使用 kubectl run 的多节点选择器

Question

我正在使用命令来创建 Pod 并选择节点

kubectl run newpod --image image1 --command run over --overrides='{ "apiVersion": "v1", "spec": { "template": { "spec": { "nodeSelector": { "kubernetes.io/hostname": "one-worker-node" } } } } }'

问题是它运行在一个名为“one-worker-node”的工作节点上。我无法让它在两个或更多工作节点上运行。喜欢

kubectl run newpod --image image1 --command run over --overrides='{ "apiVersion": "v1", "spec": { "template": { "spec": { "nodeSelector": { "kubernetes.io/hostname": "one-worker-node" : "second-worker-node"} } } } }'

Answer 1

您不能使用 来做到这一点nodeSelector，因为您需要使用相同的键传递两个键值。像这样的东西：

kubectl run newpod --image image1 --overrides='{ "apiVersion": "v1", "spec": { "nodeSelector": { "kubernetes.io/hostname": "one-worker-node", "kubernetes.io/hostname": "second-worker-node" } } }'

这相当于：

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
    run: nginx
spec:
  containers:
  - name: nginx
    image: nginx
  nodeSelector:
    kubernetes.io/hostname: one-worker-node
    kubernetes.io/hostname: second-worker-node

如果您要部署此 pod，则只有最后一个标签才会生效，因为 Pod yaml 中的第一个标签将被覆盖。

所以，你会使用nodeAffinity. 这应该可以从命令行运行：

kubectl run newpod --image image1 --overrides='{ "spec": { "affinity": { "nodeAffinity": { "requiredDuringSchedulingIgnoredDuringExecution": { "nodeSelectorTerms": [{ "matchExpressions": [{ "key": "kubernetes.io/hostname",  "operator": "In", "values": [ "one-worker-node", "second-worker-node" ]} ]} ]} } } } }'

这相当于：

apiVersion: v1
kind: Pod
metadata:
  name: newpod
spec:
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: kubernetes.io/hostname
            operator: In
            values:
            - one-worker-node
            - second-worker-node
  containers:
  - name: image1
    image: image1

您可以将所有候选人添加到values. 另外，您可能希望将其作为首选项preferredDuringSchedulingIgnoredDuringExecution，或两者兼而有之；偏好和要求。

概念验证

root@master-1-v1-20:~# kubectl get no
NAME             STATUS   ROLES      AGE   VERSION
master-1-v1-20   Ready    master     43d   v1.20.2
worker-1-v1-20   Ready    worker-1   42d   v1.20.2
worker-2-v1-20   Ready    worker-2   42d   v1.20.2
root@master-1-v1-20:~# grep affinity -A8 affinity.yaml 
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: kubernetes.io/hostname
            operator: In
            values:
            - worker-1-v1-20 
root@master-1-v1-20:~# kubectl create -f affinity.yaml 
pod/newpod created
root@master-1-v1-20:~# kubectl get po newpod -owide
NAME     READY   STATUS    RESTARTS   AGE   IP                NODE             NOMINATED NODE   READINESS GATES
newpod   1/1     Running   0          18s   192.168.127.102   worker-1-v1-20   <none>           <none>

我将名称更改为newpod-2并将其配置为在第二个节点上运行：

root@master-1-v1-20:~# vim affinity.yaml 
root@master-1-v1-20:~# grep affinity -A8 affinity.yaml 
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: kubernetes.io/hostname
            operator: In
            values:
            - worker-2-v1-20 
root@master-1-v1-20:~# kubectl create -f affinity.yaml 
pod/newpod-2 created
root@master-1-v1-20:~# kubectl get po newpod newpod-2 -owide
NAME       READY   STATUS    RESTARTS   AGE     IP                NODE             NOMINATED NODE   READINESS GATES
newpod     1/1     Running   0          4m26s   192.168.127.102   worker-1-v1-20   <none>           <none>
newpod-2   1/1     Running   0          3m25s   192.168.118.172   worker-2-v1-20   <none>           <none>