需求：

Pod和Node之間的關(guān)系

某些Pod優(yōu)先選擇有ssd=true標(biāo)簽的節(jié)點(diǎn)，如果沒有在考慮部署到其它節(jié)點(diǎn)；
某些Pod需要部署在ssd=true和type=physical的節(jié)點(diǎn)上分唾，但是優(yōu)先部署在ssd=true的節(jié)點(diǎn)上隙赁；

Pod和Pod之間的關(guān)系

同一個(gè)應(yīng)用的Pod不同的副本或者同一個(gè)項(xiàng)目的應(yīng)用盡量或必須不部署在同一個(gè)節(jié)點(diǎn)或者符合某個(gè)標(biāo)簽的一類節(jié)點(diǎn)上或者不同的區(qū)域；
相互依賴的兩個(gè)Pod盡量或必須部署在同一個(gè)節(jié)點(diǎn)上或者同一個(gè)域內(nèi)。

Affinity分類

image.png

節(jié)點(diǎn)親和力配置詳解

apiVersion: v1
kind: Pod
metadata:
  name: with-node-affinity
spec:
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:      # 硬親和力配置
        nodeSelectorTerms:      # 節(jié)點(diǎn)選擇器配置莫换，可以配置多個(gè)matchExpressions（滿足其一），每個(gè)matchExpressions下可以配置多個(gè)key、value類型的選擇器（都需要滿足）拉岁，其中values可以配置多個(gè)（滿足其一）
        - matchExpressions:
          - key: kubernetes.io/e2e-az-name
            operator: In      # 標(biāo)簽匹配的方式 
                                     # In：相當(dāng)于key = value的形式
                                     # NotIn：相當(dāng)于key != value的形式 
                                     # Exists：節(jié)點(diǎn)存在label的key為指定的值即可坷剧，不能配置values字段
                                     # DoesNotExist：節(jié)點(diǎn)不存在label的key為指定的值即可，不能配置values字段
            values:
            - e2e-az1
            - az-2
      preferredDuringSchedulingIgnoredDuringExecution:      # 軟親和力配置
      - weight: 1      # 軟親和力的權(quán)重喊暖，權(quán)重越高優(yōu)先級(jí)越大惫企，范圍1-100
        preference:      # 軟親和力配置項(xiàng)，和weight同級(jí)陵叽，可以配置多個(gè)
          matchExpressions:      # 和硬親和力一致
          - key: another-node-label-key
            operator: In      # 標(biāo)簽匹配的方式 
                                     # In：相當(dāng)于key = value的形式
                                     # NotIn：相當(dāng)于key != value的形式 
                                     # Exists：節(jié)點(diǎn)存在label的key為指定的值即可狞尔，不能配置values字段
                                     # DoesNotExist：節(jié)點(diǎn)不存在label的key為指定的值即可，不能配置values字段
            values:
            - another-node-label-value
  containers:
  - name: with-node-affinity
    image: nginx

Pod親和力和反親和力詳解

apiVersion: v1
kind: Pod
metadata:
  name: with-pod-affinity
spec:
  affinity:
    podAffinity:      # pod親和力配置
      requiredDuringSchedulingIgnoredDuringExecution:      # 硬親和力配置
      - labelSelector:      # Pod的lableSelector配置巩掺，可以配置多個(gè)
          matchExpressions:      # 配置和節(jié)點(diǎn)親和力配置一致
          - key: security
            operator: In      # 配置和節(jié)點(diǎn)親和力一致
            values:
            - S1
        topologyKey: failure-domain.beta.kubernetes.io/zone      # 匹配的拓?fù)溆虻膋ey偏序，也就是節(jié)點(diǎn)上label的key，key和value相同的為同一個(gè)域胖替，可以用于標(biāo)注不同的機(jī)房和地區(qū)
    podAntiAffinity:      # pod反親和力配置
      preferredDuringSchedulingIgnoredDuringExecution:      # 軟親和力配置
      - weight: 100
        podAffinityTerm:
          labelSelector:
            matchExpressions:
            - key: security
              operator: In
              values:
              - S2
          namespaces:      # 和哪個(gè)命名空間的Pod進(jìn)行匹配研儒，空為default命名空間，可以寫多個(gè)namespace
          - default
          topologyKey: failure-domain.beta.kubernetes.io/zone      # 匹配的拓?fù)溆虻膋ey独令，也就是節(jié)點(diǎn)上label的key殉摔，key和value相同的為同一個(gè)域，可以用于標(biāo)注不同的機(jī)房和地區(qū)
  containers:
  - name: with-pod-affinity
    image: nginx

示例1：同一個(gè)應(yīng)用部署在不同的宿主機(jī)

使用pod的親和力app=must-be-diff-nodes记焊， 通過節(jié)點(diǎn)默認(rèn)label topologyKey: kubernetes.io/hostname 實(shí)現(xiàn)每個(gè)pod都調(diào)度到不同的宿主機(jī)

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: must-be-diff-nodes
  name: must-be-diff-nodes
  namespace: kube-public
spec:
  replicas: 3
  selector:      # Pod選擇器配置，可以配置多個(gè)
    matchLabels:      # 配置和節(jié)點(diǎn)親和力一致
      app: must-be-diff-nodes
  template:
    metadata:
      labels:
        app: must-be-diff-nodes
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: app
                operator: In      # 配置和節(jié)點(diǎn)親和力一致
                values:
                - must-be-diff-nodes
            topologyKey: kubernetes.io/hostname      # 匹配的拓?fù)溆虻膋ey栓撞，也就是節(jié)點(diǎn)上label的key遍膜，key和value相同的為同一個(gè)域，可以用于標(biāo)注不同的機(jī)房和地區(qū)
      containers:
      - image: nginx
        imagePullPolicy: IfNotPresent
        name: must-be-diff-nodes

示例2：同一個(gè)應(yīng)用不同副本固定節(jié)點(diǎn)

使用pod反親和力app=store瓤湘，通過topologyKey: "kubernetes.io/hostname"實(shí)現(xiàn)多副本的pod瓢颅，不調(diào)度到同一臺(tái)節(jié)點(diǎn)上

apiVersion: apps/v1
kind: Deployment
metadata:
  name: redis-cache
spec:
  selector:
    matchLabels:
      app: store
  replicas: 3
  template:
    metadata:
      labels:
        app: store
    spec:
      nodeSelector:
          app: store
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: app
                operator: In
                values:
                - store
            topologyKey: "kubernetes.io/hostname"
      containers:
      - name: redis-server
        image: redis:3.2-alpine

示例3：應(yīng)用和緩存盡量部署在同一個(gè)域內(nèi)

使用pod的硬親和性和軟親和性，實(shí)現(xiàn)pod app=store的label盡量部署在同一個(gè)域中

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:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 100
            podAffinityTerm:
              labelSelector:
                matchExpressions:
                - key: app
                  operator: In
                  values:
                  - store
              topologyKey: "kubernetes.io/hostname"
      containers:
      - name: web-app
        image: nginx:1.16-alpine

示例4：盡量調(diào)度到高配置服務(wù)器

通過節(jié)點(diǎn)的硬親和性弛说，一次匹配ssd=true挽懦，weight100，weight10

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: prefer-ssd
  name: prefer-ssd
  namespace: kube-public
spec:
  replicas: 3
  selector:
    matchLabels:
      app: prefer-ssd
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: prefer-ssd
    spec:
      affinity:
        nodeAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - preference:
              matchExpressions:
              - key: ssd
                operator: In
                values:
                - "true"
              - key: master
                operator: NotIn
                values:
                - "true"
            weight: 100
          - preference:
              matchExpressions:
              - key: type
                operator: In
                values:
                - physical
            weight: 10
      containers:
      - env:
        - name: TZ
          value: Asia/Shanghai
        - name: LANG
          value: C.UTF-8
        image: nginx
        imagePullPolicy: IfNotPresent
        name: prefer-ssd

TopologyKey配置詳解

匹配的拓?fù)溆虻膋ey木人，也就是節(jié)點(diǎn)上label的key信柿，key和value相同的為同一個(gè)域，可以用于標(biāo)注不同的機(jī)房和地區(qū)

image.png

image.png

示例：同一個(gè)應(yīng)用多區(qū)域部署

通過pod的硬親和性醒第，和topologyKey node節(jié)點(diǎn)的同一個(gè)key渔嚷，不同的value實(shí)現(xiàn)多區(qū)域部署

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: must-be-diff-zone
  name: must-be-diff-zone
  namespace: kube-public
spec:
  replicas: 3
  selector:
    matchLabels:
      app: must-be-diff-zone
  template:
    metadata:
      labels:
        app: must-be-diff-zone
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: app
                operator: In
                values:
                - must-be-diff-zone
            topologyKey: region      # region為node的label，上述圖中稠曼，region分別=daxing形病、chaoyang
      containers:
      - image: nginx
        imagePullPolicy: IfNotPresent
        name: must-be-diff-zone