Docker Compose on Mac - Image Location

Question

I use docker-compose for local development on my Mac. I have multiple images being built with docker compose. My docker and docker-compose set up is very standard. Now I want to share my locally built image file with someone. Where are these local files stored?

Searching a bit gave me answers like:

~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2

But then how can I extract one image from this and share? I tried running the tty that is present with it, but to no avail.

Docker Version: 18.03 Docker for Mac

Docker compose Version: 2

Answer 1

If you have docker-hub account (which is free), then you can use docker push command to save docker image into registry and use docker pull to pull on other machine.

Another solution is to use save + import commands.

For that you can use docker save and docker import commands.

docker@default:~$ docker save --help

Usage:  docker save [OPTIONS] IMAGE [IMAGE...]

Save one or more images to a tar archive (streamed to STDOUT by default)

Options:
  -o, --output string   Write to a file, instead of STDOUT
docker@default:~$

After that you have TAR file on your file system (check -o value) then transfer the file to another machine and execute docker import

docker@default:~$ docker import --help

Usage:  docker import [OPTIONS] file|URL|- [REPOSITORY[:TAG]]

Import the contents from a tarball to create a filesystem image

Options:
  -c, --change list      Apply Dockerfile instruction to the created image
  -m, --message string   Set commit message for imported image
docker@default:~$

Answer 2

Apparently, the solution with docker-compose is using the docker save command. We do not need to know the locations of images as @fly2matrix mentioned. We can use the docker save command to save the image in TAR file.

docker save --output image-name.tar image-name:tag

Then this image can be shared and loaded by other users through:

docker load --input image-name.tar