Kubernetes（k8s）的排程器 - 排程親和性詳細介紹

節點親和性

pod.spec.nodeAffinity

• preferredDuringSchedulingIgnoredDuringExecution：軟政策
• requiredDuringSchedulingIgnoredDuringExecution：硬政策

requiredDuringSchedulingIgnoredDuringExecution

apiVersion: v1
kind: Pod
metadata:
  name: affinity
  labels:
    app: node-affinity-pod
spec:
  containers:
  - name: with-node-affinity
    image: wangyanglinux/myapp:v1
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: kubernetes.io/hostname
            operator: NotIn
            values:
            - node02
           

preferredDuringSchedulingIgnoredDuringExecution

apiVersion: v1
kind: Pod
metadata:
  name: affinity
  labels:
    app: node-affinity-pod
spec:
  containers:
  - name: with-node-affinity
    image: wangyanglinux/myapp:v1
  affinity:
    nodeAffinity:
      preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 1
        preference:
          matchExpressions:
          - key: kubernetes.io/hostname
            operator: In
            values:
            - node3
           

先硬後軟

apiVersion: v1
kind: Pod
metadata:
  name: affinity
  labels:
    app: node-affinity-pod
spec:
  containers:
  - name: with-node-affinity
    image: hub.atguigu.com/library/myapp:v1
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: kubernetes.io/hostname
            operator: NotIn
            values:
            - k8s-node02
      preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 1
        preference:
          matchExpressions:
          - key: source
            operator: In
            values:
            - qikqiak
           

鍵值運算關系

• In：label 的值在某個清單中
• NotIn：label 的值不在某個清單中
• Gt：label 的值大于某個值
• Lt：label 的值小于某個值
• Exists：某個 label 存在
• DoesNotExist：某個 label 不存在

 Pod  親和性

pod.spec.affinity.podAffinity/podAntiAffinity

• preferredDuringSchedulingIgnoredDuringExecution：軟政策
• requiredDuringSchedulingIgnoredDuringExecution：硬政策

apiVersion: v1
kind: Pod
metadata:
  name: pod-3
  labels:
    app: pod-3
spec:
  containers:
  - name: pod-3
    image: wangyanglinux/myapp:v1
  affinity:
    podAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
      - labelSelector:
          matchExpressions:
          - key: app
            operator: In
            values:
            - pod-1
        topologyKey: kubernetes.io/hostname
    podAntiAffinity:
      preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 1
        podAffinityTerm:
          labelSelector:
            matchExpressions:
            - key: app
              operator: In
              values:
              - pod-2
          topologyKey: kubernetes.io/hostname
           

親和性/反親和性排程政策比較如下：

排程政策比對 标簽	比對 标簽	操作符	拓撲域 支援	排程目标
nodeAffinity	主機	In, NotIn, Exists, DoesNotExist, Gt, Lt	否	指向主機
podAffinity	POD	In, NotIn, Exists, DoesNotExist	是	POD與指定POD同一拓 撲域
podAnitAffinity	POD	In, NotIn, Exists, DoesNotExist	是	POD與指定POD不在同 一拓撲域