kubernetes - Alicloud node memory Requested/Limited/Used

Question

We have a test cluster of 3 nodes on Alicloud

We haven't set any memory limits, per namespace or per pod

However, when looking at the nodes in the alicloud console, we see a Requested/Limited/Used set for the memory. The pods are running out of memory when the Used is over the Limited threshold

Does anyone know where this limit comes from? It seems to be different for each one of our node, so it creates an arbitrary limit per pod?

question from:https://stackoverflow.com/questions/65842348/alicloud-node-memory-requested-limited-used

Answer 1

To be honest I cant find any relevant information where are your current default limits come from.. but anyway you should solve your issue somehow.

I can suggest you manually set required limits to avoid OOMs in future. What you will need to do - is to calculate approximate resource usage and correctly apply limits

This can help:

Kubernetes: Assign Memory Resources and Limits to Containers, especially this part

LimitRange for Memory

Kubernetes administrators can define RAM limits for their nodes.

These limits are enforced at higher priority over how much RAM your Pod declares and wants to use.

Let's define our first LimitRange : 25Mi RAM as min, 200Mi as max.

nano myRAM-LimitRange.yaml

apiVersion: v1
kind: LimitRange
metadata:
  name: my-ram-limit
spec:
  limits:
  - max:
      memory: 200Mi
    min:
      memory: 25Mi