What is the simplest way to find out the Availability of a K8s service over a period of time, lets say 24h. Should I target a pod or find a way to calculate service reachability
1 Answers
I'd recommend to not approach it from a binary (is it up or down) but from a "how long does it take to serve requests" perspective. In other words, phrase your availability in terms of SLOs. You can get a very nice automatically generated SLO-based alter rules from PromTools. One concrete example rule from there, showing the PromQL part:
1 - (
sum(rate(http_request_duration_seconds_bucket{job="prometheus",le="0.10000000000000001",code!~"5.."}[30m]))
/
sum(rate(http_request_duration_seconds_count{job="prometheus"}[30m]))
)
Above captures the ratio of how long it took the service to serve non-500 (non-server errors, that is, assumed good responses) in less than 100ms to overall responses over the last 30 min with http_request_duration_seconds being the histogram, capturing the distribution of the requests of your service.
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