# 查询后端ECS的实例ID
#### 操作场景
本章节通过示例演示如何调用API来获取负载均衡器下的Member对应的ECS的ID。
#### 前提条件
已创建负载均衡器、后端服务器组和后端服务器。
#### 操作步骤
发送"GET /v3/{project_id}/elb/members"，project_id为项目ID，其他查询条件根据实际使用情况添加，具体可以参考API文档。在Request Header中增加"X-Auth-Token"。
查看请求响应结果，从响应字段中的instance_id获取ECS ID。
- 请求成功时，响应参数如下：
  ```
  {
      "request_id": "0df89f0ad2ecf0e0a5688978d28e9a6d",
      "members": [
          {
              "weight": 1,
              "admin_state_up": true,
              "project_id": "04dd36f9c0000fe22f9fc00b409f1sq1",
              "address": "192.168.2.96",
              "protocol_port": 80,
              "id": "0b7c1e58-5940-41c1-a7c5-dbe4b3f23e4w",
              "operating_status": ONLINE,
              "status": [
                  {
                      "listener_id": "73bea9d6-fb7f-47cc-b949-c3382abb1f46",
                      "operating_status": "ONLINE"
                  }
              ],
              "instance_id": "6985a0dc-5884-40f2-9426-15fb4bab8f1d", // ECS ID
              "device_id": "6985a0dc-5884-40f2-9426-15fb4bab8f1d",
              "device_owner": "compute:az1",
              "member_type": "instance",
              "created_at": "2023-05-15T07:15:43Z",
              "updated_at": "2023-05-15T07:15:53Z",
              "loadbalancer_id": "955af176-4275-49ac-b47e-05912x9dj33c",
              "loadbalancers": [
                  {
                      "id": "955af176-4275-49ac-b47e-05912x9dj33c"
                  }
              ],
              "pool_id": "b6e6fdcf-4f4d-4d21-95ca-925143af6de8",
              "ip_version": "v4",
              "subnet_cidr_id": "b765590e-905e-4e13-9d34-0e0ea9de2k9d"
          }
      ],
      "page_info": {
          "previous_marker": "0b7c1e58-5940-41c1-a7c5-dbe4b3f83506",
          "current_count": 1
      }
  }
  ```
  
- 请求异常时，错误码请参见 [错误码](https://support.huaweicloud.com/api-elb/ErrorCode.html)。