This option can be set to disable installer tools like nixos-rebuild,
nixos-install, and nixos-generate-config (as well as more). This is
nice when a system is not expected to be rebuild or reconfigure itself
such as in a stateless PXE setup, as well as other embedded scenarios.
Note, that the system can still be updated, but it must either get
nixos-rebuild from another source, or, for embedded systems, be
upgraded by another machine like:
nix copy "$system" --to "ssh://root@<host>" && ssh "root@<host>"
"nix-env -p /nix/var/nix/profiles/system --set $system && $system/bin/switch-to-configuration switch".
Along with other options, this allows removing Perl from a closure.
For example:
{
boot.enableContainers = false;
environment.defaultPackages = [];
system.disableInstallerTools = true;
}
should not include Perl.