9 Extending Enterprise Manager

About the Oracle Management Agent

In order to understand what it takes to develop a Management Plug-in, it is important to study the architecture of the Oracle Management Agent. Oracle Management Agents are deployed on each host, and are responsible for monitoring all components on that host. Out-of-box, the Management Agent knows how to monitor default target types, such as the Oracle Database. To monitor a particular target type, the Agent uses two XML files:

• Target Type Metadata File: specifies the metrics that should be monitored for this target type, and methods to retrieve those metrics.

• Target Type Default Collections File: specifies the default collection intervals and alert thresholds for each of the target metrics.

For each metric, the Management Agent retrieves the appropriate data using fetchlets, which are parameterized data access mechanisms that take arguments for input and return formatted data. The following table lists available fetchlets.

The Agent uses the information in the Target Type Default Collections file to determine, for each target, the metrics that need to be collected and the corresponding collection frequency. It then uses information in the Target Type Metadata Files to determine how to collect the data. Based on this information, the Agent uses the appropriate fetchlet to retrieve data from the monitored targets.

Designing your Management Plug-in

The design stage of the management plug-in creation process involves defining the monitoring parameters required to accurately monitor and manage your new component. This involves:

• Identifying performance and configuration metrics that should be collected.

• Determining how often each metric should be collected. Oracle recommends that the collection frequency for any metric should not be less than once every five minutes.

• Based on customer-specific operational practices, specifying default warning and/or critical thresholds on these metrics. Whenever a threshold is crossed, Enterprise Manager generates an alert, informing administrators of potential problems.

Developing Your Management Plug-in

Developing a plug-in based on the requirements identified in the design phase involves:

1. For each metric, determining the appropriate component-level API that exposes the metric.

2. Mapping a method used to retrieve a particular metric to a 'Fetchlet' provided with the Agent, writing appropriate scripts to retrieve metrics, and determining input parameters for fetchlets. For example, the OS fetchlet will require an OS script, and a URL Timing fetchlet will require a URL parameter.

3. Defining two XML files (Target Type definition file and Default Collections file) that the Agent will use to monitor the new target type. This involves declaring appropriate metrics, metric collection methods, collection frequencies, and metric thresholds in the specified XML format.

The example below is an excerpt from a target-type Metadata file showing a sample metric declaration for collecting CPU Utilization. The OS Command fetchlet is used to retrieve the metric value by running an existing Perl script.

<Metric NAME="Load" TYPE="TABLE"> 
   <TableDescriptor> 
       <ColumnDescriptor NAME="CPU Utilization" TYPE="NUMBER"/> 
   </TableDescriptor> 
   <QueryDescriptor FETCHLET_ID="OS"> 
<Property NAME="scriptsDir" SCOPE="SYSTEMGLOBAL"> scriptsDir     </Property> 
<Property NAME="script" SCOPE="GLOBAL"> %scriptsDir% /cpu_util.pl </Property>
</QueryDescriptor>
</Metric>

Once a metric has been defined in the Target Type Metadata file, the next step is to define metric collection frequency and appropriate metric thresholds. The following example includes a sample collections file for the MyDatabase target type, where CPU Utilization is collected every 10 minutes, and a critical alert should be generated when the metric value is greater than ("GT") ninety percent.

<TargetCollection TYPE="MyDatabase">
  <CollectionItem NAME="Load">
    <Schedule>
        <IntervalSchedule INTERVAL="10"/>
    </Schedule>
    <Condition column_name ="CPU Utilization" critical="90" operator="GT"/>
  </CollectionItem>
</TargetCollection>

Validating the Plug-in

Successful integration of new target types with the Enterprise Manager framework relies on accurate XML. It is essential that the Target Type Metadata file and Default Collections file are syntactically and structurally correct. It is also critical to simulate a runtime data collection for a new target type to ensure that proper data is collected, as well as ensuring that there are no adverse performance effects. To facilitate the validation process, Enterprise Manager provides a tool call ILINT.

Packaging the Plug-in

You package all of the files associated with a Management Plug-in (metadata files, monitoring scripts, report files) into a Management Plug-in Archive (MPA) via EM CLI. The MPA is a ".jar" file that contains one or more Management Plug-ins, thus facilitating easy import/export of plug-ins.

To run the EMCLI, open a terminal window on any machine where the EMCLI client is installed and execute the add_mp_to_mpa verb. The following example demonstrates verb usage:

emcli add_mp_to_mpa
       -mpa="/my_dir/my_new_type.jar"
       -mp_version="2.0"
       -ttd="/my_dir/ttd/new_type.xml"
       -dc="/my_dir/dc/new_type.xml"
       -file="MONITORING_SCRIPT:/my_dir/script1.pl"
       -file="MONITORING_SCRIPT:/my_dir/script2.pl"
       -func_desc="Management Plug-in to define target type new_type"

After you have added one or more Management Plug-ins to the archive file, you are ready to deploy your plug-in to Management Agents in your enterprise.

Deploying the Management Plug-in

After a Management Plug-in Archive file is created, Enterprise Manager makes it simple to deploy the new Management Plug-in. The deploy operation is performed directly from the Grid Control console and consists of three steps:

1. Import the Management Plug-ins into the Grid Control console.

   Figure 9-1 Management Plug-in Import Page

   
   Description of "Figure 9-1 Management Plug-in Import Page"
   
   

   Once imported, the plug-ins appear on the Management Plug-ins page, and can be deployed to any number of Management Agents simultaneously.

   Figure 9-2 Management Plug-ins Page

   
   Description of "Figure 9-2 Management Plug-ins Page"
   
   

2. Deploy the Management Plug-in(s) to the appropriate Agents.

   Management Plug-ins can be deployed simultaneously to any number of Agents without causing any downtime to production environments. Enterprise Manager automatically copies appropriate metadata files and monitoring scripts to the selected Agents.

   Figure 9-3 Deploy Management Plug-in Page

   
   Description of "Figure 9-3 Deploy Management Plug-in Page"
   
   

   Once the Management Plug-in is deployed, Management Agents can monitor targets of the new type.

3. Discover the Management Plug-ins at the Agent.

   Once a Management Plug-in is deployed, the Agent knows how to monitor the new target type. At this point, all that remains is to instruct the Agent to start monitoring one or more instances of the new target type. This involves discovering targets from the Agent home page by specifying a small set of target properties, such as SID and Username for a database.

Enhancing Default Target Home Pages with Real-Time Reports

Enterprise Manager provides a powerful reporting framework called Information Publisher, which allows you to:

• Create custom reports against the Management Repository via the Grid Control console or by using the Information Publisher PL/SQL API.

• Generate reports on a schedule and share them with the entire user community.

• Create out-of-box monitoring, configuration, and service-level reports.

When developing a Management Plug-in, you can enhance information available from a default target home page by developing a management report definition using the Information Publisher PL/SQL API. These report definitions can be packaged with the plug-in, and are available from the Reports tab on the default target home page.

Figure 9-5 Default Target Home Page with Real-Time Report

Description of "Figure 9-5 Default Target Home Page with Real-Time Report"