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Experimntal container image minimizer. Usesldd and can possibly usestrace in the future to detect the files needed by a binary. It minimizesthe image size because it copies only files needed into a tar which than canbeADDed to for examplebusybox:uclibc image or from scratch.

• Python 2.7 or Python 3+
• ldd -ldd(1)

There are two main use cases.

• building smaller images from other base images
• building images from local environment

Using the offical node 6 image

$ docker run -ti -v $(pwd):/usr/src/app node:6 bash

Inside the node:6 container install your app

> cd /usr/src/app> npm install> ./ocidiet.py -t myapp.tar -b `which node` -e /etc/nsswitch.conf \  /etc/resolv.conf myapp/node_modules myapp/package.json myapp/index.js> exit

and finally on the host build you final app image

# docker build -t myapp .

using the followingDockerfile:

FROM busybox:uclibcADD myapp.tar /ENTRYPOINT ["/usr/local/bin/node"]CMD ["/usr/src/app/myapp/index.js"]

Now you have a node image which has roughly 37 MB + size of your app.

Another option usefull for quick shipping and sharing is to use it forcreating images based on local dev environment. Usefull for compiledC/C++ projects.

Taking the hello world example

#include<stdio.h>intmain(void) {printf("Hello World\n");return0;}

and compiling it withgcc hello.c -o hello we now have an app whichneeds at least libc. If we install it to let's say/usr/local/bin wecan create a container image by first creating the tar

$ ./ocidiet.py -t hello.tar -b /usr/local/bin/hello

and then using the following Dockerfile

FROM busybox:uclibcADD hello.tar /ENTRYPOINT ["/usr/local/bin/hello"]

building the final image.

$ docker build -t hello.

which contains really just thebusybox:uclibc files and thehellobinary and correct version oflibc.

If you don't need the busybox to poke around the running containerjust build it from scratch.

FROM scratchADD hello.tar /ENTRYPOINT ["/usr/local/bin/hello"]

and save around 1.2 MB.