Jolokia is a fresh way to access JMX MBeans remotely. It is different from JSR-160 connectors in that it is an agent-based approach which uses JSON over HTTP for its communication in a REST-stylish way.

Multiple agents are provided for different environments:

• WAR Agent for deployment as web application in a JEE Server.
• OSGi Agent for deployment in an OSGi container. This agent is packaged as a bundle and comes in two flavors (minimal, all-in-one).
• Mule Agent for usage within a Mule ESB
• JVM JDK6 Agent which can be used with any Oracle/Sun JVM, Version 6 and which is able to attach to a running Java process dynamically.

Features

The agent approach as several advantages:

• Firewall friendly

  Since all communication is over HTTP, proxying through firewalls becomes mostly a none-issue (in contrast to RMI communication, which is the default mode for JSR-160)

• Polyglot

  No Java installation is required on the client side. E.g. Jmx4Perl provides a rich Perl client library and Perl based tools for accessing the agents.

• Simple Setup

  The Setup is done by a simple agent deployment. In contrast, exporting JMX via JSR-160 can be remarkable complicated (see these blog posts for setting up Weblogic and JBoss for native remote JMX exposure setup)

Additionally, the agents provide extra features not available with JSR-160 connectors:

• Bulk requests

  In contrast to JSR-160 remoting, Jolokia can process many JMX requests with a single round trip. A single HTTP POST request puts those requests in its JSON payload which gets dispatched on the agent side. These bulk requests can increase performance drastically, especially for monitoring solutions. The Nagios plugin check_jmx4perl uses bulk requests for its multi-check feature.

• Fine grained security

  In addition to standard HTTP security (SSL, HTTP-Authentication) Jolokia supports a custom policy with fine grained restrictions based on multiple properties like the client's IP address or subnet, and the MBean names, attributes, and operations. The policy is defined in an XML format with support for allow/deny sections and wildcards.

• Proxy mode

  Jolokia can operate in an agentless mode where the only requirement on the target platform is the standard JSR-160 export of its MBeanServer. A proxy listens on the front side for Jolokia requests via JSON/HTTP and propagates these to the target server through remote JSR-160 JMX calls. Bulk requests get dispatched into multiple JSR-160 requests on the proxy transparently.

Resources

• The Jolokia Forum can be used for questions about Jolokia (and Jmx4perl).

• For bug reports, please use the Github Issue tracker.

• Most of the time, I'm hanging around at Freenode in #jolokia, too.

Even more information on Jolokia can be found at www.jolokia.org, including a complete reference manual.