AWS AMIs list

https://cloud-images.ubuntu.com/locator/ec2/   - to find the AMI IDs of the images.


Every Region has different AMI IDs, US-West-1, US-East-1, etc..

So when you use Terraform code to spin up your instances, you have to be careful in selecting the AMI IDs.
Otherwise it will throw errors.

References:
Good to Read thoroughly:
https://www.safaribooksonline.com/library/view/terraform-up-and/9781491977071/ch04.html

https://docs.docker.com/engine/userguide/labels-custom-metadata/#key-format-recommendations