I just ran docker buildx build and it ran for about 10 minutes, but yet when I try to clear the build cache, it keeps saying that 0B was reclaimed. I'm obviously misunderstanding something here.
Here's my total output:
ubuntu@ip-10-20-65-45:~$ docker buildx build --platform linux/arm/v7 .
WARN[0000] No output specified for docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load
[+] Building 6000.2s (5/5) FINISHED
=> [internal] load build definition from Dockerfile 0.1s
=> => transferring dockerfile: 32B 0.0s
=> [internal] load .dockerignore 0.0s
=> => transferring context: 2B 0.0s
=> [internal] load metadata for docker.io/kalilinux/kali-rolling:latest 1.1s
=> CACHED [1/2] FROM docker.io/kalilinux/kali-rolling@sha256:8ce5177e07c182e6635cf303f8e3daceface00f0f40b27c34ab033cfb49bcbbd 0.0s
=> => resolve docker.io/kalilinux/kali-rolling@sha256:8ce5177e07c182e6635cf303f8e3daceface00f0f40b27c34ab033cfb49bcbbd 0.0s
=> [2/2] RUN apt update && apt dist-upgrade -y -o Dpkg::Options::="--force-confdef" -o Dpkg::Options::="--force-confold" && apt autoremove -y && apt clean -y && if [ "linux/arm/v7" = "linux/arm/v7" ] ; then apt install wget -y && wget http://ftp.us.debian.org/debian/pool/main/libs/libseccomp/libseccomp2_2.5.1-1_armhf.deb -O lib 5999.0s
ubuntu@ip-10-20-65-45:~$ docker builder prune
WARNING! This will remove all dangling build cache. Are you sure you want to continue? [y/N] y
Total reclaimed space: 0B
ubuntu@ip-10-20-65-45:~$ docker build prune
unable to prepare context: path "prune" not found
ubuntu@ip-10-20-65-45:~$ docker image ls -a
REPOSITORY TAG IMAGE ID CREATED SIZE
moby/buildkit buildx-stable-1 cf14c5e88c0e 2 weeks ago 123MB
ubuntu@ip-10-20-65-45:~$ docker builder prune -a
WARNING! This will remove all build cache. Are you sure you want to continue? [y/N] y
Total reclaimed space: 0B
ubuntu@ip-10-20-65-45:~$ docker builder prune -af
Total reclaimed space: 0B
ubuntu@ip-10-20-65-45:~$ docker buildx prune -af
ID RECLAIMABLE SIZE LAST ACCESSED
r9fb1b3q8jmu7ann44vvjtpi5* true 4.10kB
xiw6rtbwe2xtd9s8xghdgcz70 true 154.88MB
Total: 154.88MB
ubuntu@ip-10-20-65-45:~$
The most I was able to get back was 154MB, but I know these images are much bigger than this. How do I properly clear out the cache from docker buildx build?