Prometheus that scrapes etcd might also scrape other things, so we should
specifically ask for etcd metrics, especially when dealing with generic
metrics like `process_resident_memory_bytes`.
This fixes failed RPC rate query, where we do not need
subtraction because we already query by the status code.
Also adds grpc_method to make it more specific. Most of the
time, the failure recovers within 10-second, which is our
Prometheus scrap interval, so 'rate' query might not cover
that time window, showing as 0s, but still shows up in the graph.
Signed-off-by: Gyu-Ho Lee <gyuhox@gmail.com>
paulfantom