Pass arbitrary command line flags to node_exporter

What is missing? A way to pass arbitrary command line flags to node_exporter

Why do we need it? node_exporter has more parameters than those exposed by the variables in this role. An “escape hatch” to pass any flags would be very useful. Something like:

node_exporter_flags: ["--web.telemetry-path=/foo", "--web.max-requests=99"]

In fact, with this variable in place, node_exporter_web_listen_address could be deprecated IMO as it would be adequately covered by the more general node_exporter_flags.

[paulfantom]

I’ll note that node_exporter refuses to start with incorrect/unknown flags, so there is no risk of a mistake going unnoticed.

True, but the current mechanism is more about upgrades than the installation itself. A simple scenario which role wouldn’t be able to prevent with free-form flags option is this:

1. node_exporter is already installed
2. user sets incorrect flags and runs ansible role
3. systemd service is updated and restarted
4. node_exporter is in crash-loop

Above causes downtime. In contrast, failing fast in preflight.yml doesn’t update anything on host and prevents incorrect node configuration.

[paol]

Ah, that’s problem that I hadn’t considered, and also applies to my original idea.

In that case having separate variables for each flag is the only way to go. Consider this enhancement request officially changed 😃