How to force Docker for a clean build of an image

There's a --no-cache option:

docker build --no-cache -t u12_core -f u12_core .

In older versions of Docker you needed to pass --no-cache=true, but this is no longer the case.

In some extreme cases, your only way around recurring build failures is by running:

docker system prune

The command will ask you for your confirmation:

WARNING! This will remove:
    - all stopped containers
    - all volumes not used by at least one container
    - all networks not used by at least one container
    - all images without at least one container associated to them
Are you sure you want to continue? [y/N]

This is of course not a direct answer to the question, but might save some lives... It did save mine.

To ensure that your build is completely rebuild, including checking the base image for updates, use the following options when building:

--no-cache - This will force rebuilding of layers already available

--pull - This will trigger a pull of the base image referenced using FROM ensuring you got the latest version.

The full command will therefore look like this:

docker build --pull --no-cache --tag myimage:version .

Same options are available for docker-compose:

docker-compose build --no-cache --pull

Note that if your docker-compose file references an image, the --pull option will not actually pull the image if there is one already.

To force docker-compose to re-pull this, you can run:

docker-compose pull