Duplicate DNS Records Created in Active Directory

[BTripp1986]

Summary:

When deploying this solution against an existing managed Active Directory there are several DNS records created in Active Directory to point to the newly created instances. There is are 2 records created for the FCI with identical names which point to the 3rd IP/ENI of each EC2 instance. One of these records points to the node which has the MSSQLSERVER role active, and the other record points to the standby instance. This causes DNS queries to the FCI to fail 50% of the time since the second instance is not running the MSSQLSERVER role in the Failover Cluster.

Details: The final step of the SSM automation document created by the cloudformation template is called CompleteFCI. This step takes a parameter from the automation document called SqlFSxFCIName which gets passed as -FCIName {{SqlFSxFCIName}}. When the cluster is created against an existing managed AD it creates the following records:

• 2 records: 1 record pointing to the primary private IP of each EC2 instance
• 1 record pointing to the WFC
• 2 records named from {{SqlFSxFCIName}} with identical names, pointing to the 3rd IP of each of the 2 EC2 instances 3rd IP/ENI. The name of this record is the name to connect to the DB in SQL Server Management Studio, as well as the DNS name to connect to SQL Server

In the Windows Failover Cluster Manager, the first instance is assigned the MSSQLSERVER role, while the second instance is not(active/passive). Because of this DNS queries to {{SqlFSxFCIName}} will hit the standby instance 50% of the time.

[BTripp1986]

I just want to try to draw some attention to this. Please let me know if more information is required, or if anything about this is unclear.