标签与选择器机制

通过标签（Label）和选择器（Selector）实现资源关联与管理

标签配置

• 在资源metadata.labels字段配置
• 命令行操作：

  kubectl label <resource-type> <resource-name> <key=value>
    --overwrite  # 修改现有标签
    --show-labels # 显示全部标签
    -A -l 'env=prod' # 跨命名空间查询
    -l 'tier in (frontend,backend)' # 多值匹配
    -l 'env=prod,app=web' # 多条件匹配

选择器应用

• 在资源spec.selector字段配置
• 命令行使用同上

Deployment控制器

基础操作

# 创建Deployment
kubectl create deploy web-server --image=nginx:1.7.9

# 查看资源状态
kubectl get deploy
kubectl get rs
kubectl get pods --show-labels

滚动更新

# 更新镜像版本
kubectl set image deploy/web-server nginx=nginx:1.9.1

# 查看更新状态
kubectl rollout status deploy web-server
kubectl describe deploy web-server

版本回退

# 查看历史版本
kubectl rollout history deploy/web-server

# 回退操作
kubectl rollout undo deploy/web-server
kubectl rollout undo deploy/web-server --to-revision=2

扩缩容

# 调整副本数量
kubectl scale deploy/web-server --replicas=5

更新暂停与恢复

kubectl rollout pause deploy/web-server
kubectl rollout resume deploy/web-server

配置示例

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-server
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: nginx
        image: nginx:1.9.1

StatefulSet控制器

特性：

• 稳定网络标识：Pod名称格式<statefulset-name>-<ordinal>
• 持久化存储：通过volumeClaimTemplate实现
• 有序部署：按索引顺序创建/删除Pod

无头服务配置

apiVersion: v1
kind: Service
metadata:
  name: db-service
spec:
  clusterIP: None
  selector:
    app: database

StatefulSet配置

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: db-node
spec:
  serviceName: db-service
  replicas: 3
  template:
    metadata:
      labels:
        app: database
    spec:
      containers:
      - name: db
        image: mysql:5.7
        volumeMounts:
        - name: data
          mountPath: /var/lib/mysql
  volumeClaimTemplates:
  - metadata:
      name: data
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: ssd
      resources:
        requests:
          storage: 10Gi

DaemonSet控制器

配置示例

apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: log-collector
spec:
  selector:
    matchLabels:
      name: log-agent
  template:
    metadata:
      labels:
        name: log-agent
    spec:
      tolerations:
      - key: node-role.kubernetes.io/master
        effect: NoSchedule
      containers:
      - name: fluentd
        image: fluentd:latest
        volumeMounts:
        - name: host-logs
          mountPath: /host/log
      volumes:
      - name: host-logs
        hostPath:
          path: /var/log

节点选择

spec:
  template:
    spec:
      nodeSelector:
        logging: enabled

HPA自动扩缩容

指标服务部署

kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

HPA配置

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: app-scaler
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: web-app
  minReplicas: 2
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 60