k8s中应用容器随redis集群自动重启

背景：

业务系统需要使用redis集群做缓存，但是redis集群不稳定会出现宕机问题，宕机后redis自动重启，但是业务系统不能自动重连redis。

改进方案：

当redis集群故障服务不能使用时，业务系统也要随redis一起重启。在业务系统的容器中添加redis服务探查程序。更好的方式是业务系统支持redis的服务的自动重连

apiVersion: apps/v1
kind: Deployment
metadata:
  name: business-app-with-monitor
spec:
  replicas: 3
  template:
    metadata:
      labels:
        app: business-app
    spec:
      initContainers:
      - name: redis-preflight-check
        image: busybox:1.35
        command: 
        - /bin/sh
        - -c
        - |
          # 简化的启动前检查
          echo "执行 Redis 集群启动前检查..."
          for i in 0 1 2; do
            if ! nc -z -w 5 redis-$i.redis-headless 6379; then
              echo "❌ redis-$i 不可用"
              exit 1
            fi
            echo "✅ redis-$i 连接成功"
          done
          echo "所有 Redis 节点就绪"
      
      containers:
      # 主业务容器
      - name: business-app
        image: your-business-app:latest
        ports:
        - containerPort: 8080
        env:
        - name: REDIS_CLUSTER_NODES
          value: "redis-0.redis-headless:6379,redis-1.redis-headless:6379,redis-2.redis-headless:6379"
        livenessProbe:
          exec:
            command:
            - /bin/sh
            - -c
            - |
              # 检查应用是否健康，同时检查 Redis 连接
              if ! curl -f http://localhost:8080/health; then
                exit 1
              fi
              
              # 检查 Redis 集群状态
              if ! echo "CLUSTER INFO" | nc -w 3 redis-0.redis-headless 6379 | grep -q "cluster_state:ok"; then
                echo "Redis 集群异常，触发重启"
                exit 1
              fi
          initialDelaySeconds: 30
          periodSeconds: 15
          timeoutSeconds: 10
          failureThreshold: 2
      
      # Redis 监控 Sidecar
      - name: redis-monitor
        image: busybox:1.35
        command:
        - /bin/sh
        - -c
        - |
          echo "启动 Redis 集群监控..."
          
          while true; do
            echo "$(date): 检查 Redis 集群状态..."
            
            # 检查集群健康状态
            cluster_healthy=false
            for node in redis-0.redis-headless:6379 redis-1.redis-headless:6379 redis-2.redis-headless:6379; do
              host=${node%:*}
              port=${node#*:}
              
              if echo "CLUSTER INFO" | nc -w 5 $host $port 2>/dev/null | grep -q "cluster_state:ok"; then
                cluster_healthy=true
                break
              fi
            done
            
            if [ "$cluster_healthy" = "false" ]; then
              echo "❌ $(date): Redis 集群状态异常，触发业务容器重启"
              # 向业务容器发送 SIGTERM 信号，触发重启
              kill -TERM 1
              sleep 10
            else
              echo "✅ $(date): Redis 集群状态正常"
            fi
            
            sleep 30
          done
        resources:
          requests:
            memory: "32Mi"
            cpu: "10m"