Table of Contents
The Java Management Extensions (JMX) API is a standard API for managing and monitoring resources such as applications, devices, services, and the Java virtual machine.
Typical uses of the JMX technology include:
Consulting and changing application configuration.
Accumulating and making available statistics about application behavior.
Notifying of state changes and erroneous conditions.
The JMX API includes remote access, so a remote management program can interact with a running application for these purposes.
Jetty JMX integration uses the platform MBean server implementation that Java VM provides. The integration is based on the ObjectMBean implementation of DynamicMBean. This implementation allows you to wrap an arbitrary POJO in an MBean and for [http://dev.eclipse.org/viewcvs/index.cgi/jetty/trunk/jetty-jmx/src/main/resources/org/eclipse/jetty/?root=RT_Jetty properties files]. to provide metadata.
TheMBeanContainer immplementation of the Container.Listener inteface coordinates creation of MBeans. The Jetty Server and it's components use a [http://download.eclipse.org/jetty/stable-7/apidocs/org/eclipse/jetty/util/component/Container.html Container] to maintain a containment tree of components and to support notification of changes to that tree. The MBeanContainer class listens for Container events and creates and destroys MBeans as required to wrap all Jetty components.
You can access the MBeans that Jetty publishes both through built-in Java VM connector via JConsole, or by registering a remote JMX connector and using a remote JMX agent to monitor Jetty.
This guide describes how to initialize and configure the Jetty JMX integration.
To monitor an application using JMX, perform the following steps:
Configure the application to instantiate an MBean container.
Instrument objects to be MBeans.
Provide access for JMX agents to MBeans.
The simplest way to access the MBeans that Jetty publishes is to use the JConsole utility the Java Virtual Machine supplies. See [[Jetty/Howto/Run Jetty_with_JConsole|Run Jetty with JConsole]] for instructions on how to configure JVM for use with JConsole.
To access Jetty MBeans via JConsole, you must:
Enable the registration of Jetty MBeans into the platform MBeanServer.
Enable a JMXConnectorServer so that JConsole can connect and visualize the MBeans.
Configuring Jetty JMX integration differs for standalone and embedded Jetty.
When running in standalone mode, you can use the jetty-jmx.xml
configuration file to
configure the MBeanContainer instance for a Jetty server. You can run this with the standard configuration file
as follows:
java -jar start.jar OPTIONS=Server,jmx etc/jetty-jmx.xml etc/jetty.xml
Make sure that the jetty-jmx.xml
is the first XML file listed
in the command line to ensure that Jetty properly detects all instances of objects that should be registered as
MBeans.
When running Jetty embedded into an application, create and configure an MBeanContainer instance as follows:
Server _server = new Server(); // Setup JMX MBeanContainer mbContainer=new MBeanContainer(ManagementFactory.getPlatformMBeanServer()); _server.getContainer().addEventListener(mbContainer); _server.addBean(mbContainer); // Register loggers as MBeans mbContainer.addBean(Log.getLog());
Notice that Jetty creates the MBeanContainer immediately after creating the Server, and immediately after registering it as an EventListener of the Server's Container object.
Because logging is initialized prior to the MBeanContainer, it is necessary to register the logger
manually via MBeanContainer.addBean().
If you are using the ??? you should copy the
etc/jetty-jmx.xml
file into your webapp project somewhere, such as src/etc,
then
add a <jettyconfig> element to the plugin <configuration>:
<plugin> <groupid>org.mortbay.jetty</groupid> <artifactid>maven-jetty-plugin</artifactid> <version>9.0.0.M2</version> <configuration> <scanintervalseconds>10</scanintervalseconds> <jettyXml>src/etc/jetty-jmx.xml</jettyXml> </configuration> </plugin>
There are two ways of enabling remote connectivity so that JConsole can connect to visualize MBeans.
Use the com.sun.management.jmxremote
system property on the command line. Unfortunately,
this solution does not play well with firewalls and it is not flexible.
Use Jetty's ConnectorServer
class. To enable use of this class, uncomment the
correspondent portion in etc/jetty-jmx.xml,
like this:
<New id="ConnectorServer" class="org.eclipse.jetty.jmx.ConnectorServer"> <Arg> <New class="javax.management.remote.JMXServiceURL"> <Arg type="java.lang.String">rmi</Arg> <Arg type="java.lang.String" /> <Arg type="java.lang.Integer"><SystemProperty name="jetty.jmxrmiport" default="1099"/></Arg> <Arg type="java.lang.String">/jndi/rmi://<SystemProperty name="jetty.jmxrmihost" default="localhost"/>:<SystemProperty name="jetty.jmxrmiport" default="1099"/>/jmxrmi</Arg> </New> </Arg> <Arg>org.eclipse.jetty.jmx:name=rmiconnectorserver</Arg> <Call name="start" /> </New>
This configuration snippet starts an RMIRegistry and a JMXConnectorServer both on port 1099 (by default), so that firewalls should open just that one port to allow connections from JConsole.
JMXConnectorServer several options to restrict access. For a complete guide to controlling authentication and authorization in JMX, see Authentication and Authorization in JMX RMI connectors in Luis-Miguel Alventosa's blog.
To restrict access to the JMXConnectorServer, you can use this configuration, where the
jmx.password
and jmx.access
files have the format specified in the blog entry
above:
<New id="ConnectorServer" class="org.eclipse.jetty.jmx.ConnectorServer"> <Arg> <New class="javax.management.remote.JMXServiceURL"> <Arg type="java.lang.String">rmi</Arg> <Arg type="java.lang.String" /> <Arg type="java.lang.Integer"><SystemProperty name="jetty.jmxrmiport" default="1099"/></Arg> <Arg type="java.lang.String">/jndi/rmi://<SystemProperty name="jetty.jmxrmihost" default="localhost"/>:<SystemProperty name="jetty.jmxrmiport" default="1099"/>/jmxrmi</Arg> </New> </Arg> <Arg> <Map> <Entry> <Item>jmx.remote.x.password.file</Item> <Item> <New class="java.lang.String"><Arg><Property name="jetty.home" default="." />/resources/jmx.password</Arg></New> </Item> </Entry> <Entry> <Item>jmx.remote.x.access.file</Item> <Item> <New class="java.lang.String"><Arg><Property name="jetty.home" default="." />/resources/jmx.access</Arg></New> </Item> </Entry> </Map> </Arg> <Arg>org.eclipse.jetty.jmx:name=rmiconnectorserver</Arg> <Call name="start" /> </New>
Using the JMX API, you can also write a custom application to monitor your Jetty server. To allow this
application to connect to your Jetty server, you need to uncomment the last section of your
etc/jetty-jmx.xml
configuration file and optionally modify the endpoint name. Doing so creates a JMX
HTTP connector and registers a JMX URL that outputs to the Stderr
log.
You should provide the URL that appears in the log to your monitor application in order to create an
MBeanServerConnection.
You can use the same URL to connect to your Jetty instance from a remote machine
using JConsole. See the configuration
file for more details.