Actually I wanted a solution working for JEE containers, specifically for Glassfish, but after I tried many combinations of settings and did not succeed, I reduced the setup to the simplest possible case.
Here is my Hello World daemon started in a Docker container. I want to attach jconsole or VisulaVM to it. Everything is on the same machine.
public class Main {
public static void main(String[] args) {
while (true) {
try {
Thread.sleep(3000);
System.out.println("Hello, World");
} catch (InterruptedException e) {
break;
}
}
}
}
Dockerfile
FROM java:8
COPY . /usr/src/myapp
WORKDIR /usr/src/myapp
RUN javac Main.java
CMD ["java", "Main"]
Building: docker build -t hello-world-daemon .
Running: docker run -it --rm --name hwd hello-world-daemon
Questions:
- what JVM parameters should be added to
CMDcommand line? - what ports should be exposed and published?
- what network mode should Docker container be using?
I do not show my failed attempts here so that correct answers will not be biased. This should be a pretty common problem, yet I could not find a working solution.
Update. Worked solution
This Dockerfile works
FROM java:8
COPY . /usr/src/myapp
WORKDIR /usr/src/myapp
RUN javac Main.java
CMD ["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", "Main"]
EXPOSE 9010
in combination with the docker run command
docker run -it --rm --name hwd -p 9010:9010 hello-world-daemon
VisualVM connects via right click Local->Add JMX Connection, and then entering localhost:9010, or through adding a remote host.
JConsole connects via selecting a Remote process with localhost:9010.
When defining the connection as remote, any interface listed by ifconfig can be used. For instance, docker0 interface with address 172.17.0.1 works. The container's address 172.17.0.2 works too.
