쿠버네티스 - 라벨 & 셀렉터 실습

K8s-Label.md

• 파드에 라벨(레이블) 설정 후 셀렉터를 통한 확인

  • labels.yaml

    apiVersion: v1
    kind: Pod
    metadata:
      name: myweb1
        labels:
        environment: production
        app: nginx
    spec:
      containers:
      - image: nginx
        name: myweb1
        ports:
        - containerPort: 80
          protocol: TCP
    ---
    apiVersion: v1
    kind: Pod
    metadata:
      name: myweb2
        labels:
        environment: dev
        app: nginx
    spec:
      containers:
      - image: nginx
        name: myweb2
        ports:
        - containerPort: 80
          protocol: TCP

  • 실행 및 확인

    # 파드 생성
    curl -s -O https://raw.githubusercontent.com/gasida/DKOS/main/3/labels.yaml
    kubectl apply -f labels.yaml
    
    root@k8s-m:~# kubectl get pod
    NAME     READY   STATUS    RESTARTS   AGE
    myweb1   1/1     Running   0          2m20s
    myweb2   1/1     Running   0          2m20s
    
    # 파드 라벨 정보 확인
    kubectl get pod --show-labels
    root@k8s-m:~# kubectl get pod --show-labels
    NAME     READY   STATUS    RESTARTS   AGE   LABELS
    myweb1   1/1     Running   0          5s    app=nginx,environment=production
    myweb2   1/1     Running   0          5s    app=nginx,environment=dev
    
    # 셀렉터를 통한 확인
    kubectl get pod -l environment=production
    root@k8s-m:~# kubectl get pod -l environment=production
    NAME     READY   STATUS    RESTARTS   AGE
    myweb1   1/1     Running   0          2m50s
    
    kubectl get pod -l app=nginx
    root@k8s-m:~# kubectl get pod -l app=nginx
    NAME     READY   STATUS    RESTARTS   AGE
    myweb1   1/1     Running   0          2m59s
    myweb2   1/1     Running   0          2m59s
    
    # 셀렉터를 활용하여 특정 파드 삭제
    kubectl delete pod -l environment=production
    root@k8s-m:~# kubectl delete pod -l environment=production
    pod "myweb1" deleted
    
    # 라벨 제거
    root@k8s-m:~# kubectl get pod --show-labels
    NAME     READY   STATUS    RESTARTS   AGE   LABELS
    myweb2   1/1     Running   0          36s   app=nginx,environment=dev
    
    # 라벨의 키 뒤에 -
    root@k8s-m:~# kubectl label pod myweb2 app-
    pod/myweb2 labeled
    
    root@k8s-m:~# kubectl get pod --show-labels
    NAME     READY   STATUS    RESTARTS   AGE   LABELS
    myweb2   1/1     Running   0          95s   environment=dev
    
    # 다음 실습을 위해서 생성된 파드 삭제
    kubectl delete pod --all

• 1노드셀렉터(nodeSelector)** 를 이용한 파드 배포 확인

  • Pod 가 특정 노드에 할당되도록 스케줄링, nodeSelector 라는 property 를 이용

  • 워커노드 1대에 라벨 지정 후 파드가 해당 워커노드에 배포되는지 확인

    # 노드 기본 라벨 정보 확인
    kubectl get node --show-labels
    root@k8s-m:~# kubectl get node --show-labels
    NAME     STATUS   ROLES                  AGE   VERSION   LABELS
    k8s-m    Ready    control-plane,master   98m   v1.21.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-m,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=,node.kubernetes.io/exclude-from-external-load-balancers=
    k8s-w1   Ready    <none>                 96m   v1.21.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-w1,kubernetes.io/os=linux
    k8s-w2   Ready    <none>                 95m   v1.21.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-w2,kubernetes.io/os=linux
    
    # 커맨드로 노드1에 라벨 설정
    kubectl label node k8s-w1 gpu=ndivia
    root@k8s-m:~# kubectl label node k8s-w1 gpu=ndivia
    node/k8s-w1 labeled
    
    root@k8s-m:~# kubectl get node --show-labels
    NAME     STATUS   ROLES                  AGE    VERSION   LABELS
    k8s-m    Ready    control-plane,master   117m   v1.21.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-m,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=,node.kubernetes.io/exclude-from-external-load-balancers=
    k8s-w1   Ready    <none>                 115m   v1.21.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,gpu=ndivia,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-w1,kubernetes.io/os=linux
    k8s-w2   Ready    <none>                 113m   v1.21.1   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-w2,kubernetes.io/os=linux

  • labels-node.yaml

    apiVersion: v1
    kind: Pod
    metadata:
      name: myweb
    spec:
      containers:
      - image: nginx
        name: myweb
        ports:
        - containerPort: 80
          protocol: TCP
      nodeSelector:
        gpu: ndivia

  • 파드 배포 후 확인

    curl -s -O https://raw.githubusercontent.com/gasida/DKOS/main/3/labels-node.yaml
    kubectl apply -f labels-node.yaml
    
    # 파드 배포 노드 확인
    root@k8s-m:~# kubectl get pod -o wide
    NAME    READY   STATUS    RESTARTS   AGE   IP              NODE     NOMINATED NODE   READINESS GATES
    myweb   1/1     Running   0          26s   172.16.228.68   k8s-w1   <none>           <none>
    
    # 파드를 3개 더 생성
    cat labels-node.yaml | sed "s/name: myweb/name: myweb2/g" | kubectl apply -f -
    cat labels-node.yaml | sed "s/name: myweb/name: myweb3/g" | kubectl apply -f -
    cat labels-node.yaml | sed "s/name: myweb/name: myweb4/g" | kubectl apply -f -
    cat labels-node.yaml
    
    # 파드 배포 노드 확인 : 파드가 워커 노드에 분산 배치되지 않는다!
    root@k8s-m:~# kubectl get pod -o wide
    NAME     READY   STATUS    RESTARTS   AGE     IP              NODE     NOMINATED NODE   READINESS GATES
    myweb    1/1     Running   0          3m53s   172.16.228.68   k8s-w1   <none>           <none>
    myweb2   1/1     Running   0          27s     172.16.228.69   k8s-w1   <none>           <none>
    myweb3   1/1     Running   0          13s     172.16.228.70   k8s-w1   <none>           <none>
    myweb4   1/1     Running   0          12s     172.16.228.71   k8s-w1   <none>           <none>
    
    # 다음 실습을 위해서 생성된 파드 삭제
    kubectl delete pod --all