Remote JMX connection

In my testing with Tomcat and Java 8, the JVM was opening an ephemeral port in addition to the one specified for JMX. The following code fixed me up; give it a try if you are having issues where your JMX client (e.g. VisualVM is not connecting.

-Dcom.sun.management.jmxremote.port=8989
-Dcom.sun.management.jmxremote.rmi.port=8989

Also see Why Java opens 3 ports when JMX is configured?


Had it been on Linux the problem would be that localhost is the loopback interface, you need to application to bind to your network interface.

You can use the netstat to confirm that it is not bound to the expected network interface.

You can make this work by invoking the program with the system parameter java.rmi.server.hostname="YOUR_IP", either as an environment variable or using

java -Djava.rmi.server.hostname=YOUR_IP YOUR_APP

I've spend more than a day trying to make JMX to work from outside localhost. It seems that SUN/Oracle failed to provide a good documentation on this.

Be sure that the following command returns you a real IP or HOSTNAME. If it does return something like 127.0.0.1, 127.0.1.1 or localhost it will not work and you will have to update /etc/hosts file.

hostname -i

Here is the command needed to enable JMX even from outside

-Dcom.sun.management.jmxremote 
-Dcom.sun.management.jmxremote.authenticate=false 
-Dcom.sun.management.jmxremote.ssl=false 
-Dcom.sun.management.jmxremote.port=1100
-Djava.rmi.server.hostname=myserver.example.com

Where as you assumed, myserver.example.com must match what hostname -i returns.

Obviously, you need to be sure that the firewall does not block you, but I'm almost sure that this is not your problem, the problem being the last parameter that is not documented.

Tags:

Java

Jmx

Jconsole