Bind container port to host inside Dockerfile

Question

Normally when binding port, I would do docker run -p hostport:dockerport ..., but can I specify the port binding inside my Dockerfile ?

I'm starting a server that listens on a port. The server takes the port through cmd line arguments. It would be great if I don't have to repeat the port in two places (in docker run command and in Dockerfile)

Answer 1

In dockerfile you can only use expose. The EXPOSE instruction informs Docker that the container listens on the specified network ports at runtime. EXPOSE does not make the ports of the container accessible to the host.

To allocate Hostport to container you need to do publish (-p). Or the -P flag to publish all of the exposed ports.

To automate the process, You can use docker-compose. In docker compose file you can orchestrate multiple docker run commands with different arguments.