I am running a Java application on Java 6 VM on a remote Windows XP, on which I can run jvisualvm.exe to connect to the running application automatically.
Now I need to connect that application from my local computer, but I don't know the JMX port number of the remote computer. Where can I find it? Or, must I restart that application with some VM parameters to specify the port number?
After reading the question How to find the JMX port in a server, I executed the command on the remote computer
netstat -apn
but got nothing.
Now I need to connect that application from my local computer, but I don't know the JMX port number of the remote computer. Where can I find it? Or, must I restart that application with some VM parameters to specify the port number?
By default JMX does not publish on a port unless you specify the arguments from this page: How to activate JMX...
-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
-Djava.rmi.server.hostname=localhost
NOTE: you need to be careful of the security ramifications of some of the above settings.
Also, if you are running you should be able to access any of those system properties to see if they have been set:
if (System.getProperty("com.sun.management.jmxremote") == null) {
System.out.println("JMX remote is disabled");
} else [
String portString = System.getProperty("com.sun.management.jmxremote.port");
if (portString != null) {
System.out.println("JMX running on port "
+ Integer.parseInt(portString));
}
}
Depending on how the server is connected, you might also have to specify the following parameter. As part of the initial JMX connection, jconsole connects up to the RMI port to determine which port the JMX server is running on. When you initially start up a JMX enabled application, it looks its own hostname to determine what address to return in that initial RMI transaction. If your hostname is not in /etc/hosts or if it is set to an incorrect interface address then you can override it with the following:
-Djava.rmi.server.hostname=<IP address>
As an aside, my SimpleJMX package allows you to define both the JMX server and the RMI port or set them both to the same port. The above port defined with com.sun.management.jmxremote.port is actually the RMI port. This tells the client what port the JMX server is running on.
Related
My understanding is that tomcat server can be accessed thru jmxrmi if we configure following properties. Port can also be configured.
-Dcom.sun.management.jmxremote.port=30000
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.authenticate=true
-Dcom.sun.management.jmxremote.password.file=xyz
-Dcom.sun.management.jmxremote.access.file=xyz
After that tomcat server can be connected thru some jmx tools like jconsole or jvisualvm etc. But I also noticed that same tomcat server can also be connected on default jmxrmi port 1099. I havent configured anywhere port 1099. Even though if I comment out all above properties, I see tomcat still can be connected to on port 1099 on jvisualvm.
Please suggest, what might be enabling this connectivity on default port. And how can I disable this connectivity?
Possibly some other third party libraries in classpath might be doing it, but how to figure which one?
JMX uses two ports: one for the JMX connection (which you have set to port 30000) and another one for RMI communications. Java defaults to port 1099, but if it's in use, it will choose the first port available after 1099. In Java 8, you cannot explicitly set this port via system properties.
For later Java versions, you can use the system property com.sun.management.jmxremote.rmi.port.
Tomcat has a workaround for this. You can use the JmxRemoteLifecycleListener to set the rmiServerPortPlatform attribute. Set that to whatever port you prefer.
Note that you cannot disable this second port: it is required for JMX to operate properly.
Assuming I have a server in my local network with ip 192.168.100.10.
There is docker container running in it with java application.
Now i want to connect to this java application with VisualVM from my computer which has ip address 192.168.100.20. I thought I had everything configured properly but it still does not work.
I have passed these JVM options:
-Dcom.sun.management.jmxremote"
-Dcom.sun.management.jmxremote.port=9010"
-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=9010"
-Djava.rmi.server.hostname=192.168.100.10"
Then I have exposed port 9010 in Dockerfile:
EXPOSE 9010
Then added this port to docker-compose:
ports:
- "9010:9010"
I am trying to connect to remote host with JConsole or VisualVM from my local machine. In "Remote Process" input in JConsole I put "192.168.100.10:9010" but connection fails with error:
"The connection to 192.168.100.10:9010 did not succeed. Would you like to try again?"
What am I doing wrong?
The solution above is sufficient and working. I've been using env variable to set port number which was not working properly.
i want to profile my web application now this is what i do:
run jpenable.exe and after it finds thi jvm, it gives me a port so i can connect to it using JProfiler GUI(for instance:12121)! now as I want to have commandline control i then try to connect jpcontroller using this command:
jpcontroller.exe localhost:12121
but it cannot connect and sticks there with no error! now if i use this command:
jpcontroller.exe <port>
then it works!
but actually i can't do this as i want to connect to a remote jvm!!
am i wrong some where?
jpcontroller does not connect to the port that is opened by the profiling agent, but it uses JMX to connect to the process. For that to work on a remote computer, add the VM parameter
-Djprofiler.jmxServerPort=[port]
to the profiled process and use that port in jpcontroller. Then, an MBean server will be created that listens on that port.
Sorry for this question which must have been asked many times, but I can't succeed in resolving my problem.
I've read a lot of blogs, sites, forums, .... and didn't find any solution in my case.
Case :
I need to connect VisualVM on my box to distant servers (tomcats, weblogics) for performance / threads / memory monitoring.
Those servers are installed on (physical or virtual) machines which are protected by a firewall.
Large intervals of ports are open in the firewall and can be used, but not all ports.
Tests
I've tried direct connections through JMX in VisualVM, using following JVM options on the server-side at server startup :
-Djava.rmi.server.hostname=[hostname]
-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=[port]
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.authenticate=false
I've precised the hostname because from my network the hostname and the IP address of the server are not the same than those from the network of the remote server.
No success, VisualVM always seems searching for an unknown server.
tried starting jstatd on the server-side on a port accessible (-p option) from my box (telnet on this port works), but when launching visualVM on this host with the jstatd port, it still seems waiting for something unreachable.... Same behavior with jps connecting to this remote host.
tried using the same tools on a server with less network protection, and it works. So I have seen the connections between my box and the server and they are done on ports different from what I've specified to jstatd.
I understand that this port is needed for first communication (kind of handshake) and real communications are done on other ports, but not predictible (ex: 60305, 55197, ...).
Not sure I understand very well how RMI works.
Please, help me, I'm going crazy !
Unfortunately JMX tries to open ports other than the one you configure. Just yesterday I succeeded connecting to tomcat behind firewall via JMX. The two tricky parts are:
put a file called jmxremote.access in CATALINA_HOME/conf, which contains the following lines:
monitorRole readonly
controlRole readwrite
in server.xml set the ports that will be used by jmx, via a special tomcat listener (catalina-jmx-remote.jar required in /lib):
<Listener className="org.apache.catalina.mbeans.JmxRemoteLifecycleListener"
rmiRegistryPortPlatform="9009" rmiServerPortPlatform="9010" />
Then open these two ports on the firewall. It works. But that's just for tomcat.
Another option is to use ssh tunnelling. In short - you connect via SSH and configure it to forward some local port (where the jmx client is running) to some ports on the other side of the tunnel.
References:
Connecting to JMX on Tomcat 6 through a firewall
Connecting MySQL server on Amazon EC2 instance using ssh tunnel
Here are the steps to do this:
Launch an ejstatd in your remote host this way (in ejstatd folder): mvn exec:java -Djava.rmi.server.hostname=[remote_host_name] -Dexec.args="-pr 1099 -ph 1100 -pv 1101" (used for "jstatd" type connection)
Launch your Java application with those additional Java parameters: -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.port=1102 -Dcom.sun.management.jmxremote.rmi.port=1102 -Djava.rmi.server.hostname=[remote_host_name] (used for "JMX" type connection) (java.rmi.server.hostname is required here only because the IP and hostname from your network is not the same as the server point of view)
Open those 4 ports on your remote host and make them available to your local machine: 1099, 1100, 1101 and 1102
Launch JVisualVM
Right-click on "Remote" > "Add Remote Host..." and enter your remote host name in "Host name" (if you don't use the port 1099, you can change this in the "Advanced Settings")
Right-click on the remote host you've just created > "Add JMX Connection..." and enter "[remote_host_name]:1102" in "Connection" input, and check "Do not require SSL connection"
Your Java process will appear twice: one from the "jstatd" connection type, and one from the "JMX" connection type.
Disclaimer: I'm the author of the open source ejstatd tool.
On your [hostname], open up [port] and tcp port range 40000-60000 for your IP only.
This did the trick for me fairly well.
I have an application running in server A. The dev environment is in server B.
I am trying to do remote debugging of app running in server A.
In server A i added following command to service start script
-Xdebug -Xnoagent -Xrunjdwp:transport=dt_socket,address=4554,server=y,suspend=n
And service is running in server A.
When i try to launch remote debugging configuration it gives
Failed to connect to remote VM. Connection refused. Connection refused
port 4554 is free in server A.
What other configuration need to be done for this?
Regards
Dheeraj Joshi
Try this.
Set suspend=y, just to make sure you got the JVM line right. This should stop the VM on startup until you connect.
If you're on Unix, bring up the terminal and try telnet [host] [port] - this will quickly let you know if there's anything listening to that port on that host.
Make sure the connection properties in Eclipse are set correctly. Note that the port defaults to 8000.
Use the IP address instead of the host name, to rule out DNS/hostfile problems.
Another way of starting the JVM that I use successfully is:
-agentlib:jdwp=transport=dt_socket,address=8000,server=y,suspend=y
Check if there is a firewall between and/or on the two servers.