Pod Priority And Preemption

Pod Priority는 다른 Pod에 비해 Pod의 중요도를 적용하는데 사용된다. 이 섹션에서는 두 개를 만들고 PriorityClass Pod의 상호 작용을 확인 한다.

 

ㅁ PriorityClass 만들기

cat <<EoF > ~/environment/resource-management/high-priority-class.yml
apiVersion: scheduling.k8s.io/v1
kind: PriorityClass
metadata:
  name: high-priority
value: 100
globalDefault: false
description: "High-priority Pods"
EoF

kubectl apply -f ~/environment/resource-management/high-priority-class.yml


cat <<EoF > ~/environment/resource-management/low-priority-class.yml
apiVersion: scheduling.k8s.io/v1
kind: PriorityClass
metadata:
  name: low-priority
value: 50
globalDefault: false
description: "Low-priority Pods"
EoF

kubectl apply -f ~/environment/resource-management/low-priority-class.yml

 

PriorityClass가 없이 생성된 Pods는 0이다. Global PriorityClass가 할당될 수 있다 추가적인 정보를 보려면 여기를 클릭한다.

 

ㅁ Deploy low-priority Pods

 

cat <<EoF > ~/environment/resource-management/low-priority-deployment.yml
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: nginx-deployment
  name: nginx-deployment
spec:
  replicas: 50
  selector:
    matchLabels:
      app: nginx-deployment
  template:
    metadata:
      labels:
        app: nginx-deployment
    spec:
      priorityClassName: "low-priority"      
      containers:            
       - image: nginx
         name: nginx-deployment
         resources:
           limits:
              memory: 1G  
EoF
kubectl apply -f ~/environment/resource-management/low-priority-deployment.yml

 

사용 가능한 Pod가 Deployment 수를 중심으로 안정화 될때까지에서 사용 가능한 Pod 수를 확인한다. 노드가 포드로 완전히 채워졌는지 확인하고 안정화 되는데 최대 2분이 소요될 수 있다.

 

kubectl get deployment nginx-deployment --watch

 

ㅁ Deploy High Priority Pod

 

cat <<EoF > ~/environment/resource-management/high-priority-deployment.yml
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: high-nginx-deployment
  name: high-nginx-deployment
spec:
  replicas: 5
  selector:
    matchLabels:
      app: high-nginx-deployment
  template:
    metadata:
      labels:
        app: high-nginx-deployment
    spec:
      priorityClassName: "high-priority"      
      containers:            
       - image: nginx
         name: high-nginx-deployment
         resources:
           limits:
              memory: 1G
EoF
kubectl apply -f ~/environment/resource-management/high-priority-deployment.yml

 

수행해 보면 high-priority-deployment가 수행되면서 기존 low-priority로 만들어진 pod가 삭제됨을 볼 수 있다.