239
votes

How to activate JMX on a JVM for access with jconsole?

12
it is allowd, and actually it is only a reminder for me, because I always forget where to copy the parameters from and now I know where I find it :-)Mauli
Stack Exchange has always explicitly encouraged users to answer their own questions, see here: stackoverflow.com/help/self-answerTim Büthe
More than once I have searched SO for something and found a question answered... by myself. And one of those was asked by me as well. This is why it is good to put your own answers in. Also, think of all the other people that may have encountered your problem, if you answer your question you will be helping them too.Mike Miller
Updated doc for Java 8 is hereAndrew Johnston
@Mauren: Can you provide a reference to your closed question you answered yourself? It might be worth discussing on Meta.kevinarpe

12 Answers

306
votes

The relevant documentation can be found here:

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

Start your program with following parameters:

-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=9010
-Dcom.sun.management.jmxremote.rmi.port=9010
-Dcom.sun.management.jmxremote.local.only=false
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false

For instance like this:

java -Dcom.sun.management.jmxremote \
  -Dcom.sun.management.jmxremote.port=9010 \
  -Dcom.sun.management.jmxremote.local.only=false \
  -Dcom.sun.management.jmxremote.authenticate=false \
  -Dcom.sun.management.jmxremote.ssl=false \
  -jar Notepad.jar

-Dcom.sun.management.jmxremote.local.only=false is not necessarily required but without it, it doesn't work on Ubuntu. The error would be something like this:

01 Oct 2008 2:16:22 PM sun.rmi.transport. customer .TCPTransport$AcceptLoop executeAcceptLoop
WARNING: RMI TCP Accept-0: accept loop for ServerSocket[addr=0.0.0.0/0.0.0.0,port=0,localport=37278] throws
java.io.IOException: The server sockets created using the LocalRMIServerSocketFactory only accept connections from clients running on the host where the RMI remote objects have been exported.
    at sun.management.jmxremote.LocalRMIServerSocketFactory$1.accept(LocalRMIServerSocketFactory.java:89)
    at sun.rmi.transport. customer .TCPTransport$AcceptLoop.executeAcceptLoop(TCPTransport.java:387)
    at sun.rmi.transport. customer .TCPTransport$AcceptLoop.run(TCPTransport.java:359)
    at java.lang.Thread.run(Thread.java:636)

see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6754672

Also be careful with -Dcom.sun.management.jmxremote.authenticate=false which makes access available for anyone, but if you only use it to track the JVM on your local machine it doesn't matter.

Update:

In some cases I was not able to reach the server. This was then fixed if I set this parameter as well: -Djava.rmi.server.hostname=127.0.0.1

73
votes

Running in a Docker container introduced a whole slew of additional problems for connecting so hopefully this helps someone. I ended up needed to add the following options which I'll explain below:

-Dcom.sun.management.jmxremote=true
-Dcom.sun.management.jmxremote.local.only=false
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
-Djava.rmi.server.hostname=${DOCKER_HOST_IP}
-Dcom.sun.management.jmxremote.port=9999
-Dcom.sun.management.jmxremote.rmi.port=9998

DOCKER_HOST_IP

Unlike using jconsole locally, you have to advertise a different IP than you'll probably see from within the container. You'll need to replace ${DOCKER_HOST_IP} with the externally resolvable IP (DNS Name) of your Docker host.

JMX Remote & RMI Ports

It looks like JMX also requires access to a remote management interface (jstat) that uses a different port to transfer some data when arbitrating the connection. I didn't see anywhere immediately obvious in jconsole to set this value. In the linked article the process was:

  • Try and connect from jconsole with logging enabled
  • Fail
  • Figure out which port jconsole attempted to use
  • Use iptables/firewall rules as necessary to allow that port to connect

While that works, it's certainly not an automatable solution. I opted for an upgrade from jconsole to VisualVM since it let's you to explicitly specify the port on which jstatd is running. In VisualVM, add a New Remote Host and update it with values that correlate to the ones specified above:

Add Remote Host

Then right-click the new Remote Host Connection and Add JMX Connection...

Add JMX Connection

Don't forget to check the checkbox for Do not require SSL connection. Hopefully, that should allow you to connect.

10
votes

Note, Java 6 in the latest incarnation allows for jconsole to attach itself to a running process even after it has been started without JMX incantations.

If that is available to you, also consider jvisualvm as it provides a wealth of information on running processes, including a profiler.

7
votes

I'm using WAS ND 7.0

My JVM need all the following arguments to be monitored in JConsole

    -Djavax.management.builder.initial= 
    -Dcom.sun.management.jmxremote 
    -Dcom.sun.management.jmxremote.port=8855 
    -Dcom.sun.management.jmxremote.authenticate=false 
    -Dcom.sun.management.jmxremote.ssl=false
6
votes

On Linux, I used the following params:

-Djavax.management.builder.initial= 
-Dcom.sun.management.jmxremote 
-Dcom.sun.management.jmxremote.port=9010 
-Dcom.sun.management.jmxremote.local.only=false
-Dcom.sun.management.jmxremote.authenticate=false 
-Dcom.sun.management.jmxremote.ssl=false

and also I edited /etc/hosts so that the hostname resolves to the host address (192.168.0.x) rather than the loopback address (127.0.0.1)

2
votes

Run your java application with the following command line parameters:

-Dcom.sun.management.jmxremote.port=8855
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false

It is important to use the -Dcom.sun.management.jmxremote.ssl=false parameter if you don't want to setup digital certificates on the jmx host.

If you started your application on a machine having IP address 192.168.0.1, open jconsole, put 192.168.0.1:8855 in the Remote Process field, and click Connect.

2
votes

along with below command line parameters ,

-Dcom.sun.management.jmxremote.port=9999
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false

Sometimes in the linux servers , imx connection doesn't get succeeded. that is because , in cloud linux host, in /etc/hosts so that the hostname resolves to the host address.

the best way to fix it is, ping the particular linux server from other machine in network and use that host IP address in the

-Djava.rmi.server.hostname=IP address that obtained when you ping that linux server.

But never rely on the ipaddress that you get from linux server using ifconfig.me. the ip that you get there is masked one which is present in the host file.

2
votes

Step 1: Run the application using following parameters.

-Dcom.sun.management.jmxremote.port=9999 
-Dcom.sun.management.jmxremote.authenticate=false 
-Dcom.sun.management.jmxremote.ssl=false

Above arguments bind the application to the port 9999.

Step 2: Launch jconsole by executing the command jconsole in command prompt or terminal.

Select ‘Remote Process:’ and enter the url as {IP_Address}:9999 and click on Connect button to connect to the remote application.

You can refer this link for complete application.

2
votes

The below options works for me:

-Dcom.sun.management.jmxremote=true
-Dcom.sun.management.jmxremote.port=9010
-Dcom.sun.management.jmxremote.rmi.port=9010
-Dcom.sun.management.jmxremote.local.only=false
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
-Djava.rmi.server.hostname={host name}

and remember to open 9010 port in the server

sudo ufw allow 9010/udp
sudo ufw allow 9010/tcp
sudo ufw reload
1
votes

First you need to check if your java process is already running with JMX parameters. Do this:

ps -ef | grep java

Check your java process you need to monitor. If you can see jmx rmi parameter Djmx.rmi.registry.port=xxxx then use the port mentioned here in your java visualvm to connect it remotely under jmx connection.

If it's not running through jmx rmi port then you need to run your java process with below mentioned parameters :

-Djmx.rmi.registry.port=1234 -Djmx.rmi.port=1235 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false

Note: port numbers are based on your choice.

Now you can use this port for jmx coneection. Here it is port 1234.

0
votes

I had this exact issue, and created a GitHub project for testing and figuring out the correct settings.

It contains a working Dockerfile with supporting scripts, and a simple docker-compose.yml for quick testing.

0
votes

RUN LOCAL PROCESS JCONSOLE using Remote Process option

To run locally, this worked for me -

I added this in my vm args -

-Dcom.sun.management.jmxremote=true
-Dcom.sun.management.jmxremote.port=6001
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
-Djava.rmi.server.hostname=localhost
-Dcom.sun.management.jmxremote.rmi.port=6001

I opened JConsole via Intellij Terminal
It was showing me all PID's in grey in local
So I selected remote process and logged in using host - localhost:6001
Keep empty username & password
Then click connect
  • Make sure no other process is running on port 6001. You can also use other ports.