$ nix-build -A stage-1 /nix/store/ikbsfjx3yxdfj348vifjk9ykryg4bpci-stage-1
stage-1 is a script defined as
config.system.build.bootStage1. It is the content of the initrd.
TODO Describe stage-1.
It prepares the Nix store (at
/mnt/nix/store, which will be at
switch_root is performed).
The final action of stage-1 is to call
/mnt as the new root) to execute stage-2.
In vpsadminos, the stage-1 exists as a script,
stage-1-init.sh (just like
stage-2-init.sh). It contains code testing a possible
nolive flag, and thus the two branches of the
In not-os, the flag is defined at build time so the generated script contains only the desired code. Similarly, the
overlay kernel module is loaded only if necessay. The resulting script is less flexible but I like the idea of generating exactly what we decide.