How do I attach VisualVM to a simple Java process running in a Docker container

At first you should run you application with these JVM params:

-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

Then you should expose port for docker:

EXPOSE 9010

Also specify port binding with docker run command:

docker run -p 9010:9010 -it --rm --name hwd hello-world-daemon

After that you can connect with Jconsole to local 9010 port and manage application run in Docker.

I followed an other SO response to a similar question and it worked.

I started my Java process inside the container by adding those JVM params:

-Dcom.sun.management.jmxremote.port=<port> \-Dcom.sun.management.jmxremote.authenticate=false \-Dcom.sun.management.jmxremote.ssl=false \-Dcom.sun.management.jmxremote.rmi.port=<port> \-Djava.rmi.server.hostname=$HOST_HOSTNAME

and started the Docker container specifying -e HOST_HOSTNAME=$HOSTNAME -p <port> to the docker run command.

Then I've been able to access to this remote Java app from my local JVisualVm by adding a remote JMX connection ("File" > "Add a JMX Connection...") and specifying <dockerhostname>:<port> in the "Connection" input, and checking "Do not require SSL connection".

FWIW, this is how I was able to attach VisualVM to a Java process inside a Docker container running on macOS:

Main.java:

public class Main {    public static void main(String args[]) throws Exception {        while (true) {            System.out.print("Hello ");            System.out.println("world");            Thread.sleep(1000);        }    }}

Dockerfile:

FROM openjdk:11.0.2-slimCOPY Main.class /WORKDIR /ENTRYPOINT ["java", \"-Dcom.sun.management.jmxremote=true", \"-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", \"-Dcom.sun.management.jmxremote.rmi.port=9010", \"-Djava.rmi.server.hostname=localhost", \"Main"]

Compile the Java code, build the image and run the container like this:

$ javac Main.java$ docker build -t main .$ docker run -p 9010:9010 -it main

Then attach VisualVM using JMX to localhost:9010