Advanced POD CPU and Memory management

LimitRange는 namespace에서 Request와 Limit 사이의 비율을 계산, 저장 또는 적용하는데 사용된다. 이 섹션에서는 컴퓨터 워크로드를 low-usage, high-usage 그리고 unrestricted-usage로 구분한다.

 

먼저 분리된 Namespace를 만든다.

 

mkdir ~/environment/resource-management

kubectl create namespace low-usage
kubectl create namespace high-usage
kubectl create namespace unrestricted-usage

 

ㅁ Create Limit Range

 

low-usage와 high-usage namespace level에 대한 LimitRange spec을 만든다. unrestricted-usage는 어떤 제한도 적용되지 않는다.

 

cat <<EoF > ~/environment/resource-management/low-usage-limit-range.yml
apiVersion: v1
kind: LimitRange
metadata:
  name: low-usage-range
spec:
  limits:
  - max:
      cpu: 1
      memory: 300M 
    min:
      cpu: 0.5
      memory: 100M
    type: Container
EoF

kubectl apply -f ~/environment/resource-management/low-usage-limit-range.yml --namespace low-usage


cat <<EoF > ~/environment/resource-management/high-usage-limit-range.yml
apiVersion: v1
kind: LimitRange
metadata:
  name: high-usage-range
spec:
  limits:
  - max:
      cpu: 2
      memory: 2G 
    min:
      cpu: 1
      memory: 1G
    type: Container
EoF

kubectl apply -f ~/environment/resource-management/high-usage-limit-range.yml --namespace high-usage

 

ㅁ Deploy Pods

 

실패 시도

# Error due to higher memory request than defined in low-usage namespace: wanted 1g memory above max of 300m
kubectl run --namespace low-usage --requests=memory=1G,cpu=0.5 --image  hande007/stress-ng basic-request-pod --restart=Never --  --vm-keep   --vm-bytes 2g --timeout 600s --vm 1 --oomable --verbose 

# Error due to lower cpu request than defined in high-usage namespace: wanted 0.5 below min of 1
kubectl run --namespace high-usage --requests=memory=1G,cpu=0.5 --image  hande007/stress-ng basic-request-pod --restart=Never --  --vm-keep   --vm-bytes 2g --timeout 600s --vm 1 --oomable --verbose 

ㅇ  

 

eksuser:~/environment $ kubectl run --namespace low-usage --requests=memory=1G,cpu=0.5 --image hande007/stress-ng basic-request-pod --restart=Never -- --vm-keep --vm-bytes 2g --timeout 600s --vm 1 --oomable --verbose                                                        
The Pod "basic-request-pod" is invalid: spec.containers[0].resources.requests: Invalid value: "1G": must be less than or equal to memory limit
eksuser:~/environment $ kubectl run --namespace high-usage --requests=memory=1G,cpu=0.5 --image hande007/stress-ng basic-request-pod --restart=Never -- --vm-keep --vm-bytes 2g --timeout 600s --vm 1 --oomable --verbose
Error from server (Forbidden): pods "basic-request-pod" is forbidden: minimum cpu usage per Container is 1, but request is 500m

 

 

성공 시도

kubectl run --namespace low-usage --image  hande007/stress-ng low-usage-pod --restart=Never --  --vm-keep   --vm-bytes 200m --timeout 600s --vm 2 --oomable --verbose 
kubectl run --namespace high-usage  --image  hande007/stress-ng high-usage-pod --restart=Never --  --vm-keep   --vm-bytes 200m --timeout 600s --vm 2 --oomable --verbose 
kubectl run --namespace unrestricted-usage --image  hande007/stress-ng unrestricted-usage-pod --restart=Never --  --vm-keep   --vm-bytes 200m --timeout 600s --vm 2 --oomable --verbose 

 

Pod Limit 검증

eval 'kubectl  -n='{low-usage,high-usage,unrestricted-usage}' get pod -o=custom-columns='Name:spec.containers[*].name','Namespace:metadata.namespace','Limits:spec.containers[*].resources.limits';'

eksuser:~/environment $ eval 'kubectl  -n='{low-usage,high-usage,unrestricted-usage}' get pod -o=custom-columns='Name:spec.containers[*].name','Namespace:metadata.namespace','Limits:spec.containers[*].resources.limits';'
Name            Namespace   Limits
low-usage-pod   low-usage   map[cpu:1 memory:300M]
Name             Namespace    Limits
high-usage-pod   high-usage   map[cpu:2 memory:2G]
Name                     Namespace            Limits
unrestricted-usage-pod   unrestricted-usage   <none>

 

Clean up

kubectl delete namespace low-usage
kubectl delete namespace high-usage
kubectl delete namespace unrestricted-usage