Repository validation rules

According to the containers naming guide, a container name must be a valid DNS name, conforming to the following naming rules:

Container names must start with a letter or number, and can contain only letters, numbers, and the dash (-) character.
Every dash (-) character must be immediately preceded and followed by a letter or number; consecutive dashes are not permitted in container names.
All letters in a container name must be lowercase.
Container names must be from 3 through 63 characters long.