用节点亲和性把 Pod 分配到节点

当前集群信息：

root@k8s-master:~# kubectl get node -o wide
NAME         STATUS   ROLES                  AGE    VERSION   INTERNAL-IP       EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION       CONTAINER-RUNTIME
k8s-master   Ready    control-plane,master   683d   v1.22.0   192.168.123.150   <none>        Ubuntu 18.04.5 LTS   4.15.0-213-generic   docker://20.10.0
k8s-node1    Ready    <none>                 683d   v1.22.0   192.168.123.151   <none>        Ubuntu 18.04.5 LTS   4.15.0-213-generic   docker://20.10.0
k8s-node2    Ready    <none>                 683d   v1.22.0   192.168.123.152   <none>        Ubuntu 18.04.5 LTS   4.15.0-213-generic   docker://20.10.0

给节点添加标签

• 列出集群节点及标签

  root@k8s-master:~# kubectl get node --show-labels
  NAME         STATUS   ROLES                  AGE    VERSION   LABELS
  k8s-master   Ready    control-plane,master   683d   v1.22.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-master,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=,node.kubernetes.io/exclude-from-external-load-balancers=
  k8s-node1    Ready    <none>                 683d   v1.22.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disk=ssd,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-node1,kubernetes.io/os=linux
  k8s-node2    Ready    <none>                 683d   v1.22.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disk=ssd,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-node2,kubernetes.io/os=linux
  
  

• 选择一个节点，给它添加标签（这里我选择node1节点):

  root@k8s-master:~# kubectl label nodes k8s-node1 nodetype=dev
  node/k8s-node1 labeled
  root@k8s-master:~# kubectl get node k8s-node1 --show-labels
  NAME        STATUS   ROLES    AGE    VERSION   LABELS
  k8s-node1   Ready    <none>   683d   v1.22.0   beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disk=ssd,kubernetes.io/arch=amd64,kubernetes.io/hostname=k8s-node1,kubernetes.io/os=linux,nodetype=dev
  
  

  这里给node1打上nodetype=dev标签

依据强制的节点亲和性调度 Pod

下面清单描述了一个 Pod，它有一个节点亲和性配置 requiredDuringSchedulingIgnoredDuringExecution，nodetype=dev。 这意味着 pod 只会被调度到具有 nodetype=dev 标签的节点上。

apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: nodetype
            operator: In
            values:
            - dev           
  containers:
  - name: nginx
    image: nginx
    imagePullPolicy: IfNotPresent

通过此yml文件执行,发现刚刚创建的Pod在node1节点执行

root@k8s-master:~# kubectl get pod -o wide | grep k8s-node1
nginx                                     1/1     Running   0                77s     10.244.36.68     k8s-node1   <none>           <none>

使用首选的节点亲和性调度 Pod

本清单描述了一个 Pod，它有一个节点亲和性设置 preferredDuringSchedulingIgnoredDuringExecution，nodetype=dev。 这意味着 Pod 将首选具有 nodetype=dev 标签的节点。

apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  affinity:
    nodeAffinity:
      preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 1
        preference:
          matchExpressions:
          - key: disktype
            operator: In
            values:
            - ssd          
  containers:
  - name: nginx
    image: nginx
    imagePullPolicy: IfNotPresent