Is ARN customisable and persistent?

Question

Sorry for a newbie question, just wondering if ARN is similar in concept to URN.

Take a book as an example, an URN of a book could be urn:isbn:12345678, which 12345678 is a globally unique number and could not be reused for other books.

If ARN has similar features, could there be a case that no more unique ARN are available for resource creation once it hit the limit?

Answer

This [reference](https://docs.aws.amazon.com/general/latest/gr/aws-arns-and-namespaces.html) will provide a very good insight into what ARN is. Amazon Resource Names (ARNs) uniquely identify AWS resources. We require an ARN when you need to specify a resource unambiguously across all of AWS, such as in IAM policies, Amazon Relational Database Service (Amazon RDS) tags, and API calls.

The ARN format is as follows

arn:partition:service:region:account-id:resource-id
arn:partition:service:region:account-id:resource-type/resource-id
arn:partition:service:region:account-id:resource-type:resource-id

where resource-id is a resource identifier. This part of the ARN can be the name or ID of the resource or a resource path. For example, user/Bob for an IAM user or instance/i-1234567890abcdef0 for an EC2 instance. Some resource identifiers include a parent resource (sub-resource-type/parent-resource/sub-resource) or a qualifier such as a version (resource-type:resource-name:qualifier).

Is ARN customisable and persistent?

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