[Kubernetes] 쿠버네티스 NodeAffinity 실습

실습1)

blue pod는 nginx 이미지로 배포하였으며, 각 노드에 pod가 스케줄링되어 있는 상태입니다.

p.s, node01에는 lable color=blue로 설정되어 있습니다.

controlplane ~ ➜  kubectl get pod -o wide
NAME                    READY   STATUS    RESTARTS   AGE   IP           NODE           NOMINATED NODE   READINESS GATES
blue-7698dfcb9f-7z9dq   1/1     Running   0          19s   10.244.1.3   node01         <none>           <none>
blue-7698dfcb9f-rtg9j   1/1     Running   0          19s   10.244.1.2   node01         <none>           <none>
blue-7698dfcb9f-s8qns   1/1     Running   0          19s   10.244.0.4   controlplane   <none>           <none>

 

 

여기서, Pod를 node01에만 배치하려면 deployment에 노드 affinity를 설정하는 실습을 해보겠습니다.

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: blue
  name: blue
  namespace: default
spec:
  replicas: 3
  selector:
    matchLabels:
      app: blue
  template:
    metadata:
      labels:
        app: blue
    spec:
      containers:
      - image: nginx
        name: nginx
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: color
                operator: In
                values:
                - blue

 

출력 결과:

모든 pod들이 node01에 배치되어 있는 것을 확인할 수 있습니다.

controlplane ~ ➜  kubectl get pod -o wide
NAME                    READY   STATUS    RESTARTS   AGE   IP           NODE     NOMINATED NODE   READINESS GATES
blue-7cf59b987f-cwbl9   1/1     Running   0          65s   10.244.1.6   node01   <none>           <none>
blue-7cf59b987f-kscgz   1/1     Running   0          65s   10.244.1.4   node01   <none>           <none>
blue-7cf59b987f-nb2j4   1/1     Running   0          65s   10.244.1.5   node01   <none>           <none>

 

 

실습2) 

nginx 이미지와 2개의 replica로 red라는 이름의 새 배포를 생성하고 control-plane 노드에만 배치되는지 확인합니다.
컨트롤 플레인 노드에 이미 설정된 라벨 키(node-role.kubernetes.io/control-plane)를 사용하였습니다.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: red
spec:
  replicas: 2
  selector:
    matchLabels:
      run: nginx
  template:
    metadata:
      labels:
        run: nginx
    spec:
      containers:
      - image: nginx
        imagePullPolicy: Always
        name: nginx
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: node-role.kubernetes.io/control-plane
                operator: Exists

 

출력 결과:

controlplane ~ ➜  kubectl get pod -o wide
NAME                    READY   STATUS    RESTARTS   AGE   IP           NODE           NOMINATED NODE   READINESS GATES
blue-7cf59b987f-cwbl9   1/1     Running   0          10m   10.244.1.6   node01         <none>           <none>
blue-7cf59b987f-kscgz   1/1     Running   0          10m   10.244.1.4   node01         <none>           <none>
blue-7cf59b987f-nb2j4   1/1     Running   0          10m   10.244.1.5   node01         <none>           <none>
red-6c897b6676-rwb44    1/1     Running   0          9s    10.244.0.7   controlplane   <none>           <none>
red-6c897b6676-vlbgp    1/1     Running   0          9s    10.244.0.6   controlplane   <none>           <none>