python - kubernetes中grpc服务健康检查实现

• 概述
  kubernetes本身不支持gRPC健康检查，本文记录使用 ‘grpc-health-probe’ 实现grpc服务的健康检查
  ‘grpc-health-probe’，这是 Kubernetes 原生的健康检查 gRPC 应用程序的方法
  

  官方参考文档：https://kubernetes.io/zh-cn/blog/2018/10/01/health-checking-grpc-servers-on-kubernetes/

• 示例

  • 下载grpc-health-probe文件
    按需下载指定版本grpc-health-probe文件

    下载地址：https://github.com/grpc-ecosystem/grpc-health-probe/releases

  • 配置grpc-health-probe
    将静态编译的grpc_health_probe打在容器映像中
    Dockerfile：

    COPY ocr/data/grpc_health_probe_v0.4.1 /bin/grpc_health_probe
    
    RUN chmod +x /bin/grpc_health_probe
    

  • 健康检查接口实现

    • 创建health.proto文件

    syntax = "proto3";
    
    // 定义grpc请求消息体
    message HealthCheckRequest {
      string service = 1;
    }
    
    // 定义grpc返回消息体
    message HealthCheckResponse {
      enum ServingStatus {
        UNKNOWN = 0;
        SERVING = 1;
        NOT_SERVING = 2;
      }
      ServingStatus status = 1;
    }
    
    // 定义服务接口
    service Health {
      rpc Check(HealthCheckRequest) returns (HealthCheckResponse);
    }
    

    • 健康检查接口实现

     class HealthServer(health_pb2_grpc.HealthServicer):
        """
        定义类继承HealthServicer
        """
    
        def __init__(self):
            pass
    
        def Check(self, request, context):
            """
            健康检查接口，实现proto文件中的服务接口
            """
            return health_pb2.HealthCheckResponse(status=HealthCheckResponse.ServingStatus.SERVING)
    
    
        def run(host, port):
            """
            运行ocr服务
            :param host:
            :param port:
            :return:
            """
            server = grpc.server(futures.ThreadPoolExecutor(max_workers=5))
            health_pb2_grpc.add_HealthServicer_to_server(HealthServer(), server)
            server.add_insecure_port(f'{host}:{port}')
            server.start()
            print('Grpc server connect successful!')
            # 启动服务，等待退出
            try:
                while True:
                    time.sleep(600)
            except KeyboardInterrupt:
                server.stop(0)
    
    
        if __name__ == '__main__':
            run(host='0.0.0.0', port='8001')
    

    • 容器中测试

    \bin\grpc-health-probe -addr :8001
    返回 SERVING
    

    • kubernetes中配置

    spec:
      containers:
      - name: server
        image: "[YOUR-DOCKER-IMAGE]"
        ports:
        - containerPort: 8001
        readinessProbe:
          exec:
            command: ["/bin/grpc_health_probe", "-addr=:8001"]
          initialDelaySeconds: 5
        livenessProbe:
          exec:
            command: ["/bin/grpc_health_probe", "-addr=:8001"]
          initialDelaySeconds: 10
    

  
  
  

  参考文档：
  grpc_health_probe配置：https://github.com/grpc-ecosystem/grpc-health-probe/