I host a static web page with Caddy Server on Google's managed Kubernetes service. I monitor this site with Google Stackdriver.

I deploy my code via a Helm chart. See the source code here (permalink).

I have noticed that the latency will oscillate between about 40 ms and 200 ms every 3 minutes. Almost like clockwork.

As far as I can tell there isn't an obvious correlation between CPU usage and the latency period.

Here is a histogram of CPU usage and latency:

What could be causing this oddly repetitive pattern?