Having a network transmit metric e.g. node_network_transmit_bytes_total from nodeexporter I'd like to get a difference between the transmit rate of an interface (enp3s0 in my case) and a sum of all bridge interface transmit rates.
I have something like this:
irate(node_network_transmit_bytes_total{device="enp3s0"}[1m]) - irate(node_network_transmit_bytes_total{device=~"br.*"}[1m])
but this gives me no datapoints.
EDIT
I've tried what Prometheus/PromQL subtract two gauge metrics suggests but my case is a bit different because on the right hand side I have more than 1 series.
So this:
node_network_transmit_bytes_total{device="enp3s0"} - ignoring(device) node_network_transmit_bytes_total{device=~"br.*"}
yields:
Error executing query: found duplicate series for the match group {instance="192.168.X.Z:9100", job="nodeexporter"} on the right hand-side of the operation: [{name="node_network_transmit_bytes_total", device="br-XXXX", instance="192.168.X.Z:9100", job="nodeexporter"}, {name="node_network_transmit_bytes_total", device="br-5d6dce95c2b0", instance="192.168.X.Z:9100", job="nodeexporter"}];many-to-many matching not allowed: matching labels must be unique on one side
I've tried using sum():
node_network_transmit_bytes_total{device="enp3s0"} - ignoring(device) sum(node_network_transmit_bytes_total{device=~"br.*"})
but that yields no results again.
EDIT2
I've managed to figure out how to get a difference by
sum(node_network_transmit_bytes_total{device="enp3s0"}) by (instance) - sum (node_network_transmit_bytes_total{device=~"br.*"}) by (instance)
but I cannot use irate on it:
irate(sum(node_network_transmit_bytes_total{device="enp3s0"}) by (instance) - sum (node_network_transmit_bytes_total{device=~"br.*"}) by (instance))[5m]
Error executing query: 1:149: parse error: ranges only allowed for vector selectors
