Kubernetes架构

控制平面

控制平面是K8s的大脑，包含API Server、etcd、Scheduler和Controller Manager。

┌─────────────────────────────────────────────┐
│              控制平面 (Control Plane)         │
├─────────────┬─────────────┬─────────────────┤
│ API Server  │    etcd     │   Scheduler     │
├─────────────┼─────────────┼─────────────────┤
│ Controller  │  Cloud      │                 │
│  Manager    │ Controller  │                 │
└─────────────┴─────────────┴─────────────────┘
                    │
                    ▼
┌─────────────────────────────────────────────┐
│              数据平面 (Data Plane)            │
├─────────────┬─────────────┬─────────────────┤
│   kubelet   │ kube-proxy  │ Container       │
│             │             │ Runtime         │
└─────────────┴─────────────┴─────────────────┘

核心组件

# K8s核心组件职责
controlPlane:
  apiServer:
    description: "集群网关，所有操作的入口"
    port: 6443
  etcd:
    description: "分布式KV存储，保存集群状态"
    port: 2379
  scheduler:
    description: "Pod调度，选择最优节点运行"
  controllerManager:
    description: "控制循环，维护期望状态"
    
dataPlane:
  kubelet:
    description: "节点代理，管理Pod生命周期"
  kubeProxy:
    description: "网络代理，实现Service负载均衡"
  containerRuntime:
    description: "容器运行时，如containerd/CRI-O"

Pod生命周期

# Pod配置示例
apiVersion: v1
kind: Pod
metadata:
  name: web-app
  labels:
    app: web
spec:
  containers:
  - name: nginx
    image: nginx:alpine
    ports:
    - containerPort: 80
    resources:
      requests:
        cpu: "100m"
        memory: "128Mi"
      limits:
        cpu: "500m"
        memory: "256Mi"
    livenessProbe:
      httpGet:
        path: /health
        port: 80
      initialDelaySeconds: 10
      periodSeconds: 5
  restartPolicy: Always

Deployment与ReplicaSet

# Deployment配置
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  strategy:
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: web
        image: myapp:v1.2.0

命名空间与资源配额

# 命名空间资源限制
apiVersion: v1
kind: Namespace
metadata:
  name: production
---
apiVersion: v1
kind: ResourceQuota
metadata:
  name: prod-quota
  namespace: production
spec:
  hard:
    requests.cpu: "10"
    requests.memory: 20Gi
    limits.cpu: "20"
    limits.memory: 40Gi
    pods: "50"