Configuring and Using the WebLogic Diagnostic Framework
The Diagnostic Image Capture component of the WebLogic Diagnostic Framework (WLDF) can be used to create a diagnostic snapshot, or dump, of a server's internal runtime state at the time of the capture. This information can be particularly useful for support personnel analyzing what might have contributed to a server failure.
The following topics tell how to configure and use the Diagnostic Image Capture component:
A diagnostic image capture can be initiated by:
The Diagnostic Image Capture component includes a first failure notification feature. When a server makes the transition into a failed state, this feature automatically triggers an image creation notification. That notification triggers the creation and capture of a diagnostic image. The first-failure notification feature ensures that the state of a server when it failed is preserved.
You can configure an image lockout period for first failure notifications. The image lockout time limits the number of diagnostic images that are captured in a specified time period. When a server fails and recovers multiple times in a short period of time—such as may happen due to storm-related power failures—the image-lockout period prevents the server from repeatedly capturing and persisting diagnostic images that are very similar in content and that unnecessarily use up system resources, such as disk space.
Because the diagnostic image capture is meant primarily as a post-failure analysis tool, there is little control over what information is captured. Available configuration options are:
Diagnostic Image Capture is configured in the config.xml file for a domain, under the <server>
element for the server, as shown in Listing 3-1:
Listing 3-1 Sample Diagnostic Image Capture Configuration
<domain>
<!-- Other domain configuration elements -->
<server>
<name>myserver</name>
<server-diagnostic-config>
<image-dir>logs\diagnostic_images</image-dir>
<image-timeout>2</image-timeout>
</server-diagnostic-config>
<!-- Other configuration details for this server -->
</server>
<!-- Other server configurations in this domain-->
</domain>
The most common sources of a server state are captured in a diagnostic image capture, including:
The Diagnostic Image Capture component captures and combines the images produced by the different server subsystems into a single server image file. In addition to capturing the most common sources of server state, this component captures images from all the server subsystems including, for example, images produced by the JMS, JDBC, EJB, and JNDI subsystems.
Note: A diagnostic image is a heavyweight artifact meant to serve as a server-level state dump for the purpose of diagnosing significant failures. It provides the capability to capture a significant amount of important data in a structured format and then to provide that data to support personnel for analysis.
An image is captured as a single file for the entire server. Each image has a unique name, as follows:
diagnostic_image_domain_server_yyyy_MM_dd_HH_mm_ss
The contents of the file include at least the following information: