Switching Between Prometheus Servers in Grafana Using Data Source Variables

Variables in Grafana (previously known as templates) allow parameterisation of a dashboard via a drop-down menu. Often this is used to switch between machines or services, so that you can have per-machine dashboards without needing to create a dashboard every time a new machine appears. They’re also stored in URL parameters, so could be linked from alert notifications or wiki pages.

Source: robustperception.io