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

The following worked for me (though I think port 2101 did not really contribute to this):

-Dcom.sun.management.jmxremote.port=2100
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.local.only=false
-Dcom.sun.management.jmxremote.rmi.port=2101
-Djava.rmi.server.hostname=<IP_ADDRESS>OR<HOSTNAME>

I am connecting from a remote machine to a server which has Docker running and the process is inside the container. Also, I stopped firewallD but I don't think that was the issue as I could telnet to 2100 even with the firewall open. Hope it helps.

Answer 2

Getting JMX through the Firewall is really hard. The Problem is that standard RMI uses a second random assigned port (beside the RMI registry).

We have three solution that work, but every case needs a different one:

1. JMX over SSH Tunnel with Socks proxy, uses standard RMI with SSH magic http://simplygenius.com/2010/08/jconsole-via-socks-ssh-tunnel.html

2. JMX MP (alternative to standard RMI), uses only one fixed port, but needs a special jar on server and client http://meteatamel.wordpress.com/2012/02/13/jmx-rmi-vs-jmxmp/

3. Start JMX Server form code, there it is possible to use standard RMI and use a fixed second port: https://issues.apache.org/bugzilla/show_bug.cgi?id=39055

Answer 3

I'm using boot2docker to run docker containers with Tomcat inside and I've got the same problem, the solution was to:

• Add -Djava.rmi.server.hostname=192.168.59.103
• Use the same JMX port in host and docker container, for instance: docker run ... -p 9999:9999 .... Using different ports does not work.

Answer 4

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

Answer 5

I have a solution for this:

If your Java process is running on Linux behind a firewall and you want to start JConsole / Java VisualVM / Java Mission Control on Windows on your local machine to connect it to the JMX Port of your Java process.

You need access to your linux machine via SSH login. All Communication will be tunneled over the SSH connection.

TIP: This Solution works no matter if there is a firewall or not.

Disadvantage: Everytime you restart your java process, you will need to do all steps from 4 - 9 again.

1. You need the putty-suite for your Windows machine from here:

http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

At least the putty.exe

2. Define one free Port on your linux machine:

<jmx-remote-port>

Example:

jmx-remote-port = 15666      

3. Add arguments to java process on the linux machine

This must be done exactly like this. If its done like below, it works for linux Machines behind firewalls (It works cause of the -Djava.rmi.server.hostname=localhost argument).

-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=<jmx-remote-port>
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.local.only=false
-Djava.rmi.server.hostname=localhost

Example:

java -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=15666 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.local.only=false -Djava.rmi.server.hostname=localhost ch.sushicutta.jmxremote.Main

4. Get Process-Id of your Java Process

ps -ef | grep <java-processname>

result ---> <process-id>

Example:

ps -ef | grep ch.sushicutta.jmxremote.Main

result ---> 24321

5. Find arbitrary Port for RMIServer stubs download

The java process opens a new TCP Port on the linux machine, where the RMI Server-Stubs will be available for download. This port also needs to be available via SSH Tunnel to get a connection to the Java Virtual Machine.

With netstat -lp this port can be found also the lsof -i gives hints what port has been opened form the java process.

NOTE: This port always changes when java process is started.

netstat -lp | grep <process-id>

tcp        0      0 *:<jmx-remote-port>     *:*     LISTEN      24321/java
tcp        0      0 *:<rmi-server-port>     *:*     LISTEN      24321/java


result ---> <rmi-server-port>

Example:

netstat -lp | grep 24321

tcp        0      0 *:15666     *:*     LISTEN      24321/java
tcp        0      0 *:37123     *:*     LISTEN      24321/java


result ---> 37123

6. Enable two SSH-Tunnels from your Windows machine with putty

Source port: <jmx-remote-port>
Destination: localhost:<jmx-remote-port>
[x] Local       
[x] Auto       

Source port: <rmi-server-port>
Destination: localhost:<rmi-server-port>
[x] Local       
[x] Auto

Example:

Source port: 15666
Destination: localhost:15666
[x] Local       
[x] Auto       

Source port: 37123
Destination: localhost:37123
[x] Local       
[x] Auto

7. Login to your Linux machine with Putty with this SSH-Tunnel enabled.

Leave the putty session open.

When you are logged in, Putty will tunnel all TCP-Connections to the linux machine over the SSH port 22.

JMX-Port:

Windows machine: localhost:15666   >>> SSH >>>   linux machine: localhost:15666

RMIServer-Stub-Port:

Windows Machine: localhost:37123   >>> SSH >>>   linux machine: localhost:37123

8. Start JConsole / Java VisualVM / Java Mission Control to connect to your Java Process using the following URL

This works, cause JConsole / Java VisualVM / Java Mission Control thinks you connect to a Port on your local Windows machine. but Putty send all payload to the port 15666 to your linux machine.

On the linux machine first the java process gives answer and send back the RMIServer Port. In this example 37123.

Then JConsole / Java VisualVM / Java Mission Control thinks it connects to localhost:37123 and putty will send the whole payload forward to the linux machine

The java Process answers and the connection is open.

[x] Remote Process:
service:jmx:rmi:///jndi/rmi://localhost:<jndi-remote-port>/jmxrmi

Example:

[x] Remote Process:
service:jmx:rmi:///jndi/rmi://localhost:15666/jmxrmi

9. ENJOY #8-]

Answer 6

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