Prometheus and the NixOS System Version
posted on February 04 2018
Use the Prometheus Node Exporter Textfile collector to help correlate changes in your application’s behavior with NixOS deployments.
First, configure Prometheus’s NodeExporter to enable Textfile collection:
services.prometheus.nodeExporter = {
enable = true;
enabledCollectors = [
"textfile"
];
extraFlags = [
"--collector.textfile.directory=/var/lib/prometheus-node-exporter-text-files"
];
};Second, populate the textfile directory with the current system version on every boot and deployment:
system.activationScripts.node-exporter-system-version = ''
mkdir -pm 0775 /var/lib/prometheus-node-exporter-text-files
(
cd /var/lib/prometheus-node-exporter-text-files
(
echo -n "system_version ";
readlink /nix/var/nix/profiles/system | cut -d- -f2
) > system-version.prom.next
mv system-version.prom.next system-version.prom
)
'';Then, configure Grafana to use the system_version as an Annotation with the following query:
changes(system_version[5m])