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/