Merge pull request #147504 from NixOS/backport-140743-to-release-21.11

[Backport release-21.11] nixos/acme: add an option for reloading systemd services after renewal

nixos/modules/security/acme.nix

@@ -314,6 +314,9 @@ let
           if [ -e renewed ]; then
             rm renewed
             ${data.postRun}
+            ${optionalString (data.reloadServices != [])
+                "systemctl --no-block try-reload-or-restart ${escapeShellArgs data.reloadServices}"
+            }
           fi
         '');
       };
@@ -474,6 +477,15 @@ let
         description = "Group running the ACME client.";
       };
 
+      reloadServices = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = ''
+          The list of systemd services to call <code>systemctl try-reload-or-restart</code>
+          on.
+        '';
+      };
+
       postRun = mkOption {
         type = types.lines;
         default = "";