use ENTRYPOINT in build to fake uname

[grooverdan]

suggestion to your script:

~/docker-32bit-ubuntu$ cat ubuntu.tgz | ./docker import --message "Build with https://github.com/docker-32bit/ubuntu" --change 'ENTRYPOINT ["/usr/bin/linux32","sh","-c"]'  -   32bit/ubuntu:xenial
sha256:acac9916eca1fad229ed19f98861ee8738267e39593d19cd481b59f5da67fd27

~/docker-32bit-ubuntu$ docker run -ti 32bit/ubuntu:xenial 'uname -a'
Linux 60efb58996e4 4.4.0-62-generic #83-Ubuntu SMP Wed Jan 18 14:10:15 UTC 2017 i686 i686 i686 GNU/Linux

requires newer docker version after moby/moby/issues/27789

tested with:

./docker --version
Docker version 17.04.0-dev, build 7fb83eb

[dashohoxha]

I have taken the first part of your suggestion, adding a message to the image.

For the second part, I think that it makes no sense to run a 32bit container in a 64bit host. These 32bit images are meant to be run on a 32bit host.

If somebody is developing or testing on a 64 bit machine, they should consider setting the entrypoint with docker run --entrypoint, or working on a 32bit virtual machine (for example with VirtualBox), etc.

[grooverdan]

it occurred to me you may be asking why I'm doing this. I'm doing using a 32bit docker container as a CI build/test environment for a software build. So it makes sense to me :-). Thanks for the scripts.