prometheus-reloader

A sidecar that reloads Prometheus when config file or rule files change.

Usage

$ prometheus-reloader -config-file testdata/prometheus.yml
I0419 15:30:46.124751   72508 main.go:33] Starting prometheus-reloader 7f0d912 (7f0d912bba736278b2752943bf6287b4658b3490)

After changing prometheus.yml or any of the rule files:

I0419 15:31:06.127397   72508 reloader.go:115] Config change detected, reloading Prometheus at http://127.0.0.1:9090/-/reload

Flags

  -config-file string
    	Prometheus configuration file path (default "/etc/prometheus/prometheus.yml")
  -reload-url string
    	Prometheus reload endpoint (default "http://127.0.0.1:9090/-/reload")
  -watch-interval duration
    	Interval for watching config and rules files for changes (default 10s)

Run prometheus-reloader -h to see the rest of the flags.

Testing with skaffold

1. Run:

skaffold dev --port-forward

2. Open http://127.0.0.1:9090/config in your browser.

3. Make some changes to k8s/configmap.yaml. Skaffold will apply the changes automatically once you save the file.

4. Wait for up to two minutes for Kubernetes to propagate ConfigMap changes.

5. Observe something like:

[prometheus reloader] I0419 14:27:22.139774       1 reloader.go:115] Config change detected, reloading Prometheus at http://127.0.0.1:9090/-/reload
[prometheus] level=info ts=2020-04-19T14:27:22.143Z caller=main.go:788 msg="Loading configuration file" filename=/etc/prometheus/prometheus.yml
[prometheus] level=info ts=2020-04-19T14:27:22.147Z caller=main.go:816 msg="Completed loading of configuration file" filename=/etc/prometheus/prometheus.yml

6. Refresh Prometheus config page in your browser to make sure Prometheus has been reloaded.