How to get value at a certain point in time in Prometheus?

Question

linux

Good afternoon,
There is a bunch of Prometheus + Grafana
Prometheus collects the node_network_transmit_bytes metric through the node-exporter on the nodes
Task It is
necessary to monitor traffic consumption from the beginning of the month, as well as for an arbitrary period of time.
I see this as subtracting from the last value of node_network_transmit_bytes the value that was at the beginning of the month.
But don't know how to make a request

Answer 1

MB is better through Grafana? Display the metric on the dashboard and set up the legend to display avg. The interval is selected by means of Grafana, let's say this month.
ps Grafana has an excellent dashboard for node exporter on the official website.