How to mount a host directory in a Docker container

Question

I am trying to mount a host directory into a Docker container so that any updates done on the host is reflected into the Docker containers.

Where am I doing somethin

Answer 1

There are a couple ways you can do this. The simplest way to do so is to use the dockerfile ADD command like so:

ADD . /path/inside/docker/container

However, any changes made to this directory on the host after building the dockerfile will not show up in the container. This is because when building a container, docker compresses the directory into a .tar and uploads that context into the container permanently.

The second way to do this is the way you attempted, which is to mount a volume. Due to trying to be as portable as possible you cannot map a host directory to a docker container directory within a dockerfile, because the host directory can change depending on which machine you are running on. To map a host directory to a docker container directory you need to use the -v flag when using docker run like so:

docker run -v /host/directory:/container/directory -other -options image_name command_to_run