Can the default docker driver be used with remote cache?

[mforeman19]

I have a use case where I need to load an image locally, but I'd also like to take advantage of pulling cache from a remote registry. I've noticed that using the docker-container driver is somewhat slow when it comes to loading an image locally after a build whereas hitting the default docker driver is way faster.

However, I noticed that using the default driver + trying to pull remote cache doesn't seem to work? Using the same build configurations, I was not observing the default driver builds actually attempting to pull remote cache despite pulling the manifest.

Sample command:

docker buildx build --target final --load --cache-from type=registry,ref={INSERT REMOTE CACHE}  .

Where before running the above, a docker builder instance is pointed at that uses the docker-container driver (allowing for remote cache to be utilized) or the default driver is pointed at (which appears to not utilize the remote cache).

The buildx version I have available to me is github.com/docker/buildx v0.10.4 c513d34, perhaps this feature is in a newer version?

[wellkilo]

With Buildx v0.10.4, the default docker driver cannot use the registry cache exporter/importer in the same way as the docker-container driver. That is the limitation you are observing, not a cache-reference syntax problem.

Use one of these paths:

1. Keep docker-container for registry cache, and export/load the final image:

   docker buildx build \
     --builder mybuilder \
     --cache-from type=registry,ref=REGISTRY/IMAGE:buildcache \
     --cache-to type=registry,ref=REGISTRY/IMAGE:buildcache,mode=max \
     --load \
     -t IMAGE:TAG .
   

2. Upgrade Docker Engine/Buildx and enable the containerd image store. Current Docker documentation says the default docker driver supports cache backends such as inline, local, registry, and gha only when the containerd image store is enabled.

3. Push instead of loading when possible; --push avoids transferring the completed image back into the classic local image store.

Also note that --cache-from imports an existing cache but does not update it. Add the matching --cache-to on the build that should populate/refesh the registry cache.

The current Buildx docs list cache-from/cache-to as external cache sources/destinations, but driver support depends on the backing BuildKit/image-store configuration: Build cache options.