Kubernetes架构与核心概念详解

Kubernetes架构与核心概念详解

1. Kubernetes概述

Kubernetes（K8s）是Google开源的容器编排平台，用于自动化容器化应用的部署、扩展和管理。

2. Kubernetes架构

2.1 控制平面组件

• kube-apiserver：API服务器，所有操作的入口
• etcd：分布式键值存储，保存集群状态
• kube-controller-manager：运行控制器
• kube-scheduler：调度Pod到节点

2.2 节点组件

• kubelet：管理Pod生命周期
• kube-proxy：网络代理
• container runtime：容器运行时（Docker/containerd）

3. Pod

3.1 Pod定义

apiVersion: v1 kind: Pod metadata: name: nginx labels: app: nginx spec: containers: - name: nginx image: nginx:1.21 ports: - containerPort: 80 resources: limits: memory: "128Mi" cpu: "500m" requests: memory: "64Mi" cpu: "250m"

3.2 多容器Pod

spec: containers: - name: main image: nginx - name: sidecar image: busybox command: ['sh', '-c', 'tail -f /var/log/nginx/access.log']

4. Deployment

4.1 Deployment定义

apiVersion: apps/v1 kind: Deployment metadata: name: nginx-deployment spec: replicas: 3 selector: matchLabels: app: nginx template: metadata: labels: app: nginx spec: containers: - name: nginx image: nginx:1.21 ports: - containerPort: 80

4.2 滚动更新

spec: strategy: type: RollingUpdate rollingUpdate: maxSurge: 1 maxUnavailable: 0

5. Service

5.1 ClusterIP Service

apiVersion: v1 kind: Service metadata: name: nginx-svc spec: type: ClusterIP selector: app: nginx ports: - port: 80 targetPort: 80

5.2 NodePort Service

spec: type: NodePort selector: app: nginx ports: - port: 80 targetPort: 80 nodePort: 30080

5.3 LoadBalancer Service

spec: type: LoadBalancer selector: app: nginx ports: - port: 80 targetPort: 80

6. ConfigMap与Secret

6.1 ConfigMap

apiVersion: v1 kind: ConfigMap metadata: name: app-config data: database.url: "postgres://localhost:5432" log.level: "info"

6.2 Secret

apiVersion: v1 kind: Secret metadata: name: app-secrets type: Opaque data: # echo -n "password" | base64 password: cGFzc3dvcmQ=

7. Ingress

7.1 Ingress定义

apiVersion: networking.k8s.io/v1 kind: Ingress metadata: name: app-ingress spec: rules: - host: app.example.com http: paths: - path: / pathType: Prefix backend: service: name: nginx-svc port: number: 80

7.2 TLS配置

spec: tls: - hosts: - app.example.com secretName: app-tls

8. 总结

Kubernetes提供了完整的容器编排能力，通过Pod、Deployment、Service等资源对象，可以实现应用的自动化部署、扩展和管理。