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 created
    • service - the service name that emitted the alert
    • host - the host name that emitted the alert
    • severity - severity of the alert e.g. anomaly, component-failure, service-failure etc.
    • description - a description of the alert
    • data - if there was an exception then a JSON object with fields exceptionType, exceptionMessage and exceptionStackTrace