Clear Docker Buildx Cache21 Aug 2020
You might have encountered a situation where you cannot build the latest Docker image when using the Buildx. If so, you may find this article helpful to give you a little insight into your question, “Why I keep seeing the stale image in the list!”.
What I tried was building the Docker image supporting ARM64 architecture. To achieve my goal, it requires me to enable Buildx experimental feature of Docker. It allows us to build a Docker image supporting multiple architectures. When I have found a problem in the image, I wanted to change the Dockerfile to reflect the fix I applied. But it failed. As shown in the following output, the
CREATED time of the images keeps the past time even I have created just a few seconds before.
$ docker images REPOSITORY TAG IMAGE ID CREATED SIZE presto 341-SNAPSHOT c15822305160 5 hours ago 1.05GB lewuathe/presto-worker 341-SNAPSHOT eb1d11521b04 5 hours ago 1.38GB lewuathe/presto-coordinator 341-SNAPSHOT 8e0085374165 5 hours ago 1.38GB
That’s was so annoying that I could not test my fix was adequately resolving the issue. Here are two options to overcome this stressful situation.
Build without any cache
As well as normal build command,
buildx also provides
--no-cache option. It enables us to build an image from scratch. The latest image will be created for sure.
$ docker buildx build \ --no-cache \ # Without using cache --platform linux/arm64/v8 \ -f Dockerfile-arm64v8 \ -t lewuathe/prestobase:340-SNAPSHOT-arm64v8
Clearing the cache completely
Another option is clearing the cache. However, it has a side-effect affecting other image build time. Since removing all layer caches, it can make the build time for other images longer. But if the images you are holding is not so many, deleting the cache can be a reasonable option.
The builder instance holds the cache. The following command will clear the cache hold by all builders.
$ docker builder prune --all
Afterward, you can build the image as usual. We can see the build time is refreshed as follows.
$ docker images REPOSITORY TAG IMAGE ID CREATED SIZE presto 341-SNAPSHOT c15822305160 a second ago 1.05GB lewuathe/presto-worker 341-SNAPSHOT eb1d11521b04 a second ago 1.38GB lewuathe/presto-coordinator 341-SNAPSHOT 8e0085374165 a second ago 1.38GB
To learn the practical techniques of Docker, you may find the following guide from Manning useful. Docker has many options or configurations. If you know these details, Docker will be more attentive tool for you.
Thanks for reading as usual!