使用拓扑密钥的反亲和性规则部署失败：kubernetes.io/hostname - 必需值：不能为空

Question

我有一个反关联规则，要求 kubernetes 将来自同一部署的 pod 调度到不同的节点上，我们已经成功使用了很长时间。

affinity:
  podAntiAffinity:
    requiredDuringSchedulingIgnoredDuringExecution:
    - topologyKey: kubernetes.io/hostname
      labelSelector:
        matchExpressions:
        - key: application
          operator: In
          values:
          - {{ $appName }}
        - key: proc  
          operator: In
          values:
          - {{ $procName }}

我正在尝试将我的 pod 关联规则更新为强偏好而不是硬性要求，这样如果部署需要的副本数多于可用节点的数量，我们就不需要扩展我们的集群。

affinity:
  podAntiAffinity:
    preferredDuringSchedulingIgnoredDuringExecution:
    - topologyKey: kubernetes.io/hostname
      weight: 100
      labelSelector:
        matchExpressions:
        - key: application
          operator: In
          values:
          - {{ $appName }}
        - key: proc 
          operator: In
          values:
          - {{ $procName }}

但是，当我尝试应用新规则时，topologyKey 出现意外错误：

Error: Deployment.apps "core--web" is invalid:
[spec.template.spec.affinity.podAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution[0].podAffinityTerm.topologyKey: Required value: can not be empty,
spec.template.spec.affinity.podAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution[0].podAffinityTerm.topologyKey: Invalid value: "": name part must be non-empty,
spec.template.spec.affinity.podAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution[0].podAffinityTerm.topologyKey: Invalid value: "": name part must consist of alphanumeric characters, '-', '_' or '.', and must start and end with an alphanumeric character (e.g. 'MyName',  or 'my.name',  or '123-abc', regex used for validation is '([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9]')]

调度程序似乎为拓扑键获取了一个空字符串值，即使我的所有节点都有一个与正则表达式匹配的指定键的标签：

$ kubectl describe nodes | grep kubernetes.io/hostname
kubernetes.io/hostname=ip-10-x-x-x.ec2.internal
kubernetes.io/hostname=ip-10-x-x-x.ec2.internal
kubernetes.io/hostname=ip-10-x-x-x.ec2.internal
kubernetes.io/hostname=ip-10-x-x-x.ec2.internal

我没想到从必需到首选的简单更改中会出现这样的问题。我搞砸了什么导致了topologyKey错误？

Answer 1

required 和 preferred 的语法略有不同，请注意podAffinityTerm错误消息路径中的引用：

spec.template.spec.affinity.podAntiAffinity.preferredDuringSchedulingIgnoredDuringExecution[0].podAffinityTerm.topologyKey

首选调度的正确语法是：

affinity:
  podAntiAffinity:
    preferredDuringSchedulingIgnoredDuringExecution:
    - weight: 100
      podAffinityTerm:
        topologyKey: kubernetes.io/hostname
        labelSelector:
          matchExpressions:
          - key: application
            operator: In
            values:
            - {{ $appName }}
          - key: proc
            operator: In
            values:
            - {{ $procName }}

请注意，这weight是一个顶级键，其同级键podAffinityTerm包含topologyKey和labelSelector。