Prometheus

Wherein I set up some Prometheus metrics gathering from Ceph’s S3 RGW and build a dashboard to show the data. I like metrics. And dashboards. And plots. And one of the things I’ve been missing up to now was data from Ceph’s RadosGateway. That’s the Ceph daemon which provides an S3 (and Swift) compatible API for Ceph clusters. While Rook, the tool I’m using to deploy Ceph in my k8s cluster, already wires up Ceph’s own exporters to be scraped by a Prometheus Operator, that does not include S3 data. My main interest here is the development of bucket sizes over time, so I can see early when something is misconfigured. Up to now, the only indicator I had was the size of the pool backing the RadosGW, which currently stands at 1.42 TB, which makes it the second-largest pool in my cluster. ...

With release 4.4.0 Mastodon introduced a Prometheus exporter. In this post, I will configure it and show the data it provides. With the new release, Mastodon provides metrics from Ruby and Sidekiq. I’ve attached examples for both to this post, see here for Ruby and here for Sidekiq. The information is not actually that interesting, it’s just generic process data. But I did find at least the Sidekiq data worth gathering. It will provide an interesting future look into my usage of Mastodon and perhaps even the activity in the Fediverse (or at least the part I’m connected to) overall. ...

I have been gathering metrics from my DrayTek Vigor 165 modem for a while now, and finally got around to documenting the setup, so now you get to read about it. I’m using the Vigor 165 to connect to the Internet via a Deutsche Telekom 250 Mbit/s VDSL connection. That modem supports SNMP and can provide metrics like the line speed or quality. A couple of years back, I wanted to get that data into my Grafana dashboards. After some searching, I came across the SNMP Exporter. ...

At the time of writing, I have 328 GiB of Prometheus data. When it all started, I had about 250 GiB. I could stop gathering more data whenever I like. 😅 So I’ve got a lot of Prometheus data. Especially since I started the Kubernetes cluster - or rather, since I started scraping it - I had to regularly increase the size of the storage volume for Prometheus. This might very well be due to my 5 year retention. But part of it, as it will turn out later, was because some of the things I was scraping had a 10s scrape interval configured. ...

I had to clean up my Prometheus data, and it got pretty darned close there. When it comes to my metrics, I’m very much a data hoarder. Metrics gathering was what got me into Homelabbing as a hobby, instead of just a means to an end. Telegraf/Influx/Grafana were the first new services on my Homeserver in about five years. And I really do like looking at my dashboards, including looking at past data. My retention period currently is five years. And I’m already pretty sure that when I come up to those five years for the initial data, I will just extend that to 10 years. 😅 ...