Notification on systemd service failures

Development
10

monitoring software is the answer, of course, but to directly answer your question is to use the systemd top level overrides feature like so:

{ config, lib, pkgs, ... }: {
  systemd.packages = [
    (pkgs.runCommandNoCC "on-failure.conf" {
      preferLocalBuild = true;
      allowSubstitutes = false;
    } ''
      mkdir -p $out/etc/systemd/system/service.d/
      echo "[Service]\nOnFailure=email@%n.service" > $out/etc/systemd/system/service.d/on-failure.conf
    '')
  ];
}

untested, so please ping back if this is incorrect and we can edit

reference on discourse: How to use toplevel-overrides for systemd - #4 by hmenke