DMS connectivity issue with source MySQL and target DocumentDB?


I am planning to migrate RDS MySQL to Document DB, so I've used DMS for migration. I am facing connectivity issue while connecting Source and Target Endpoints.

Note : RDS MySQL is One account and Document DB is in another account, I am enabled the VPC peering between both accounts also I verified the connectivity between them and its working fine.

when I tried to connect the DMS service with source and target facing the connectivity issue which is described below.

Test Endpoint failed: Application-Status: 1020912, Application-Message: Failed to create new client connection Failed to connect to database., Application-Detailed-Message: Error verifying connection: 'No suitable servers found (serverSelectionTryOnce set): [connection timeout calling ismaster on '']'

1 Answer

The error message you're seeing suggests that DMS is unable to establish a connection to the DocumentDB cluster. Here are a few steps to troubleshoot this issue:

  1. Security Groups: Check your security group rules for both your DMS replication instance and your DocumentDB cluster. Ensure that the security group associated with your DMS instance allows outbound traffic to the DocumentDB cluster. Similarly, your DocumentDB cluster's security group should allow inbound traffic from the DMS instance.

  2. Network ACLs: Ensure that your VPC's Network ACLs allow traffic between the DMS instance and DocumentDB cluster. Network ACLs operate at the subnet level and provide an additional layer of security.

  3. Verify VPC Peering: You mentioned you have set up VPC peering between the two accounts. Validate that your VPC peering connection is active and that the correct route table entries have been added in both VPCs. The route tables in each VPC should have entries pointing to the CIDR of the other VPC via the peering connection.

  4. DMS Replication Instance: Ensure that your DMS replication instance is associated with a VPC that has a peering connection with the VPC where the DocumentDB cluster resides.

  5. Endpoint Configuration: Ensure you're using the correct connection details in your DMS endpoints. Specifically, verify that the server name and port number are correct.

  6. Check DocumentDB Cluster Status: Verify that your DocumentDB cluster is active and operating normally. If it's in a failed or degraded state, it may not be able to accept new connections.

If you're still encountering issues after checking all of these points, consider reaching out to AWS support for further assistance. They may be able to provide more detailed logs or insights into what might be causing the connectivity issue.

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answered a year ago
  • Thanks for the update @Ivan Casco. We will check from our side.

  • The above task is ended with error Below is the error.

    Replication task has stopped. Stop Reason FULL_LOAD_ONLY_FINISHED.

    Few tables are migrated as expected, only two error tables. What is the reason for the issue?

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