(langfuse-deploy) Langfuse deployment failing in ap-northeast-2 Seoul #606
Description
As identified by @raphael-shin in this PR, deployment of the Langfuse CDK solution fails in Seoul because it tries to use an Availability Zone that isn't supported by CloudFront VPC Origins.
Unfortunately though, by my testing the original proposed fix doesn't work properly: stack.availabilityZones returns AZ names (e.g. ap-northeast-2a), whereas support is defined by AZ ID (excluding apne2-az1).
As detailed here, 9 older AWS Regions map AZ IDs to different names per AWS Account - while all newer Regions have a global 1:1 ID-Name mapping. We can't really ignore this complexity because 3 (but not all) of the CloudFront-restricted regions are in that older list (Virginia, California, Tokyo).
As a result we're probably also at risk of intermittent deployment failures also in California, Tokyo, and (less likely because of the higher AZs-to-unsupported-AZs ratio) Virginia - depending on the target AWS Account's internal AZ ID-name mapping, assuming CDK defaults to AZs 'a' and 'b'. Seoul I expect is probably always failing since it's az1 that's unsupported, presumably the deterministic mapping names that 'a', and presumably CDK Vpc's default 2-AZ selection is 'a' and 'b'.