What Should I Do If an ECS Cannot Connect to a DDS DB Instance?

Perform the following steps to identify the problem: The following uses the cluster instance as an example.

1. Check whether the ECS and DDS DB instance are located in the same VPC.
   • If yes, go to 2.
   • If no, create an ECS in the VPC where the DDS DB instance is located.

2. Check whether a security group has been added to the ECS.
   • If yes, check whether the security group rules are suitable. For details, see the security group description in section Setting a Security Group. Then, go to 3.
   • If no, go to the VPC console from the ECS details page and click Security Groups to add a security group.

3. On the ECS, check whether the DDS DB instance address port can be connected.

   telnet <DB instance address> {8635}

   • If yes, the network is normal. Check the database account and password. For details, see section Connecting to a Cluster Instance Over Private Networks.
   • If no, contact post-sales technical support for troubleshooting.