Druid generates alerts on getting into unexpected situations.
Alerts are emitted as JSON objects to a runtime log file or over HTTP (to a service such as Apache Kafka). Alert emission is disabled by default.
All Druid alerts share a common set of fields:
timestamp - the time the alert was createdservice - the service name that emitted the alerthost - the host name that emitted the alertseverity - severity of the alert e.g. anomaly, component-failure, service-failure etc.description - a description of the alertdata - if there was an exception then a JSON object with fields exceptionType, exceptionMessage and exceptionStackTrace