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Static and Mostly Static Images

Native Image can create static native images and mostly static native images.

Static Images​

Static native images are statically linked binaries without additional library dependencies. These images can run on slim or distroless container images. They are created by statically linking against a libc implementation.

--libc specifies the libc implementation to use when building static images.

ValuesDescription
glibcThe GNU C Library
muslmusl libc
bionicbionic
Create a static image
native-image --static --libc=glibc Main

Mostly Static Images​

Mostly static native images statically link everything except libc. This only works for glibc.

Create a mostly static image
native-image -H:+StaticExecutableWithDynamicLibC Main

Container Image​

The code below shows the Dockerfile to build container images for a static image and a mostly static image.

  • The container image for the static image uses the base image scratch. The result container image is only 16MB.
  • The container image for the mostly static image requires a base image that includes glibc. The size of result container image is much larger.
FROM ghcr.io/graalvm/graalvm-ce:java17-21.3 AS builder

RUN gu install native-image

RUN mkdir /build && mkdir /build/source && mkdir /build/target

WORKDIR /build

COPY Main.java ./source

RUN javac ./source/Main.java -d ./target

RUN native-image -cp ./target --install-exit-handlers --static --libc=glibc -H:Name=helloworld Main

#############

FROM scratch

WORKDIR /

COPY --from=builder /build/helloworld /helloworld

ENTRYPOINT ["/helloworld"]

If a base image of Linux distribution has to be used for other reasons, a mostly static image is a better choice. Otherwise, a static image with scratch base image can save a lot of space.