I have about 30 pods (F#/.NET Core + Azure Functions Runtime) running in a 3-node AKS cluster, each of which I am calling every 5 minutes externally (using Application Insights Availability/Web tests).
I am observing that if the pod is not called often (e.g. only 1x/every 5 minutes) then it takes 5000ms+ to call it (usually the call checks dependencies like if db is reachable, if storage blob container is reachable, or event hub). If I call the pod 10-20 times one after the other, I get very fast reponse times below 100ms.
First I thought the shared storage account (AzureWebJobsStorage env var) could be the issue, but then took 1 pod and reassigned it to a dedicated storage account, and after couple of minutes of inactivity again 5000ms+ response time.
Is there any kind of cold start, or automatic shut down of the pods in case they are inactive for a couple of minutes??