Kubernetes高级调度：节点亲和性NodeAffinity

关键词:

① requiredDuringSchedulingIgnoredDuringExecution：表示强匹配，必须要满足

② preferredDuringSchedulingIgnoredDuringExecution：表示弱匹配，尽可能满足，但不保证

官方示例：

apiVersion: v1
kind: Pod
metadata:
  name: with-node-affinity
spec:
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:  ##必须满足下面匹配规则
        nodeSelectorTerms:
        - matchExpressions:
          - key: env
            operator: In  ##逻辑运算符支持：In,NotIn,Exists,DoesNotExist,Gt,Lt
            values:
            - test
            - dev
      preferredDuringSchedulingIgnoredDuringExecution: ##尽可能满足，但不保证
      - weight: 1
        preference:
          matchExpressions:
          - key: project
            operator: In
            values:
            - aminglinux
  containers:
  - name: with-node-affinity
    image: redis:6.0.6

说明：

匹配逻辑：

① 同时指定Node Selector和Node Affinity，两者必须同时满足；

② Node Affinity中指定多组nodeSelectorTerms，只需要一组满足就可以；

③ 当在nodeSelectorTerms中包含多组matchExpressions，必须全部满足才可以；

演示示例：

1、定义pod的yaml

$ cat > nodeAffinity.yaml << EOF
apiVersion: v1
kind: Pod
metadata:
  name: node-affinity
spec:
  containers:
    - name: my-container
      image: nginx:1.21.6
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
          - matchExpressions:
              - key: special-node
                operator: Exists
EOF

2、给k8s-master02节点定义标签

$ k label nodes k8s-master02 special-node=true

3、应用YAML

$ k apply -f nodeAffinity.yaml

4、检查Pod所在node，符合节点亲和性

$ k get po -o wide | grep node-affinity

node-affinity                   1/1     Running   0              4s     172.25.92.79     k8s-master02   <none>           <none>

5、恢复

$ k delete  -f nodeAffinity.yaml

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