What is a tag?¶
Tags can be thought of as members in a population that you are capturing the metric for. Think of it as a multiple identifying dimensions we support in addition to ‘name’ for a metric.
For example the number of requests/second serviced by an application (metric) could be broken up amongst a group of server instances in a scale-out tier (source) by setting the hostname as the tag in the measurement properties.
Hostname is probably the most common use-case but we make no assumption
about tags except that they distinguishes multiple homogeneous “things”
that all have the same metric, so instead of “hostname” you could use
sensor_id if you wanted.