Pod Scheduling

nodeName

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: myweb-rs-nn
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      nodeName: node2
      containers:
        - name: myweb
          image: ghcr.io/c1t1d0s7/go-myweb

nodeSelector

노드 레이블
node1

beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/arch=amd64
kubernetes.io/hostname=node1
kubernetes.io/os=linux
node-role.kubernetes.io/control-plane=
node-role.kubernetes.io/master=
node.kubernetes.io/exclude-from-external-load-balancers=

node2

beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/arch=amd64
kubernetes.io/hostname=node2
kubernetes.io/os=linux

node3

beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/arch=amd64
kubernetes.io/hostname=node3
kubernetes.io/os=linux

kubectl label node node1 gpu=highend
kubectl label node node2 gpu=midrange
kubectl label node node3 gpu=lowend

kubectl get nodes -L gpu

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: myweb-rs-ns
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      nodeSelector:
        gpu: lowend
      containers:
        - name: myweb
          image: ghcr.io/c1t1d0s7/go-myweb

Affinity

• affinity
  - pod
  - node
• anti-affinty
  - pod

myweb-a.yaml

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: myweb-a
spec:
  replicas: 2
  selector:
    matchLabels:
      app: a
  template:
    metadata:
      labels:
        app: a
    spec:
      affinity:
        nodeAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
            - weight: 10
              preference:
                matchExpressions:
                  - key: gpu
                    operator: Exists
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                 matchLabels:
                   app: a
              topologyKey: "kubernetes.io/hostname"
      containers:
        - name: myweb
          image: ghcr.io/c1t1d0s7/go-myweb

myweb-b.yaml

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: myweb-b
spec:
  replicas: 2
  selector:
    matchLabels:
      app: b
  template:
    metadata:
      labels:
        app: b
    spec:
      affinity:
        nodeAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
            - weight: 10
              preference:
                matchExpressions:
                  - key: gpu
                    operator: Exists
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                 matchLabels:
                   app: b
              topologyKey: "kubernetes.io/hostname"
        podAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                 matchLabels:
                   app: a
              topologyKey: "kubernetes.io/hostname"
      containers:
        - name: myweb
          image: ghcr.io/c1t1d0s7/go-myweb

Cordon & Drain

Cordon:
스케줄링 금지

kubectl cordon <NODENAME>

스케줄링 허용

kubectl uncordon <NODENAME>

Drain:
Cordon -> 기존 파드를 제거

kubectl drain <NODENAME> --ignore-daemonsets

kubectl uncordn <NODENAME>

Taint & Toleration

Control Plane
Taint: "node-role.kubernetes.io/master:NoSchedule"

Taint: 특정 노드에 역할을 부여
Toleration: Taint 노드에 스케줄링 허용

kubectl taint node node1 node-role.kubernetes.io/master:NoSchedule

      tolerations:
        - key: node-role.kubernetes.io/master
          operator: Exists
          effect: NoSchedule

myweb-a.yaml

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: myweb-a
spec:
  replicas: 3
  selector:
    matchLabels:
      app: a
  template:
    metadata:
      labels:
        app: a
    spec:
      tolerations:
        - key: node-role.kubernetes.io/master
          operator: Exists
          effect: NoSchedule
      affinity:
        nodeAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
            - weight: 10
              preference:
                matchExpressions:
                  - key: gpu
                    operator: Exists
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                 matchLabels:
                   app: a
              topologyKey: "kubernetes.io/hostname"
      containers:
        - name: myweb
          image: ghcr.io/c1t1d0s7/go-myweb

---

kubectl cordon node2

kubectl describe nodes | grep -i taint

kubectl uncordon node2

kubdectl describe nodes | grep -i taint