In monitoring/prometheus/alerts you'll find a set of Prometheus alert rules that
should provide a decent set of default alerts for a Ceph cluster. Just put this
file in a place according to your Prometheus configuration (wherever the rules
configuration stanza points).
Ceph provides a MIB (CEPH-PROMETHEUS-ALERT-MIB.txt) to support sending Prometheus alerts through to an SNMP management platform. The translation from Prometheus alert to SNMP trap requires the Prometheus alert to contain an OID that maps to a definition within the MIB. When making changes to the Prometheus alert rules file, developers should include any necessary changes to the MIB.