How to access JMX (Java Beans) from a process runn

Question

Why is it so hard to connect to a JMX port (using JConsole), when a process is run using Docker.

Of course I have exposed the JMX port to the host, and even used Sun specific options while running the Java process (following the instructions from http://ptmccarthy.github.io/2014/07/24/remote-jmx-with-docker/ ).

I am able to telnet to the host ip and the exposed JMX port, which tells that it is accessible. But I can't figure out a way to use JConsole and connect to the JMX service running in the container.

-Djava.rmi.server.hostname=$JMX_HOSTNAME
-Dcom.sun.management.jmxremote.port=$JMX_PORT
-Dcom.sun.management.jmxremote.rmi.port=$JMX_PORT

Answer 1

In the past, the two ports had to be different. Please try that for a start.

If thats not working:

Tomcat offers an additional component to set the second port mentioned, the JMX Remote Lifecycle Listener.

Please have a look at:

http://tomcat.apache.org/tomcat-7.0-doc/extras.html

http://tomcat.apache.org/download-70.cgi

I´m using this setting with catalina-jmx-remote.jar in my tomcat/lib directory to get through:

-Dcom.sun.management.jmxremote 
-Dcom.sun.management.jmxremote.ssl=false 
-Djava.rmi.server.hostname=localhost
-DrmiRegistryPortPlatform=10381 
-DrmiServerPortPlatform=10380

Plus these, but you wouldn´t need them in a dev environment.

-Dcom.sun.management.jmxremote.password.file=/home/tomcat/jmxremote.password 
-Dcom.sun.management.jmxremote.access.file=/home/tomcat/jmxremote.access 
-Dcom.sun.management.jmxremote.authenticate=true

Answer 2

What you currently have looks correct. To at least try and get it working, i'd try disabling auth & ssl. Then, once you get it working, think about re-enabling any security you require:

-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false

Answer 3

Indeed, you need those 2 ports to be different. One port is for the RMI registry and the other for the remoting protocol.

When specifying the URL to connect to the server from jconsole/visualvm use the port set in "-Dcom.sun.management.jmxremote.port" on the server side.