You can now route traffic from your custom root domains (such as example.com) to your Lightsail container services using Lightsail DNS. Lightsail DNS already supported creating CNAME records mapping to your container services. With this launch, Lightsail DNS supports aliasing your custom root domain to your container service’s default domain which was not possible before. Thus, you can create an A/AAAA record in your Lightsail hosted DNS zone pointing the zone apex to a container service.
Source:: Amazon AWS