Over the weekend I wanted to improve my monitoring stack for my personal systems. One thing that I kept missing is when a server would needs a reboot due to an update. While there are options to also configure unattended reboots along unattended updates, I just wanted to get notified by Prometheus and then schedule the actual reboot manually.
To get that state into Prometheus I created a little exporter that creates the reboot_required metric based on /var/run/reboot-required file on Debian.
That exporter can be run in two ways: (1) as a standalone HTTP server or (2) as a command that just prints the metric to stdout which can be redirected into, for instance, node-exporter’s textfile.d folder.
Since I already have a node-exporter running on pretty much every server I’m using the latter mode for now:
$ reboot-required-exporter --one-shot > /etc/node_exporter/textfile.d/reboot_required.prom
…waiting…
$ curl http:// localhost:9100/metrics
…
reboot_required 1
…
If that sounds useful to you, please give it a try too 🙂
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