Kubernetes 容器编排指南

为什么需要 K8s？

Kubernetes 是容器编排的事实标准，能自动化部署、扩展和管理容器化应用。

核心概念

Pod

K8s 最小部署单元，包含一个或多个容器。

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
spec:
  containers:
  - name: nginx
    image: nginx:1.21
    ports:
    - containerPort: 80

Deployment

管理 Pod 的副本和更新策略。

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

Service

服务发现和负载均衡。

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

ConfigMap 和 Secret

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
data:
  DATABASE_URL: "postgres://localhost/db"
  LOG_LEVEL: "info"

常用命令

# 查看资源
kubectl get pods
kubectl get deployments
kubectl get services

# 查看日志
kubectl logs <pod-name>

# 进入容器
kubectl exec -it <pod-name> -- /bin/bash

# 扩缩容
kubectl scale deployment nginx --replicas=5

# 滚动更新
kubectl set image deployment/nginx nginx=nginx:1.22

健康检查

livenessProbe:
  httpGet:
    path: /health
    port: 8080
  initialDelaySeconds: 30
  periodSeconds: 10

readinessProbe:
  httpGet:
    path: /ready
    port: 8080
  initialDelaySeconds: 5
  periodSeconds: 5

资源限制

resources:
  requests:
    memory: "64Mi"
    cpu: "250m"
  limits:
    memory: "128Mi"
    cpu: "500m"

总结

Kubernetes 是云原生时代的核心技能，掌握它能构建高可用的分布式系统。