kubernetes - 如何跨节点分布部署？

Question

我有一个 Kubernetes 部署，看起来像这样(用“....”替换了名称和其他内容):

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# and an empty file will abort the edit. If an error occurs while saving this file will be
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apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "3"
    kubernetes.io/change-cause: kubectl replace deployment ....
      -f - --record
  creationTimestamp: 2016-08-20T03:46:28Z
  generation: 8
  labels:
    app: ....
  name: ....
  namespace: default
  resourceVersion: "369219"
  selfLink: /apis/extensions/v1beta1/namespaces/default/deployments/....
  uid: aceb2a9e-6688-11e6-b5fc-42010af000c1
spec:
  replicas: 2
  selector:
    matchLabels:
      app: ....
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 1
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: ....
    spec:
      containers:
      - image: gcr.io/..../....:0.2.1
        imagePullPolicy: IfNotPresent
        name: ....
        ports:
        - containerPort: 8080
          protocol: TCP
        resources:
          requests:
            cpu: "0"
        terminationMessagePath: /dev/termination-log
      dnsPolicy: ClusterFirst
      restartPolicy: Always
      securityContext: {}
      terminationGracePeriodSeconds: 30
status:
  availableReplicas: 2
  observedGeneration: 8
  replicas: 2
  updatedReplicas: 2

我观察到的问题是 Kubernetes 将两个副本(在我要求的部署中需要两个)放置在同一节点上。如果该节点出现故障，我会丢失两个容器并且服务也会离线。

我希望 Kubernetes 做的是确保它不会在容器类型相同的同一节点上加倍容器 - 这只会消耗资源，不会提供任何冗余。我浏览了有关部署、副本集、节点等的文档，但找不到任何可以让我告诉 Kubernetes 执行此操作的选项。

有没有办法告诉 Kubernetes 我想要一个容器在节点之间有多少冗余？

编辑:我不确定标签是否有效；标签限制节点的运行位置，以便它可以访问本地资源(SSD)等。我想做的就是确保节点离线时不会停机。

Answer 1

There is now a proper way of doing this.如果您只想将其分布在所有节点上，则可以使用“kubernetes.io/hostname”中的标签。这意味着如果您有一个 Pod 的两个副本和两个节点，如果它们的名称不同，每个副本都应该获得一个。

示例:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-service
  labels:
    app: my-service
spec:
  replicas: 2
  selector:
    matchLabels:
      app: my-service
  template:
    metadata:
      labels:
        app: my-service
    spec:
      topologySpreadConstraints:
      - maxSkew: 1
        topologyKey: kubernetes.io/hostname
        whenUnsatisfiable: DoNotSchedule
        labelSelector:
          matchLabels:
            app: my-service
      containers:
      - name: pause
        image: k8s.gcr.io/pause:3.1