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Systems Monitoring with Prometheus and Grafana

flightaware.engineering

11–20 of 107 posts

Re: Systems Monitoring with Prometheus and Grafana

#11

Prometheus and Grafana are awesome, use them personally for all my monitoring. However I’m still trying to nail down my high cardinality/highly unique metrics-like data story. What are people using? I’ve heard a combination of Cassandra/BigTable and Spark as a potential solution?

TimescaleDB is a long-term storage option for Prometheus metrics, has no problem with high-cardinality, and now natively supports PromQL (in addition to SQL) [0]

(Disclaimer: I work at Timescale)

[0] https://github.com/timescale/timescale-prometheus

Re: Systems Monitoring with Prometheus and Grafana

#12
What do you all do with the collected metrics over time? Do you store everything forever, drop everything after a couple weeks, or something on between? I've heard of people thinning out old data a bit (?) and storing it long term rather than storing everything. What's the usual thing people do?

Re: Systems Monitoring with Prometheus and Grafana

#13
I have a love/hate relationship with Prometheus. If I had no budget for metrics its likely the thing I would reach for, but I’m dying for someone to open source a ‘next level’ metrics system (something like Monarch or Circonus but free).

But woe betide the team that has to run it as a service. Not that other metrics systems are better but Prometheus can be brutal in that space.

As a ‘squad level’ tool its really good. After that it gets hairy fast.

Re: Systems Monitoring with Prometheus and Grafana

#14
Grafana truly is best in class, but I have strong reservations about Prometheus.

I really want to like it, it’s just so _easy_, publish a little webpage with your metrics and Prometheus takes care of the rest. Lovely.

But I often find that the cardinality of the data is substantially lower than even the defaults of alternatives (influxdb has 1s and even Zabbix has 5s).

Not to mention the lost writes (missing data points) which have no logged explanation.

All of this, however, was in my homelab, which, while unconstrained in resources lacks a lot of the fit and finish of a prod system.

I also take pause with the architecture; it’s not meant to scale. It’s written on the tin so it’s not like I’m picking fault, but when you’re building a dashboard that sucks in data from 25 different Prometheus data sources, it becomes difficult to run functions like SUM(), because the keys may be out of sync causing some really ugly and inaccurate representations of data.

Everything about the design (polling, single database) tells me that it was designed primarily to sit alongside something small. It could never handle the tens of millions of data points per second that I ingest(ed) at my (now previous) job.

But it has a lot of hype, and maybe I’m holding it wrong.

Re: Systems Monitoring with Prometheus and Grafana

#15

Prometheus and Grafana are awesome, use them personally for all my monitoring. However I’m still trying to nail down my high cardinality/highly unique metrics-like data story. What are people using? I’ve heard a combination of Cassandra/BigTable and Spark as a potential solution?

I found this interesting. My plan is to move from Prom to Victoria.

https://medium.com/@valyala/measuring-vertical-scalability-f...

Re: Systems Monitoring with Prometheus and Grafana

#17
post #8

Earlier quoted context omitted.

Prometheus "scales" really well, but it does so via segmentation and federation, rather than increasing the size of an e.g. cluster. Some use cases don't fit to that model, so projects like Cortex and Thanos exist.

not vertically at least. the memory usage for indexing has room for improvement. If I read the pprofs correctly, every scrape interval and every remote write allocates huge amounts of memory which is only cleaned up on garbage collection. You can easily need >64 gb ram for tenthousands of time series, otherwise you oom.

I do 15 million on about 64GB average memory. Have you tried recently?

Re: Systems Monitoring with Prometheus and Grafana

#18
post #8

Earlier quoted context omitted.

Prometheus "scales" really well, but it does so via segmentation and federation, rather than increasing the size of an e.g. cluster. Some use cases don't fit to that model, so projects like Cortex and Thanos exist.

not vertically at least. the memory usage for indexing has room for improvement. If I read the pprofs correctly, every scrape interval and every remote write allocates huge amounts of memory which is only cleaned up on garbage collection. You can easily need >64 gb ram for tenthousands of time series, otherwise you oom.

Biggest single promethueus server I have access to currently uses almost 64GiB of RAM and ingests about 80000 samples per second. Most of scrape intervals is 60s. It is about 5 000 000 time series. Note that we do have more time series - above server is just a horizontal shard, ingesting just one part of total metrics volume there.

Re: Systems Monitoring with Prometheus and Grafana

#19

What do you all do with the collected metrics over time? Do you store everything forever, drop everything after a couple weeks, or something on between? I've heard of people thinning out old data a bit (?) and storing it long term rather than storing everything. What's the usual thing people do?

High fidelity operational metrics have a useful half life measured in days or weeks. Read patterns for longer term use cases are also categorically different. Best architecture is to have a separate system for long term stuff, which treats Prometheus as a data source. Then Prometheus can drop after 14-28d.

Re: Systems Monitoring with Prometheus and Grafana

#20

Prometheus and Grafana are awesome, use them personally for all my monitoring. However I’m still trying to nail down my high cardinality/highly unique metrics-like data story. What are people using? I’ve heard a combination of Cassandra/BigTable and Spark as a potential solution?

I found this interesting. My plan is to move from Prom to Victoria. https://medium.com/@valyala/measuring-vertical-scalability-f...

Woof, good luck. Not a great product.
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