Apache Tomcat Plug-in Overview and Prerequisites

1 Apache Tomcat Plug-in Overview and Prerequisites

This chapter provides an overview description of the Oracle system monitoring plug-in for Apache Tomcat and summarizes the prerequisites required before configuration.

The following topics are provided:

About Apache Tomcat

Apache Tomcat is an open source application server that implements the Java Servlet and Java Server Pages (JSP) specifications, providing an environment for Java code to run in. The Non-Oracle Middleware plug-in for Apache Tomcat extends Oracle Enterprise Manager Cloud Control 13c to add support for managing it.

By deploying the plug-in within your Cloud Control environment, you can use management features, such as availability and performance metrics, reports, and alerts.

Supported Versions

This plug-in supports the following versions of products:

Enterprise Manager Cloud Control 13c and higher (Oracle Management Service and Oracle Management Agent).
Apache Tomcat 8.x and later.
Apache Tomcat 7.x and earlier.

Apache Tomcat Plug-in Prerequisites

The following prerequisites must be met before you can deploy the plug-in:

Apache Tomcat is installed.
Remote JMX monitoring must be enabled when you start Apache Tomcat. You can enable JMX by adding -Dcom.sun.management.jmxremote.port to the following startup scripts:
- For UNIX and Linux: catalina.sh
- For Microsoft Windows: catalina.bat
For more information about remote monitoring and management, refer to the following link:
```
https://docs.oracle.com/javase/8/docs/technotes/guides/management/index.html
```
Enterprise Manager Cloud Control 13c Release 13.1.0.1.0 or higher (Oracle Management Service and Oracle Management Agent) is installed.

You can install the Management Agent on the same computer as Apache Tomcat (referred to as local Agent monitoring) or on a different computer (referred to as remote Agent monitoring). The way you configure the local or remote Management Agent is the same.

If you are using a remote Management Agent, then ensure that the Management Agent has access to the computer on which Apache Tomcat instance is running and the JMX port on which it is listening.
For monitoring an Apache Tomcat target, do not use a Management Agent that is already monitoring one of the following:
- Oracle WebLogic Managed Server
- IBM WebSphere Application Server
- JBoss Application Server
This is because different target types use different JMX versions, which could lead to metric collection errors for Apache Tomcat.

The following is an example of such a metric collection error for Apache Tomcat:
```
oracle.sysman.emSDK.emd.fetchlet.FetchletException:
oracle.sysman.emSDK.emd.fetchlet_FetchletException:
java.lang.SecurityException: sealing violation: package javax.management is sealed
```

Downloading the Apache Tomcat Plug-in

You can download plug-ins in online or offline mode. Online mode refers to an environment where you have Internet connectivity, and can download the plug-in directly through Enterprise Manager from My Oracle Support. Offline mode refers to an environment where you do not have Internet connectivity, or where the plug-in is not available from My Oracle Support.

See the Managing Plug-ins chapter in the Oracle Enterprise Manager Cloud Control Administrator's Guide for details on downloading the plug-in in either mode.

Deploying the Plug-in

You can deploy the plug-in to an Oracle Management Service instance using the Enterprise Manager Cloud Control console, or using the EM Command Line Interface (EMCLI). While the console enables you to deploy one plug-in at a time, the command line interface mode enables you to deploy multiple plug-ins at a time, thus saving plug-in deployment time and downtime, if applicable.

See the Managing Plug-ins chapter in the Oracle Enterprise Manager Cloud Control Administrator's Guide for instructions on deploying the plug-in:

Upgrading the Plug-in

The Self Update feature allows you to expand Enterprise Manager's capabilities by updating Enterprise Manager components whenever new or updated features become available. Updated plug-ins are made available via the Enterprise Manager Store, an external site that is periodically checked by Enterprise Manager Cloud Control to obtain information about updates ready for download. See the Updating Cloud Control chapter in the Oracle Enterprise Manager Cloud Control Administrator's Guide for steps to update the plug-in.

Undeploying the Plug-in

See the Managing Plug-ins chapter in the Oracle Enterprise Manager Cloud Control Administrator's Guide for steps to undeploy the plug-in.