services.prometheus.checkConfig

Check configuration with promtool check. The call to promtool is subject to sandboxing by Nix.

If you use credentials stored in external files (password_file, bearer_token_file, etc), they will not be visible to promtool and it will report errors, despite a correct configuration. To resolve this, you may set this option to "syntax-only" in order to only syntax check the Prometheus configuration.