JMX

1. JMX David Moran dmoran@nc.rr.com 10/20/03

2. Agenda • Overview • Managed Beans • Services • Remote API • J2EE Management • Implementations • Future Directions • Demo

3. Benefits • JMX is an API to for managing java applications. • Abstract the instrumentation for management information to a common interface to facilitate integrated management. • Distribute management by moving management functions to the agents. • Realtime deployment of services and updates. • Possible to use to manage any application or device (via JNI or SNMP etc..)

4. JMX Architecture Management Layer Agent Layer (MBeanServer) RMI Connector Agent Services Notifications Monitors/Timers MLET Java Client HTML Adapter Web Browser SNMP Adapter Instrumentation Layer SNMP Manager (HP OpenView) SNMP MBeans RMI Java Application Manageable Device Application Server

5. MBeanServer • The core of the agent. It provides a registry for MBeans. • Allows clients to discover and execute operations exposed by the MBeans • Makes available various services to facilitate management (I.e. monitoring, scheduling, etc) • Use “ObjectName” class to register objects with the MBeanServer

6. Instrument your resources as MBeans • MBean stands for “managed bean” • MBeans can represent a physical device or an application • You decide which attributes and methods you want to expose for management. • Use design patterns similar to JavaBeans • MBeans are exposed in an agent.

7. Standard MBeans • The simplest MBean • Provides a static representation of a manageable resource. • Implements a management interface of attributes and methods that a device or application exposes for management.

8. Notifications • Can be used to inform registered listeners with important events or state changes. • Similar to the java event model • Register once to all types of notifications • Can supply a filter to say which notifications it is interested in.

9. Dynamic MBeans • Useful if the management interface is not stable. • The management interface is defined at runtime. • Developer is responsible for checking the validity of the invocations.

10. DynamicMBean Interface <<Interface>> DynamicMBean getAttribute(String attribute) setAttribute(Attribute attribute) getAttributes (String[] attributes) setAttributes(AttibuteList attributes) getMBeanInfo() invoke(String actionName, Object[] params)

11. Model MBeans • Most flexible and thus most complicated MBeans • Extension of the dynamic MBean • Developers do not write an MBean class • The agent must supply the RequiredModelMBean and the Management Interface is defined outside of the Bean via setter methods. • Features include persistence, logging, and attribute caching.

12. Connectors/Adapters • A connector makes a Java Management Extensions (JMX) API MBean server accessible to remote Java technology-based clients. • Adapters are similar to connectors except they provide protocol translations (I.e. SNMP, HTML, etc.)

13. Agent Services • Mlet; (Management Applet) Dynamically adds class files to the server either locally or from a remote location. • Relation Service; Allows the definition of relationships between Mbeans • Monitors: Observe Mbean attributes and emit notifications when values change. • Timers: Emits user defined notifications at specific times.

14. JMX Remote API • Adds remote capability to the JMX spec • Makes the JMX agent accessible from outside the JVM. • Developed through the JCP JSR 160 • Standard support via RMI • Optional support via TCP Sockets (JMXMP) • API is as close as possible to the API defined by the JMX API. • Also support discovery/lookup services and defines security between the client and server. • As with RMI code must handle communication exceptions

15. J2EE Management • An MBean can get data directly from an EJB by invoking its access methods. • An MBean can receive data being pushed from an EJB. • Registers and Deletes an MBean with a JMX agent upon creation and destruction of an EJB

16. J2EE Management Spec JSR77 • This specification represents a model of the J2EE application server, and its subcomponents, that all J2EE-compliant application vendors are required to expose • Requires JMX • Part of J2EE 1.4 spec • Specifies the MEJB, which is a session bean, to expose the agent to remote clients.

17. Available JMX Implementations • Sun JMX 1.2.1 and Remote API 1.0 RI • JDMK value added product for purchase. • JBOSS JBOSS-MX • JMX Compliant Implementation available • MicroKernal Application architecture is based on JMX Agent technology. • NetManage • Various products for sale to help build and manage applications via JMX • MX4J • OpenSource Implemenation of JMX 1.1 • Currently working on 1.2 • Currently working on Remoting API

18. Future Directions • Use of metadata • Persistence • Reliable event handling • Master-agent/sub-agent functionality • Manageability for J2EE™ apps

19. DemoLogin Monitor Login Screen Management Console User Web Browser Talks to MBeanServer User Login (increases login counter) UserInfoMgr MBean UserInfo Entity Bean Jboss Application Server Jmx Agent Retrieve number of Logins Enable/Disable login permissions

20. Books • JMX in ActionBenjamin G. Sullins, Mark WhipplePublisher: Manning Publications Company • JMX: Managing J2EE with Java Management ExtensionsMarc Fleury, Juha Lindfors Publisher: Sams • Java and JMX: Building Manageable SystemsHeather Kreger, Ward K. Harold, Leigh Williamson, Ward HaroldPublisher: Pearson Education • Java Management ExtensionsJ. Steven Perry Publisher: O'Reilly & Associates, Incorporated • JMX ProgrammingMike JasnowskiPublisher: Wiley, John & Sons, Incorporated

21. References • Sun JMX Page: http://java.sun.com/products/JavaManagement • JMX Forum jmx-forum@java.sun.com • JBOSS MX: http://www.jboss.org/developers/projects/jboss/jbossmx.jsp • AdventNet: www.adventnet.com • http://www.gartner.com/reprints/adventnet/108841.html • Interview with Chris Ebro http://www.theserverside.com/events/library.jsp • JSR77 Aricle http://www.onjava.com/pub/a/onjava/2002/03/27/jsr77.html