6. Pod的节点分配

6.1 nodeName

# 编写Yaml文件
apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx
  nodeName: node01

6.2 nodeSelector

# 设置节点的Labels
kubectl label nodes node01 disktype=ssd

# 编写Yaml文件
apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
    env: test
spec:
  containers:
  - name: nginx
    image: nginx
    imagePullPolicy: IfNotPresent
  nodeSelector:
    disktype: ssd

6.3 Affinity and anti-affinity

6.3.1 Node affinity

硬性要求

# 编写Yaml文件
apiVersion: v1
kind: Pod
metadata:
  name: with-node-affinity
spec:
  affinity:
    nodeAffinity:                                                       # 使用node亲和进行判定
      requiredDuringSchedulingIgnoredDuringExecution:                   # 硬性要求
        nodeSelectorTerms:                                              # 节点选择器的条件
        - matchExpressions:                                             # 定义匹配的表达式
          - key: app                                                    # label的key
            operator: In                                                # 定义判断方式多种：In,NotIn,Exists,DoesNotexist,Gt,Lt。
            values:                                                     # label的values
            - nginx1
  containers:
  - name: with-node-affinity
    image: nginx

软性要求

# 编写Yaml文件
apiVersion: v1
kind: Pod
metadata:
  name: with-node-affinity
spec:
  affinity:
    nodeAffinity:
      preferredDuringSchedulingIgnoredDuringExecution:                                  # 软性要求      
      - weight: 1                                                                       # 设置权重，分数越高优先级越高
        preference:
          matchExpressions:
          - key: disktype
            operator: In
            values:
            - ssd
  containers:
  - name: with-node-affinity
    image: nginx

偏好要求

# 设置节点的Labels
kubectl label nodes node02 disktype=ssd
kubectl label nodes node01 app=nginx1
kubectl label nodes node02 app=nginx2

# 编写Yaml文件
apiVersion: v1
kind: Pod
metadata:
  name: with-node-affinity
spec:
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: app
            operator: In
            values:
            - nginx1
            - nginx2
      preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 1
        preference:
          matchExpressions:
          - key: disktype
            operator: In
            values:
            - ssd
  containers:
  - name: with-node-affinity
    image: nginx

6.3.2 Inter-pod affinity and anti-affinity

创建redis

# 编写Yaml文件
apiVersion: apps/v1
kind: Deployment
metadata:
  name: redis-cache
spec:
  selector:
    matchLabels:
      app: store
  replicas: 3
  template:
    metadata:
      labels:
        app: store
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: app
                operator: In
                values:
                - store
            topologyKey: "kubernetes.io/hostname"		# 拓扑域，用来判定拥有哪些标签的节点是同一个位置
      containers:
      - name: redis-server
        image: redis:3.2-alpine

创建web-server

# 编写Yaml文件
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-server
spec:
  selector:
    matchLabels:
      app: web-store
  replicas: 3
  template:
    metadata:
      labels:
        app: web-store
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: app
                operator: In
                values:
                - web-store
            topologyKey: "kubernetes.io/hostname"
        podAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: app
                operator: In
                values:
                - store
            topologyKey: "kubernetes.io/hostname"
      containers:
      - name: web-app
        image: nginx:1.12-alpine