Multi Stage Builds

Multi Stage Builds

Separate build and runtime environments

Build environment Runtime environment
Compilers (e.g. javac) Runtime (e.g. java)
Build dependencies Execution dependencies
Build tools (e.g. make) -
Large image Smaller attack surface

Multi Stage Builds

Build in parallel

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/

build1 and build2 are built at the same time

Concurrency is determined based on the dependency graph

Demo: Multi Stage Builds

Compile in parallel using JDK

Combine in final image using JRE


Build in parallel using BuildKit:

docker build --tag hello-demo .

Run default hello:

docker run hello-demo

Run other hello:

docker run hello-demo HelloHeise