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.

The query has been explained here.

How to force Docker for a clean build of an image?

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.

How to clean build an image in Docker?

To ensure that your build is completely rebuilt, 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 .

The 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

Method #3:

The command docker build --no-cache . solved our similar problem.

Our Dockerfile was:

RUN apt-get update
RUN apt-get -y install php5-fpm

But should have been:

RUN apt-get update && apt-get -y install php5-fpm

To prevent caching the update and installing separately.

Answer #4:

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 look 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 is required. So we should use them with caution 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 about 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.

How to force build Docker image?

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.

Query explanation:

I have built 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 with the same command, it’s using the build cache like:

Step 1 : FROM ubuntu:12.04
 ---> eb965dfb09d2
Step 2 : MAINTAINER Pavan Gupta <pavan.gupta@gmail.com>
 ---> Using cache
 ---> 4354ccf9dcd8
Step 3 : RUN apt-get update
 ---> Using cache
 ---> bcbca2fcf204
Step 4 : RUN apt-get install -y openjdk-7-jdk
 ---> Using cache
 ---> 103f1a261d44
Step 5 : RUN apt-get install -y openssh-server
 ---> Using cache
 ---> dde41f8d0904
Step 6 : RUN apt-get install -y git-core
 ---> Using cache
 ---> 9be002f08b6a
Step 7 : RUN apt-get install -y build-essential
 ---> Using cache
 ---> a752fd73a698
Step 8 : RUN apt-get install -y logrotate
 ---> Using cache
 ---> 93bca09b509d
Step 9 : RUN apt-get install -y lsb-release
 ---> Using cache
 ---> fd4d10cf18bc
Step 10 : RUN mkdir /var/run/sshd
 ---> Using cache
 ---> 63b4ecc39ff0
Step 11 : RUN echo 'root:root' | chpasswd
 ---> Using cache
 ---> 9532e31518a6
Step 12 : RUN sed -i 's/PermitRootLogin without-password/PermitRootLogin yes/' /etc/ssh/sshd_config
 ---> Using cache
 ---> 47d1660bd544
Step 13 : RUN sed 's@session\s*required\s*pam_loginuid.so@session optional pam_loginuid.so@g' -i /etc/pam.d/sshd
 ---> Using cache
 ---> d1f97f1c52f7
Step 14 : RUN wget -O aerospike.tgz 'http://aerospike.com/download/server/latest/artifact/ubuntu12'
 ---> Using cache
 ---> bd7dde7a98b9
Step 15 : RUN tar -xvf aerospike.tgz
 ---> Using cache
 ---> 54adaa09921f
Step 16 : RUN dpkg -i aerospike-server-community-*/*.deb
 ---> Using cache
 ---> 11aba013eea5
Step 17 : EXPOSE 22 3000 3001 3002 3003
 ---> Using cache
 ---> e33aaa78a931
Step 18 : CMD /usr/sbin/sshd -D
 ---> Using cache
 ---> 25f5fe70fa84
Successfully built 25f5fe70fa84

The cache shows that an aerospike is installed. However, I don’t find it inside containers spawned from this image, so I want to rebuild this image without using the cache. How can I force Docker to rebuild a clean image without the cache?

Hope you learned something from this post.

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About ᴾᴿᴼᵍʳᵃᵐᵐᵉʳ

Linux and Python enthusiast, in love with open source since 2014, Writer at programming-articles.com, India.

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