Thank you. Brian. I'm worried about the blackbox_exporter is expensive or not.
I also have other jobs, other jobs are with global 30s scrape intervals and 30s evaluation invervals, when I set the special job with scrape interval 2m, will it cause any problem? " If you only want to *check* a value every 1 day for alerting, then it's perfectly fine to have an alerting rule group with a 1 day evaluation interval - even if the underlying metric is collected more frequently. The alerting rule will use the most recent value at evaluation time. " regarding this point, is it possible to set alerting rule group for a special rule or a job? On Friday, August 12, 2022 at 3:40:23 PM UTC+8 Brian Candler wrote: > Perhaps the most import question to ask is: *why* do you only want to > scrape once per day? > > If you're worrying about storage space consumption: don't. Prometheus > uses differential encoding. If you record the same metric repeatedly with > the same value, i.e. the difference between the adjacent values is zero, > then the amount of storage space used is miniscule. Even if it's not the > same value, it's extremely highly compressed. And disk space is cheap. > > If you only want to *check* a value every 1 day for alerting, then it's > perfectly fine to have an alerting rule group with a 1 day evaluation > interval - even if the underlying metric is collected more frequently. The > alerting rule will use the most recent value at evaluation time. > > If you're worried that the exporter itself is expensive to run on each > scrape, then you should do one of the other things that Stuart suggested > (i.e. using textfile collector or push gateway). On the target node use a > cron job to update the metric at whatever interval makes sense - but let > prometheus scrape it as often as it likes. But you should still scrape the > cached value every 1-2 minutes. > > If it's blackbox_exporter that you're talking about, those scrapes are > cheap. So you may as well scrape every 2 minutes. > > If you're worried about transient errors causing spurious alarms, then > adjust your alerting rules (e.g. in the simplest case, add "for: 30m" which > means that you'll only get a notification if the alert has been active for > 30m *continuously*). > > On Friday, 12 August 2022 at 08:31:09 UTC+1 Stuart Clark wrote: > >> On 12/08/2022 08:29, nina guo wrote: >> > So if with push gateway or textfile collector, we need to also to >> > customize our metrics, am I right? >> >> What do you mean? >> >> -- >> Stuart Clark >> >> -- You received this message because you are subscribed to the Google Groups "Prometheus Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to prometheus-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/prometheus-users/0a952d82-c1d7-4ad1-9978-20b84985b698n%40googlegroups.com.
