Jolokia is remote JMX with JSON over HTTP.

We use JMX a lot for low level, dynamic management of our systems. Even the most basic of MBean implementation that uses the "MBean" interface suffix and one concrete class implementation is far better than nothing. With our commitment to using JMX we have, over the years, developed a set of Java annotations and machinery to publish POJOs as MBeans.

We continue to use JConsole, over Java Visual VM, because of its utter simplicity. The tool does have some issues, but we know them well and they do not distract from the need to manage something quickly. The one area where this tool and other tools that I am aware of fall down is making the same change on several deployments.

For this we fall back to using the bash shell and Jolokia. Jolokia is remote JMX with JSON over HTTP. It is a servlet that is part of our standard Tomcat deployment. We have been using it for many years and it has not failed us yet. So, if I need to change some state on all our machines I run

for h in $HOST_DEPLOYMENTS
do
    curl "http://$h/jmx/write/object-name/attribute-name/new-value &
done

Where object name, etc are replaced as expected. (Curl is normally called with --silent and --fail command line options.)

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