节点选择器

nodeSelector

如下：

apiVersion: v1
kind: Pod
metadata:
  name: pod-nodeselector
spec:
  containers:
  - name: myapp
    image: ikubernetes/myapp:v1
  nodeSelector:
    disktype: ssd

上面定义只有调度到符合标签为disktype=ssd得node。

nodeName

当确认要让某个Pod允许在指定的节点上，如下：

apiVersion: v1
kind: Pod
metadata:
  name: pod-nodename
spec:
  containers:
  - name: myapp
    image: ikubernetes/myapp:v1
  nodeName: 172.16.1.130     # 节点名字

节点亲和性

nodeAffinity

nodeAffinity有两种，优选和必选，其为：preferredDuringSchedulingIgnoredDuringExecution和requiredDuringSchedulingIgnoredDuringExecution。

requiredDuringSchedulingIgnoredDuringExecution的例子如下：

apiVersion: v1
kind: Pod
metadata:
  name: pod-nodeaffinity-required
spec:
  containers:
  - name: myapp
    image: ikubernetes/myapp:v1
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: disktype
            operator: In
            values: ["ssd", "harddisk"]

其中operator支持In,NotIn, Exists, DoesNotExist. Gt, and Lt。

preferredDuringSchedulingIgnoredDuringExecution的例子如下：

apiVersion: v1
kind: Pod
metadata:
  name: pod-nodeaffinity-preferred
spec:
  containers:
  - name: myapp
    image: ikubernetes/myapp:v1
  affinity:
    nodeAffinity:
      preferredDuringSchedulingIgnoredDuringExecution:
      - preference:
          matchExpressions:
          - key: disktype
            operator: In
            values: ["ssd", "harddisk"]
        weight: 60

podAffinity

podAffinity也有preferredDuringSchedulingIgnoredDuringExecution和requiredDuringSchedulingIgnoredDuringExecution，其定义方式和nodeAffinity一样

apiVersion: v1
kind: Pod
metadata:
  name: pod-first
  labels:
    app: myapp
    row: fronted
spec:
  containers:
  - name: myapp
    image: ikubernetes/myapp:v1
---
apiVersion: v1
kind: Pod
metadata:
  name: pod-second
  labels:
    app: db
    row: backend
spec:
  containers:
  - name: db
    image: busybox
    imagePullPolicy: IfNotPresent
    command:
    - "/bin/sh"
    - "-c"
    - "sleep 3600"
  affinity:
    podAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
      - labelSelector:
          matchExpressions:
          - key: app
            operator: In
            values: ["myapp"]
        topologyKey: kubernetes.io/hostname

podAntiAffinity

pod的反亲和性。

apiVersion: v1
kind: Pod
metadata:
  name: pod-first
  labels:
    app: myapp
    row: fronted
spec:
  containers:
  - name: myapp
    image: ikubernetes/myapp:v1
---
apiVersion: v1
kind: Pod
metadata:
  name: pod-second
  labels:
    app: db
    row: backend
spec:
  containers:
  - name: db
    image: busybox
    imagePullPolicy: IfNotPresent
    command:
    - "/bin/sh"
    - "-c"
    - "sleep 3600"
  affinity:
    podAntiAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
      - labelSelector:
          matchExpressions:
          - key: app
            operator: In
            values: ["myapp"]
        topologyKey: kubernetes.io/hostname

污点调度方式

taints是Node级别的，可以通过kubectl explain node.spec.taints来查看。

# kubectl explain node.spec.taints
KIND:     Node
VERSION:  v1
RESOURCE: taints <[]Object>
DESCRIPTION:
     If specified, the node's taints.
     The node this Taint is attached to has the "effect" on any pod that does
     not tolerate the Taint.
FIELDS:
   effect    <string> -required-
     Required. The effect of the taint on pods that do not tolerate the taint.
     Valid effects are NoSchedule, PreferNoSchedule and NoExecute.
   key    <string> -required-
     Required. The taint key to be applied to a node.
   timeAdded    <string>
     TimeAdded represents the time at which the taint was added. It is only
     written for NoExecute taints.
   value    <string>
     Required. The taint value corresponding to the taint key.

其中effect定义对Pod的排斥效果：

• NoSchdule：仅影响调度过程，对现存在的Pod不产生影响；
• NoExecute：不仅影响调度，而且还影响现存Pod，不容忍的Pod对象将被驱逐；
• PreferNoSchedule：

管理污点用kubectl taint.

tolerations容忍度是定义在Pod上的。

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9
        imagePullPolicy: IfNotPresent 
        ports:
        - containerPort: 80
      tolerations:
      - key: "node-type"
        operator: Equal
        value: dev
        effect: NoSchedule
        tolerationSeconds: 20