Alerting is a way to get notified for any event that is important to us. We can configure the alert if any field value crosses the threshold value, which we can set as per the requirements. In Kibana, we can notify using Watcher when the given condition is met. We can set any condition, such as when a filed value crosses a certain threshold value, or if there is any data anomaly in the data, or if we are receiving a certain field in our data.
Let's say these are the events that are critical to us, and we should know whenever they occur. For these situations, we can configure the alerts in Kibana so that we can get a timely notification. In Kibana UI, we can configure the watch for any such condition that is generated by the Elasticsearch query in the background to keep checking the data..
When the configured condition is met, Elasticsearch triggers the alerting system...