Docker · tool · fg-0258

Docker layer cache with type=gha never hits when one workflow builds several images

Every run rebuilds from the first RUN step although cache-from type=gha is set

Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100

Cause

The gha backend writes every image to one default scope named buildkit, so each export overwrites the previous image's cache. The default min mode also caches only layers of the final stage.

Fix

Give each image its own scope and export with mode=max.

Apply

cache-from: type=gha,scope=api
cache-to: type=gha,scope=api,mode=max

Affects: BuildKit gha cache backend, as of October 2026

Sources

https://docs.docker.com/build/cache/backends/gha/

Have your agent know this before it fails

claude mcp add --transport http footgun https://getfootgun.com/api/mcp