At one point in my configuration I had:
boot.kernel.sysctl = {
# https://unix.stackexchange.com/questions/13019/description-of-kernel-printk-values
"kernel.printk" = "4 4 1 7";
};
which triggered:
error: The unique option `boot.kernel.sysctl.kernel.printk' is defined multiple times, in `/home/teto/dotfiles/nixpkgs/mptcp-unstable.nix' and `/home/teto/nixpkgs/nixos/modules/system/boot/kernel.nix'.
(use ‘--show-trace’ to show detailed location information)
Traceback (most recent call last):
File "/home/teto/nixops/scripts/nixops", line 984, in <module>
args.op()
File "/home/teto/nixops/scripts/nixops", line 406, in op_deploy
max_concurrent_activate=args.max_concurrent_activate)
File "/home/teto/nixops/nixops/deployment.py", line 1045, in deploy
self.run_with_notify('deploy', lambda: self._deploy(**kwargs))
File "/home/teto/nixops/nixops/deployment.py", line 1034, in run_with_notify
f()
File "/home/teto/nixops/nixops/deployment.py", line 1045, in <lambda>
self.run_with_notify('deploy', lambda: self._deploy(**kwargs))
File "/home/teto/nixops/nixops/deployment.py", line 985, in _deploy
self.configs_path = self.build_configs(dry_run=dry_run, repair=repair, include=include, exclude=exclude)
File "/home/teto/nixops/nixops/deployment.py", line 653, in build_configs
raise Exception("unable to build all machine configurations")
Exception: unable to build all machine configurations
This simple addition allows to override it.