How do you request a change to an ECR Pubic Registry Custom Alias?

Hello.

I checked my AWS account and it seems that once a custom alias is set it cannot be changed.
It is unclear whether AWS Support will allow you to change your custom alias, but I recommend that you contact them.
If possible, it is a good idea to recreate the public registry and then set a custom alias.

To request a change to an Amazon ECR Public Registry Custom Alias, you're correct in observing that the process is not straightforward through the console or CLI. The custom alias field being greyed out in the console UI (Public registry > Settings > Edit) indicates that direct changes are not possible through this interface.

Unfortunately, there isn't a direct CLI method to request or make this change either. The custom alias for a public registry, once set, is not designed to be easily modified due to its impact on image URIs and public accessibility.

Given these limitations, the most appropriate course of action to change a custom alias, especially in the case of a typo, would be to contact AWS Support. They have the necessary tools and permissions to assist with such requests and can guide you through the process of changing your custom alias.

When contacting AWS Support, be prepared to:

1. Explain the situation, including the current custom alias and the desired change.
2. Provide your AWS account ID and the region where your public registry is located.
3. Verify your identity and ownership of the registry.

Keep in mind that changing the custom alias could potentially impact existing workflows or scripts that rely on the current alias, so it's important to plan for any necessary updates to your systems once the change is made.

In summary, going through AWS Support is indeed the recommended and likely the only option to request a change to your ECR Public Registry Custom Alias when you've noticed a typo or need to make modifications after the initial setup.
Sources
Updating registry settings in Amazon ECR public - Amazon ECR Public
Amazon ECR public registries - Amazon ECR Public