How Do You Troubleshoot the AWS Error “Subnets specified must be in at least two different AZs”?

Problem scenario
You run an AWS CLI command, but you get this error message:
"An error occurred (InvalidParameterException) when calling the CreateCluster operation: Subnets specified must be in at least two different AZs"
How do you find subnets in different availability zones?

Solution
Run commands such as these (but replace the "us-west-x" and "us-east-x" with the availability zones that you use):

aws ec2 describe-subnets --query 'Subnets[?AvailabilityZone==us-west-1a]'
aws ec2 describe-subnets --query 'Subnets[?AvailabilityZone==us-west-1b]'
aws ec2 describe-subnets --query 'Subnets[?AvailabilityZone==us-west-1c]'
aws ec2 describe-subnets --query 'Subnets[?AvailabilityZone==us-east-2a]'
aws ec2 describe-subnets --query 'Subnets[?AvailabilityZone==us-east-2b]'
aws ec2 describe-subnets --query 'Subnets[?AvailabilityZone==us-east-2c]'

Now you will see more subnet IDs for your original command. You can supply that original command accordingly and re-run it successfully.

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