Graal: Document what are the requirements for the native image executable

[nfrankel]

It seems to me the executable created by the native image has at least a dependency to a shell. I tried to add the executable to a Docker image FROM scratch and it didn't launch.

Since the native image is a black box, it would be great to explicitly list what requirements are expected - thus we could embed the executable in the smallest Docker image possible.

[nfrankel]

To be a bit more precise, this is the message I have when I add the executable in a FROM scratch container and try to launch it:

OCI runtime create failed: container_linux.go:345: starting container process caused "exec: \"/bin/sh\": stat /bin/sh: no such file or directory": unknown

[greut]

glibc is required.

[nfrankel]

Correct, I have to use an enhanced version of Alpine that contains glibc.

[greut]

native-image --static does the trick too.

[nfrankel]

Might be. But I need a shell and cannot use FROM scratch

[greut]

@nfrankel you don't. I've just used FROM scratch there https://hub.docker.com/layers/greut/hello-java/static/images/sha256-922fe463a2760ad99674b49c3563f0e3a9000b8bfbeb95b5f384a70210d028f2

[nfrankel]

I confirm. Changing from ENTRYPOINT operator to ENTRYPOINT ["operator"] allowed me to use FROM scratch.

Thanks for the help @greut

Closing the issue as it's not Graal VM related.