

    • The flight recording data is also included in WLDF diagnostic image captures, enabling you to capture flight recording snapshots based on WLDF watch rules. This full set of functionality enables you to capture and analyze runtime system information for both the JVM and the Fusion Middleware components running on it, in a single view

  • Diagnostic Image Capture—Creates a diagnostic snapshot from the server that can be used for post-failure analysis. The diagnostic image capture includes Java Flight Recorder data, if it is available, that can be viewed in Java Mission Control.

  • Built-in Diagnostic Modules—Provide a simple and easy-to-use mechanism for performing basic health and performance monitoring of a WebLogic Server instance. The built-in diagnostic modules collect data from key WebLogic Server run-time MBeans that monitor the main components of a server instance, such as the WebLogic Server run-time, JDBC, JMS, and Java EE containers hosting servlets and EJBs.

  • Archive—Captures and persists data events, log records, and metrics from server instances and applications.

  • Instrumentation—Adds diagnostic code to WebLogic Server instances and the applications running on them to execute diagnostic actions at specified locations in the code. The Instrumentation component provides the means for associating a diagnostic context with requests so they can be tracked as they flow through the system. The WebLogic Server Administration Console includes a Request Performance page, which shows real-time and historical views of method performance information that has been captured through the WLDF instrumentation capabilities, serving as a tool that can help identify performance problems in applications.

  • Harvester—Captures metrics from run-time MBeans, including WebLogic Server MBeans and custom MBeans, which can be archived and later accessed for viewing historical data.

  • Watches and Notifications—Provides the means for monitoring server and application states and sending notifications based on criteria set in the watches.

  • Monitoring Dashboard—The Monitoring Dashboard provides views and tools for graphically presenting diagnostic data about servers and applications running on them. The underlying functionality for generating, retrieving, and persisting diagnostic data is provided by the WebLogic Diagnostics Framework. The Monitoring Dashboard provides additional tools for presenting that data in charts and graphs.

    The diagnostic data displayed by the Monitoring Dashboard consists of runtime MBean attributes with numeric or Boolean values that are useful to measure, either as their current values or as their changes over time. These values, referred to in the Monitoring Dashboard as metrics, originate from one or more runtime MBean instances from one or more servers in the domain.

WLDF provides a set of standardized application programming interfaces (APIs) that enable dynamic access and control of diagnostic data, as well as improved monitoring that provides visibility into the server. Independent Software Vendors (ISVs) can use these APIs to develop custom monitoring and diagnostic tools for integration with WLDF.

WLDF enables dynamic access to server data through standard interfaces, and the volume of data accessed at any given time can be modified without shutting down and restarting the server.

Logging Services

WebLogic logging services provide facilities for writing, viewing, filtering, and listening for log messages. These log messages are generated by WebLogic Server instances, subsystems, and Java EE applications that run on WebLogic Server or in client JVMs. WebLogic Server subsystems use logging services to provide information about events such as the deployment of new applications or the failure of one or more subsystems. A server instance uses them to communicate its status and respond to specific events. For example, you can use WebLogic logging services to report error conditions or listen for log messages from a specific subsystem.

By default, WebLogic logging services use an implementation based on the Java Logging APIs. However, you can reconfigure WebLogic logging services to use Log4j instead. In addition, WebLogic Server also provides the Server Logging Bridge, which provides a lightweight mechanism for applications that currently use Java Logging or Log4J Logging to have their log messages redirected to WebLogic logging services. Applications can use the Server Logging Bridge with their existing configuration; no code changes or programmatic use of the WebLogic Logging APIs is required.

SNMP Support

With SNMP, a manager sends a request for information about managed resources to an agent. The agent gathers the requested data and returns a response. You can also configure agents to issue unsolicited reports (notifications) to managers when they detect predefined thresholds or conditions on a managed resource.

To request data about a specific managed resource, a manager must be able to uniquely identify the resource. In SNMP, each type of managed resource is described in a Management Information Base (MIB) as a managed object with a unique object identifier (OID). Individual organizations define their specific managed objects in MIB modules. Both manager and agent must have access to the same MIB module to communicate about specific managed resources.

Custom JMX Applications

To integrate custom management systems with the WebLogic Server management system, WebLogic Server provides standards-based interfaces that are fully compliant with the Java Management Extensions (JMX) specification. Software vendors can use these interfaces to monitor WebLogic Server MBeans, to change the configuration of a WebLogic Server domain, and to monitor the distribution (activation) of those changes to all server instances in the domain. While JMX clients can perform all WebLogic Server management functions without using Oracle's proprietary classes, Oracle recommends that remote JMX clients use WebLogic Server protocols (such as T3) to connect to WebLogic Server instances.

Java EE Management APIs

The Java EE Management specification describes a standard data model for monitoring and managing the run-time state of any Java EE Web application server and its resources. It includes standard mappings of the model through a Java EE Management EJB Component (MEJB).

The Java EE Management APIs enable a software developer to create a single Java program that can discover and browse resources, such as JDBC connection pools and deployed applications, on any Java EE Web application server. The APIs are part of the Java EE Management Specification, which requires all Java EE Web application servers to describe their resources in a standard data model.

Roadmap for Monitoring, Diagnosing, and Troubleshooting in WebLogic Server

Table 13-1 Roadmap for Monitoring, Diagnosing, and Troubleshooting in WebLogic Server

Major Task Subtasks and Additional Information

Learning more about WLDF components

Learning more about WebLogic logging services

Using the Monitoring Dashboard

Using SNMP with WebLogic Server

Creating JMX applications to manage WebLogic Server

Learning more about the Java EE Management APIs