We stop short of rewriting all playbooks for Prometheus, and instead
add references to the task of adding playbooks for
everything (prometheus-alerts#16) where we found references to
nagios.

howto/drbd.md

@@ -183,6 +183,8 @@ The `ganeti` Puppet module takes care of basic DRBD configuration, by
 installing the right software (`drbd-utils`) and kernel
 modules. Everything else is handled automatically by Ganeti itself.
 
+TODO: this section is out of date since the Icinga replacement, see [tpo/tpa/prometheus-alerts#16](https://gitlab.torproject.org/tpo/tpa/prometheus-alerts/-/issues/16).
+
 There's a Nagios check for the DRBD service that ensures devices are
 synchronized. It will yield an `UNKNOWN` status when no device is
 created, so it's expected that new nodes are flagged until they host