Add histogram to keep track of node healthcheck latency
We need a histogram of healthcheck latencies so we can alert when this latency begins to drop. This is a proxy for gitaly node saturation.
This MR adds:
- a
HistogramVec
interface - a function for registering the histogram for node latencies
- inject this histogram into the node manager
- call
Observe
on the histogram whenever we call a node's healthcheck
fixes: #2250 (closed)
Edited by GitLab Release Tools Bot