Knative Serving — Serverless 平台

什么是 Knative

Knative 在 Kubernetes 上构建 Serverless 平台，核心特性：

• 自动伸缩：根据请求量自动扩缩容，支持缩容到 0
• 流量分割：支持蓝绿部署、金丝雀发布
• 事件驱动：Knative Eventing 支持事件源和事件处理

安装

# 安装 Knative Serving
kubectl apply -f https://github.com/knative/serving/releases/download/knative-v1.13.0/serving-crds.yaml
kubectl apply -f https://github.com/knative/serving/releases/download/knative-v1.13.0/serving-core.yaml

# 安装网络层（Kourier）
kubectl apply -f https://github.com/knative/net-kourier/releases/download/knative-v1.13.0/kourier.yaml
kubectl patch configmap/config-network \
  --namespace knative-serving \
  --type merge \
  --patch '{"data":{"ingress-class":"kourier.ingress.networking.knative.dev"}}'

Knative Service

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: my-function
  namespace: production
spec:
  template:
    metadata:
      annotations:
        # 自动伸缩配置
        autoscaling.knative.dev/class: kpa.autoscaling.knative.dev
        autoscaling.knative.dev/metric: concurrency
        autoscaling.knative.dev/target: "100"      # 每个 Pod 处理 100 并发
        autoscaling.knative.dev/minScale: "0"       # 缩容到 0
        autoscaling.knative.dev/maxScale: "50"      # 最多 50 个 Pod
        autoscaling.knative.dev/scale-to-zero-pod-retention-period: "1m"
    spec:
      containerConcurrency: 100
      timeoutSeconds: 300
      containers:
      - image: my-function:v1.0
        ports:
        - containerPort: 8080
        resources:
          requests:
            cpu: "100m"
            memory: "128Mi"
          limits:
            cpu: "1"
            memory: "512Mi"
        env:
        - name: TARGET
          value: "World"

  # 流量分割
  traffic:
  - latestRevision: true
    percent: 80
  - revisionName: my-function-v1
    percent: 20
    tag: stable

常用操作

# 查看 Knative Service
kubectl get ksvc -n production

# 查看 Revision
kubectl get revision -n production

# 查看自动伸缩状态
kubectl get pa -n production  # PodAutoscaler

# 发送请求
curl -H "Host: my-function.production.example.com" http://<ingress-ip>/