pod亲和性和节点亲和性类似，也非为硬亲和软亲和
● 案例一(硬亲和)

[root@maxiaoke local-k8s-yaml]# kubectl label node centos-7-55 cpu=slow  # 此时三个节点都存在cpu标签，仅centos-7-55为cpu=slow其它为high
[root@maxiaoke local-k8s-yaml]# kubectl get pod -l app=nginx -o wide # 为了效果明显，建nginx-deploy减少为1个副本，当前在cnetos-7-56上
NAME                           READY   STATUS    RESTARTS   AGE   IP            NODE          NOMINATED NODE   READINESS GATES
nginx-deploy-cfbbb7cbd-jb4xz   1/1     Running   0          13m   172.16.5.40   centos-7-56   <none>           <none>

apiVersion: apps/v1
kind: Deployment
metadata:
  name: slb-deploy
spec:
  replicas: 5
  selector:
    matchLabels:
      app: slb
  template:
    metadata:
      labels:
        app: slb
    spec:
      containers:
      - name: slb-demo
        image: linuxmaxiaoke/nginx:v1.0.1
      affinity:
        podAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          # centos-7-54和centos-7-56都满足
          - labelSelector: 
              matchLabels:
                app: nginx
            namespaces: [default]
            topologyKey: cpu

[root@maxiaoke local-k8s-yaml]# kubectl get pod -l app=slb -o wide # centos-7-55不满足 cpu=high，所以不会调度
NAME                         READY   STATUS    RESTARTS   AGE     IP             NODE          NOMINATED NODE   READINESS GATES
slb-deploy-7d9b6c47d-drjls   1/1     Running   0          4m19s   172.16.3.165   centos-7-54   <none>           <none>
slb-deploy-7d9b6c47d-dsw7t   1/1     Running   0          4m19s   172.16.5.43    centos-7-56   <none>           <none>
slb-deploy-7d9b6c47d-fn6k2   1/1     Running   0          4m19s   172.16.5.44    centos-7-56   <none>           <none>
slb-deploy-7d9b6c47d-kw9vh   1/1     Running   0          4m19s   172.16.3.166   centos-7-54   <none>           <none>
slb-deploy-7d9b6c47d-pl6lz   1/1     Running   0          4m19s   172.16.5.45    centos-7-56   <none>           <none>

案例二(软亲和)

[root@maxiaoke local-k8s-yaml]# kubectl label node centos-7-54 cpu=slow --overwrite # 使得仅cnetos-7-56满足cpu=high

apiVersion: apps/v1
kind: Deployment
metadata:
  name: slb-deploy
spec:
  replicas: 5
  selector:
    matchLabels:
      app: slb
  template:
    metadata:
      labels:
        app: slb
    spec:
      containers:
      - name: slb-demo
        image: linuxmaxiaoke/nginx:v1.0.1
      affinity:
        podAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - podAffinityTerm:
              labelSelector: 
                matchLabels:
                  app: nginx
              namespaces: [default]
              topologyKey: cpu
            weight: 10

[root@maxiaoke local-k8s-yaml]# kubectl get pod -l app=slb -o wide # 大部分选择了cnetos-7-56，而不是全部梭哈
NAME                          READY   STATUS    RESTARTS   AGE   IP             NODE          NOMINATED NODE   READINESS GATES
slb-deploy-6b5fc7bd96-78cj4   1/1     Running   0          16s   172.16.5.48    centos-7-56   <none>           <none>
slb-deploy-6b5fc7bd96-clchc   1/1     Running   0          18s   172.16.3.167   centos-7-54   <none>           <none>
slb-deploy-6b5fc7bd96-fxwjf   1/1     Running   0          16s   172.16.5.47    centos-7-56   <none>           <none>
slb-deploy-6b5fc7bd96-ls8zr   1/1     Running   0          18s   172.16.5.46    centos-7-56   <none>           <none>
slb-deploy-6b5fc7bd96-zn9t8   1/1     Running   0          18s   172.16.4.5     centos-7-55   <none>           <none>