Has anyone ever got a remote JMX JConsole to work?

Question

It seems that I've never got this to work in the past. Currently, I KNOW it doesn't work.

But we start up our Java process:

-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=6002
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false

I can telnet to the port, and "something is there" (that is, if I don't start the process, nothing answers, but if I do, it does), but I can not get JConsole to work filling in the IP and port.

Seems like it should be so simple, but no errors, no noise, no nothing. Just doesn't work.

Anyone know the hot tip for this?

Answer 1

Are you running on Linux? Perhaps the management agent is binding to localhost:

http://java.sun.com/j2se/1.5.0/docs/guide/management/faq.html#linux1

Answer 2

When testing/debugging/diagnosing remote JMX problems, first always try to connect on the same host that contains the MBeanServer (i.e. localhost), to rule out network and other non-JMX specific problems.

Answer 3

You are probably experiencing an issue with a firewall. The 'problem' is that the port you specify is not the only port used, it uses 1 or maybe even 2 more ports for RMI, and those are probably blocked by a firewall.

One of the extra ports will not be know up front if you use the default RMI configuration, so you have to open up a big range of ports - which might not amuse the server administrator.

There is a solution that does not require opening up a lot of ports however, I've gotten it to work using the combined source snippets and tips from

http://forums.sun.com/thread.jspa?threadID=5267091

http://blogs.sun.com/jmxetc/entry/connecting_through_firewall_using_jmx

http://java.sun.com/javase/6/docs/technotes/guides/management/agent.html

It's even possible to setup an ssh tunnel and still get it to work :-)

Answer 4

Adding '-Djava.rmi.server.hostname=<host ip>' resoleved this problem for me.

Answer 5

This fixed my issues on a box with external/internal IP addresses great - JMX works like a charm.

Answer 6

I am running JConsole/JVisualVm on windows hooking to tomcat running Linux Redhat ES3.

Disabling packet filtering using the following command did the trick for me:

/usr/sbin/iptables -I INPUT -s jconsole-host -p tcp --destination-port jmxremote-port -j ACCEPT

where jconsole-host is either the hostname or the host address on which JConsole runs on and jmxremote-port is the port number set for com.sun.management.jmxremote.port for remote management.