AWS ap-northeast-1に4個のAZがあることを確認する (ap-northeast-1dができた) ref: https://qiita.com/tnir/items/7ac06bf5f3974477e09f

file0.txt

$ aws ec2 describe-availability-zones --output text
AVAILABILITYZONES   ap-northeast-1  available   ap-northeast-1a
AVAILABILITYZONES   ap-northeast-1  available   ap-northeast-1c
AVAILABILITYZONES   ap-northeast-1  available   ap-northeast-1d

file1.txt

$ aws ec2 describe-availability-zones --output text
AVAILABILITYZONES   ap-northeast-1  available   ap-northeast-1a
AVAILABILITYZONES   ap-northeast-1  available   ap-northeast-1b
AVAILABILITYZONES   ap-northeast-1  available   ap-northeast-1c
AVAILABILITYZONES   ap-northeast-1  available   ap-northeast-1d

file2.txt

$ aws ec2 describe-availability-zones --output text

Could not connect to the endpoint URL: "https://ec2.ap-norheast-1.amazonaws.com/"