[Nix-dev] custom liveCD image

[Sergey Mironov]

Hi. I want to build a liveCD (minimal_iso) image containing a custom
application. User should be able to launch this application directly
from the liveCD shell.  I've added

  environment.systemPackages = [
    myapp
  ];

to the ..../iso-image.nix in order to it, and noticed that NixOS
builds the app two times! I assume, nixos needs different versions of
myapp for different stages or something like this. Unfortunately, only
one build of myapp is successful. The second build yields mysterious
application-specific error, and I can't reproduce it locally (maybe
the error somehow connected with linux.dev dependency of myapp since
myapp needs Intel's dpdk library which builds some custom kernel
modules). I'd like to avoid the debugging by disabling all builds of
myapp except the final one.

Could you please explain the situation and give me and advice on how
to include the one and only copy of myapp to the liveCD's /nix/store?

Thanks in advance,
Sergey