Docker / Images, Dockerfiles & Build Reliability
Explain an unexpected Docker build-cache miss
A changed input, instruction, build argument or prior layer can invalidate reuse. Inspect the actual build definition and context changes.
Environment and inputs: Docker Engine · Compose v2 and Buildx where specified; Linux containers unless noted. Verify daemon context, installed feature support and authorized host or Swarm manager access first.
Start with this check
Confirm the environment and replace sample objects, namespaces, images, paths and hosts with approved targets. Share only relevant, sanitized output. Follow the workload owner’s process for changes.
git diff -- Dockerfile .dockerignoreRead the result
In a source checkout, this shows local changes to two common build inputs. It does not include all context files, CI arguments or remote source revisions.
Resolve and verify
Compare the failed cache boundary with the builder's logs and exact input digest. Reorder stable and changing work only when that preserves reproducibility and security updates.
Before changing production
Do not disable cache everywhere or hide changed inputs by copying artifacts from an unverified previous build.