We are trying to expand our reliability setup using VPC in us-west-1. The 'a' and 'b' AZs work fine, but when I try to create subnets on 'c' it just fails with the message:
Value (us-west-1c) for parameter availabilityZone is invalid.
Subnets can currently only be created in the following availability zones:
us-west-1b, us-west-1a.
Is this a transient failure or are there just only two VPC-enabled AZs in that region? If the latter, is there a list somewhere with how many AZs in each region are VPC-enabled?
Best Answer
As Availability Zones grow over time, Amazon's ability to expand them can become constrained. If this happens, they might restrict you from launching an instance in a constrained Availability Zone unless you already have an instance in that Availability Zone. Therefore, your account might have a different number of available Availability Zones in a region than another account.
Use the describe-availability-zones command to describe your Availability Zones within the region.