How to force Docker for a clean build of an image

Question

I have build a Docker image from a Docker file using the below command.

$ docker build -t u12_core -f u12_core .

When I am trying to rebuild it

Answer 1

With docker-compose try docker-compose up -d --build --force-recreate

Answer 2

GUI-driven approach: Open the docker desktop tool (that usually comes with Docker):

1. under "Containers / Apps" stop all running instances of that image
2. under "Images" remove the build image (hover over the box name to get a context menu), eventually also the underlying base image

Answer 3

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.

Answer 4

I would not recommend using --no-cache in your case.

You are running a couple of installations from step 3 to 9 (I would, by the way, prefer using a one liner) and if you don't want the overhead of re-running these steps each time you are building your image you can modify your Dockerfile with a temporary step prior to your wget instruction.

I use to do something like RUN ls . and change it to RUN ls ./ then RUN ls ./. and so on for each modification done on the tarball retrieved by wget

You can of course do something like RUN echo 'test1' > test && rm test increasing the number in 'test1 for each iteration.

It looks dirty, but as far as I know it's the most efficient way to continue benefiting from the cache system of Docker, which saves time when you have many layers...

Answer 5

Most of information here are correct.
Here a compilation of them and my way of using them.

The idea is to stick to the recommended approach (build specific and no impact on other stored docker objects) and to try the more radical approach (not build specific and with impact on other stored docker objects) when it is not enough.

Recommended approach :

1) Force the execution of each step/instruction in the Dockerfile :

docker build --no-cache 

or with docker-compose build :

docker-compose build --no-cache

We could also combine that to the up sub-command that recreate all containers:

docker-compose build --no-cache &&
docker-compose up -d --force-recreate 

These way don't use cache but for the docker builder and the base image referenced with the FROM instruction.

2) Wipe the docker builder cache (if we use Buildkit we very probably need that) :

docker builder prune -af

3) If we don't want to use the cache of the parent images, we may try to delete them such as :

docker image rm -f fooParentImage

In most of cases, these 3 things are perfectly enough to allow a clean build of our image.
So we should try to stick to that.

More radical approach :

In corner cases where it seems that some objects in the docker cache are still used during the build and that looks repeatable, we should try to understand the cause to be able to wipe the missing part very specifically. If we really don't find a way to rebuild from scratch, there are other ways but it is important to remember that these generally delete much more than it is required. So we should use them with cautious overall when we are not in a local/dev environment.

1) Remove all images without at least one container associated to them :

docker image prune -a

2) Remove many more things :

docker system prune -a

That says :

WARNING! This will remove:
  - all stopped containers
  - all networks not used by at least one container
  - all images without at least one container associated to them
  - all build cache

Using that super delete command may not be enough because it strongly depends on the state of containers (running or not). When that command is not enough, I try to think carefully which docker containers could cause side effects to our docker build and to allow these containers to be exited in order to allow them to be removed with the command.

Answer 6

You can manage the builder cache with docker builder

To clean all the cache with no prompt: docker builder prune -af