Connecting Eclipse to Docker Container for Remote Debugging

Question

I'm trying to connect eclipse to a docker container I have running but I am having trouble.

My docker run command is as follows:

docker run --rm -it -p 8000:8000 -p=8668:8080 -p 8010:8009 -p 8443:8443 \
--name myContainer -h theContainer -e JVM_ROUTE=myContainer1 myContainer:qa

In eclipse, I'm connecting with localhost as the host, and 8000 as the port. I go to Run->Debug Configurations->Remote Java Application, and I've created a new debug configuration.

When I click apply, then debug, I get a pop up error message Failed to connect to remote VM.

What else do I need to do to get remote debugging working properly?

Answer 1

A java application running in a docker container can be remotely debugged by

1. Enabling JDWP for the java process in the container, e.g.

   java -Xdebug -Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=y [...]
   

   or using the JAVA_OPTS environment variable

   JAVA_OPTS="-Xdebug -Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=y"
   

   Note that suspend=y will prevent the application from starting until a remote debugger is attached to the JVM. If suspend=n is used, the application will start as normal allowing a remote debugger to connect at a later time.

2. Connecting to the process, e.g. through your IDE, using the port specified in the address=<port> settings above, and importantly the ip address of the docker host which, unless you are running on linux, is probably not localhost. If you are using docker-machine, the docker host ip can be displayed using docker-machine ip, e.g.

   $ docker-machine ip
   192.168.99.100