An alert is an event that is considered especially noteworthy and is triggered by a selected event. Alerts are shown with an badge when they appear in a list of events. You can configure the Alert Publisher to send alert notifications by email or by SNMP trap to a trap receiver.
Service instances of type HDFS, MapReduce, and HBase (and their associated roles) can generate alerts if so configured. Alerts can also be configured for the monitoring roles that are a part of the Cloudera Management Service.
The settings to enable or disable specific alerts are found under the Configuration tab for the services to which they pertain.