Stages can be built in parallel when using BuildKit
build2 are built at the same time
FROM alpine AS build1 RUN touch /opt/binary1 FROM alpine AS build2 RUN touch /opt/binary2 FROM alpine AS final COPY --from=build1 /opt/binary1 /opt/ COPY --from=build2 /opt/binary2 /opt/
Concurrency is determined based on the dependency graph
Stages have a delay
Build sequentially using the legacy build engine:
time docker build .
Build in parallel using BuildKit:
DOCKER_BUILDKIT=1 docker build .
Sequential build will take double the time
Parallel builds reduce the waiting time