Question about the new AWS RDS CA When updating the database to use the new CA, you get this popup:


  Before scheduling the CA certificate rotation, update client
  applications that connect to your database to use the new CA
  certificate. Not doing this will cause an interruption of connectivity
  between your applications and your database.


Does anyone know if this is required? We didn't have to import the CA originally, so why would we have to now? If it's a matter of the new root CA not being part of the trust chain of older distros, does anyone know if Ubuntu 18.04 has the new CA in its ca-certificates package yet?

Thanks!
I am not completely sure that Ubuntu 18.04 will have this CA in their certificates packages because they announced this CA replacement recently. 

If you are using the SSL/TLS to connect to your DB instances, then only this will be required, otherwise you can simply ignore this. 

You can find the complete details of this CA certificate rotation and it's impact in the AWS blog