[Error Reporting] AWS EFS Service is not available in this region

[aakash-garg-olx]

Hi there,

I have created the module to launch EFS, it was created successfully in Ireland Region eu-west-1, but when I tried to use the same in Singapore Region ap-southeast-1, it started creating EFS and went in the loop, as AWS EFS Service is still not available in Singapore Region.

So, I think it would be good if you throw the error like Service is not available in this region then it would be better as it appears that it is creating EFS, but actually it is not. It gets confusing sometimes.

[Ninir]

Hi @aakash-garg-olx,

As @radeksimko explained it for a slightly different case but very related:

this is unfortunately a side effect of how AWS launches services into regions. Each endpoint is region-specific, e.g. email.us-west-2.amazonaws.com for us-west-2. The underlying SDK maps passed region to the appropriate endpoint hostname.

The reason Terraform let you wait is because it assumes the DNS is temporarily failing to resolve the hostname - which may be the case in some environments. Reducing DNS resolution timeout is a theoretical option here, but this would also affect users which have genuine temporary DNS failures so this may not be practical.

Neither Terraform or the underlying AWS SDK have knowledge of what regions are supported at any given time because this does change quite often. Maintaining a list of supported regions for every service while updating it every time AWS decides to launch a service into a new region would cause (IMO) unreasonable maintenance burden.

We however apply this approach to regions themselves to avoid the same issue if user has a typo in region name by maintaining a static list of regions. This was criticised in the past by some users questioning the reason for maintaining a static list, but I still believe it's ok to do it, because whole new regions aren't introduced every day or month, so the maintenance burden is fairly low. Secondly the chance of making a typo is high enough so the benefit of having static validation is justified and overweights the cons.

Sorry for the confusion coming from this behaviour, I hope the explanation makes sense.

For that reason we can't really help on anything here :-/

I'm now going to close this one if you don't mind. Tell me if you have any inputs that would help here, thanks!

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!