Custom DNS for EC2 instance

Here are the general steps to assign a custom domain name to your EC2 instance using Route 53:

First, register your domain name with a domain registrar such as Amazon Route 53, or transfer your existing domain to Route 53.

Next, create a hosted zone in Route 53 that corresponds to your domain name.

Create an "A" record in the hosted zone that maps your domain name to the Elastic IP address of your EC2 instance.

EC2 instances indeed come with Public DNS names that allow access to your instances via the internet. However, it's important to note that these Public DNS names are not designed to be stable over time. They can change when instances are stopped and started, or when there are changes to the underlying infrastructure. This can potentially lead to disruptions if you rely on the Public DNS names for your application's accessibility.

To achieve a more stable and reliable solution for handling traffic to your instances, we recommend utilising an Elastic Load Balancer (ELB). An ELB provides a single endpoint that distributes incoming traffic across multiple instances, increasing the availability and fault tolerance of your application.

You can also have a look on our post Why can't I configure ACM certificates for my website hosted on an EC2 instance. Should you need more specific guidance, please provide us with more details about your use case and/or compliance requirements.