Kubernetes limit CPU requests for kube-system in test environment. - kubernetes

Question

I have 6 google nodes with single core and kube-system pods take too much of CPU.
default scylla-2 200m (21%) 500m (53%) 1Gi (38%) 1Gi (38%)
kube-system fluentd-gcp-v2.0.9-p9pvs 100m (10%) 0 (0%) 200Mi (7%) 300Mi (11%)
kube-system heapster-v1.4.3-dcd99c9f8-n6wb2 138m (14%) 138m (14%) 301856Ki (11%) 301856Ki (11%)
kube-system kube-dns-778977457c-gctgs 260m (27%) 0 (0%) 110Mi (4%) 170Mi (6%)
kube-system kube-dns-autoscaler-7db47cb9b7-l9jhv 20m (2%) 0 (0%) 10Mi (0%) 0 (0%)
kube-system kube-proxy-gke-scylla-default-pool-f500679a-7dhh 100m (10%) 0 (0%) 0 (0%) 0 (0%)
kube-system kubernetes-dashboard-6bb875b5bc-n4xsm 100m (10%) 100m (10%) 100Mi (3%) 300Mi (11%)
kube-system l7-default-backend-6497bcdb4d-cncr4 10m (1%) 10m (1%) 20Mi (0%) 20Mi (0%)
kube-system tiller-deploy-dccdb6fd9-7hd2s 0 (0%) 0 (0%) 0 (0%) 0 (0%)
Is there easy way to lower CPU request/limit for all kube-system pods in 10 times?
I understand memory is needed to function properly but CPU could be lowered without any major issue in dev environment. What happens if DNS would work 10 times slower? 27% of node for single system dns pod is too much.

Answer 1

As peer the documentation To specify a CPU request for a Container, include the resources:requests field in the Container’s resource manifest. To specify a CPU limit, include resources:limits see exemple below:
apiVersion: v1
kind: Pod
metadata:
name: cpu-demo
namespace: cpu-example
spec:
containers:
- name: cpu-demo-ctr
image: vish/stress
resources:
limits:
cpu: "1"
requests:
cpu: "0.5"
args:
- -cpus
- "2"
One cpu, in GCP Kubernetes, is equivalent to: 1 GCP Core.
the CPU limit for a Pod is the sum of the CPU limits for all the Containers in the Pod.
Pod scheduling is based on requests. A Pod is scheduled to run on a Node only if the Node has enough CPU resources available to satisfy the Pod’s CPU request.

Answer 2

You can create a default cpu-request-limit manifest and apply it to the kube-system namespace:
Now if a Container is created in the kube-system namespace, and the Container does not specify its own values for CPU request and CPU limit, the Container is given a default CPU request of 0.5 and a default CPU limit of 1.
https://kubernetes.io/docs/tasks/administer-cluster/manage-resources/cpu-default-namespace/#create-a-limitrange-and-a-pod