[Solved] creating EC2 Subnet: InvalidParameterValue: Value (us-east-2b) for parameter availabilityZone is invalid. Subnets can currently only be created in the following availability zones: us-east-1a, us-east-1b, us-east-1c, us-east-1d, us-east-1e, us-east-1f.

 Issue:-

While creating the multiple region vpc through the terraform getting the error during terraform apply when it tries to create the subnets in 2nd vpc.

Error:-

 module.vpc2.aws_subnet.public[0]: Creating...  
 ╷  
 │ Error: creating EC2 Subnet: InvalidParameterValue: Value (us-west-2b) for parameter availabilityZone is invalid. Subnets can currently only be created in the following availability zones: us-east-1a, us-east-1b, us-east-1c, us-east-1d, us-east-1e, us-east-1f.  
 │      status code: 400, request id: 79a19b0b-93d1-4a78-9c0c-124e429c78de  
 │   
 │  with module.vpc2.aws_subnet.public[1],  
 │  on .terraform/modules/vpc2/main.tf line 359, in resource "aws_subnet" "public":  
 │ 359: resource "aws_subnet" "public" {  

 

Cause:-

Even though i mentioned the providers still the terraform was trying to create the us-west-2b subnet in the wrong region i.e. us-east-1 and it was not able to find those subnets and thats why aws is throughing the error that only us-east-1a, us-east-1b, us-east-1c, us-east-1d, us-east-1e, us-east-1f subnets are available to create the subnets.

Solution:-

Solution is to provider the multiple providers as

 provider "aws" {  
  region = "us-east-1"  
 }  
 module "vpc1" {  
  providers = { aws = aws }  
  source = "terraform-aws-modules/vpc/aws" 

 provider "aws" {  
  alias = "secondary"  
  region = "us-west-2"  
 }  
 module "vpc2" {  
  providers = { aws = aws.secondary }  
  source = "terraform-aws-modules/vpc/aws" 

Once you mention the providers like i have done above than the terraform would pick the multiple regions and wont through the error mentioned above and that should solve the issue.