Add a data source-ApsaraDB for OceanBase (Deprecated)(OceanBase)-阿里云帮助中心

Problem
When you add an RDS MySQL data source on the Data Source Management page, an error occurs:
```
Cause of failure: [DB_QUERY_ERROR]{"jdbcUrl":"jdbc:mysq://10.10.10.1:5119?allowLoadLocallnfile=false&autoDeserialize=false&allowLocalInfile=false&allowUrlInLocalInfile=false&useSSL=false","message":"com.oceanbase.oms.cm.client.exception.CmServerException:failures occured while executing command,skip remaining command;errorcode:BAD_GATEWAY"} .
```
Solution
If this error occurs, check the following items:
- Confirm that the RDS MySQL whitelist is correctly configured
  OMS automatically creates a whitelist group on the RDS instance. The group name is similar to ob_oms_cn_xxxxx, and the group contains the CIDR block of Data Transmission Service.
  The task to add the whitelist depends on other tasks on the RDS instance. This task can fail for various reasons. If the task fails, manually add the CIDR block that is displayed on the OMS data source page to any RDS whitelist group.
- Ensure that the username and password are correct
  The error message "Access denied for user 'username'@'x.x.x.x' (using password: YES)" indicates that the password that you entered for the data source is incorrect.
Symptoms
When you configure a data migration project, an error occurs while adding an RDS MySQL data source:
```
Cause of failure: [DB_QUERY_ERROR]{"jdbcUrl":"jdbc:mysq://10.10.10.1:4100?allowLoadLocallnfile=false&autoDeserialize=false&allowLocalInfile=false&allowUrlInLocalInfile=false&useSSL=false","message":"com.oceanbase.oms.cm.client.exception.CmServerException:java.net.UnknownHostException:i3lhk5fxzu1cw;errorcode:BAD_GATEWAY"} .
```
The following items have been checked:
- The whitelist is correctly configured.
- You can connect to the RDS instance remotely, but not from the Internet.
- All error messages report an UnknownHostException.
Possible cause
The "Unknown Host" error indicates that resources for the OMS instance were not allocated successfully. When you purchase a Data Transmission Service instance for the first time, it can take 10 to 15 minutes for the resources to be created.
Solution
Wait for the instance to be created. Then, retry the configuration.