The historical metrics view displays all Grey Matter metrics collected for this service. These metrics are automatically collected by the Sidecar deployed with each service, and aggregated mesh-wide by an internal Prometheus server. The views here present the Grey Matter metrics collected by the metrics, but all Envoy metrics are collected as well.
The summary view shows some of the most important metrics collected. Here are things like uptime, service-level latencies, route-level usage, host performance, request and error rates.
The routes view focuses on the route level performance rather than the service as a whole.
The Instances view shows the number of individual instances running for the given service. Each line shows a unique ID for each instance, as well as the time the service has been up. Clicking on the Instance ID will drop you down into the real-time metrics view.