1.3 KiB
| title | date | draft | images |
|---|---|---|---|
| Advanced Docker Image Construction with Bash | 2019-12-26T21:01:37-05:00 | false |
On current versions of Docker, you can't mount volumes during image construction. This poses an issue for me as I don't want to replicate gigabytes of data already existing on my disk when it won't appear on the final build. Therefore, instead of building an image with a traditional Dockerfile, we're going to use a bash script on a running base image container and export the filesystem to create the image from.
So first run the base image with the mounts that you want
docker run -v /mnt:/mnt -td --name containername baseimage /bin/bash
Then copy whatever setup script you have and execute it on the running container
docker cp setup containername:/setup
docker exec -it containername /setup
Once the setup script finalizes, we can export the container filesystem into a file called image.tar
docker export --output="image.tar" containername
Once we've exported the filesystem, we can get rid of the existing container
docker stop containername && docker rm containername
Now create a Dockerfile with the following:
FROM scratch
ADD image.tar /
CMD ["bin/bash"]
Now you can create the image by building the Dockerfile
docker build -t finalimagename .