Just like Graph, alerting is a part of X-Pack Gold and Platinum subscription. Alerting was formerly known as . You can define watchers on cluster events and existing indexes. Watcher can be configured to be executed on schedule. Elasticsearch alerting is very flexible, and the input can be the response to an HTTP request or a query on existing Elasticsearch index. A watch is triggered if the input matches a predefined condition. For example, the input can be the cluster status and condition is "if the cluster status is red". When a condition is triggered, you can define what action has to be taken. An action can be sending an e-mail, indexing a document, sending a slack message, and so on.
For an e-commerce store, let's define a watcher to alert if less than five orders have been placed within the last 30 minutes. The action we will take when the condition...