What is the difference between expose and publish in Docker

Question

I’m experimenting with dockerfiles and the use of expose and publish has been a major confusion.

In all the tutorials they first include the EXPOSE command in the dockerfile and then build an image from this dockerfile

$ docker build -t an_image - < Dockerfile

And then publish the same port as above when running the image

$ docker run -d -p 8080 an_image

Answer 1

Basically, you have three options:

• Neither specify EXPOSE nor -p -> If you do not specify any of those, the service in the     container will not be accessible from anywhere except from inside the container itself.
• Only specify EXPOSE -> If you EXPOSE a port, the service in the container is not accessible from outside Docker, but from inside other Docker containers. So this is good for inter-container communication.
• Specify EXPOSE and -p -> If you EXPOSE and -p a port, the service in the container is accessible from anywhere, even outside Docker.