I'm still getting to grips with PromQL. I wrote this query in an attempt to detect the number of kubernetes pods that existed in the last 24 hours within a given namespace.
My process here was:
increase() to get the range vectors for each pod back into instant vectors. The value will always be 0 as the creation time does not increase.count() to see how many existed in that time frame.count(increase(kube_pod_created{namespace=~".*-airflow"}[1d]))Can anyone that knows prometheus well tell me if this logic follows? Since it isn't a normal database/etc I'm having trouble working out how to validate this query. It "looks" like it probably does the right thing when expanded out to a day though.
The following query should return the number of pods that existed in the last 24 hours:
count(last_over_time(kube_pod_created[24h]))The last_over_time(kube_pod_created[24h]) returns time series for pods that existed in the last 24 hours (see last_over_time() docs). The count() returns the number of such time series, which equals to the number of pods that existed in the last 24 hours.
I'd recommend substituting increase() with count_over_time(), since increase may miss short-living pods with lifetime smaller than 2x scrape interval. The following query should return the total number of pods seen during the last 24 hours:
count(count_over_time(kube_pod_created{namespace=~".*airflow"}[24h]))