Source Variance operates identically to the Offset alerts.
Source Variance Alerts:
Source variance alerts provide a simple and effective alert. Configured to one graph with the visualisation restricted to the top 5 offsets (largest variance between UTC sources).
The Grafana server itself, however, is querying all of the hosts, we only visualise the top 5 so that we can maintain the performance of the front end. This alert will automatically trigger an alert when a threshold has been reached. The example above has a threshold set to 1 millisecond, this is also represented by the red line which cuts across the graph.
Although it is unlikely you ever need to visit the alerts pages as the various notification channels will make you aware, they are available if you want to check the configured thresholds or modify them.