W3010 AWS::EC2::Volume requires hardcoded AvailabilityZone

cfn-lint version: (cfn-lint --version) 0.20.0

Description of issue. Creating additional volumes require AvailabilityZone as a mandatory property.

Please provide as much information as possible: When creating additional volumes to be associated with an instance, there is a requirement to add the AvailabilityZone as a mandatory property.

AvailabilityZone The Availability Zone in which to create the new volume. Required: Yes Type: String

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-ebs-volume.html

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[kddejong]

If you are associating to an instance you can use the instance attribute too.

VolumeGetAz:
    Type: "AWS::EC2::Volume"
    Properties:
      AvailabilityZone:  !GetAtt EC2Instance.AvailabilityZone

[fatbasstard]

The rule is there to prevent you from hardcoding AZ’s, making going multi-region more complex.

In this an AZ is indeed needed, but it’s about how to specify this. Never “lock” it to a region/AZ in the template itself, but use parameters or intrinsic function (or something else) so the template can be deployed to other regions.

Example

AWSTemplateFormatVersion: "2010-09-09"
Parameters:
  AvailabilityZone1a:
    Type: "AWS::EC2::AvailabilityZone::Name"
    Default: "us-east-1a"
Resources:
  VolumeHardcoded:
    Type: "AWS::EC2::Volume"
    Properties:
      AvailabilityZone: "us-east-1a" # Hardcoded
  VolumeParameter:
    Type: "AWS::EC2::Volume"
    Properties:
      AvailabilityZone: !Ref "AvailabilityZone1a"
  VolumeGetAz:
    Type: "AWS::EC2::Volume"
    Properties:
      AvailabilityZone: !Select
        - 0
        - Fn::GetAZs: !Ref 'AWS::Region'

In this template, only the first one (hardcoded one) generated an error (The W3010 warning in this case). The other 2 are “dynamic” ways of specifying the AZ.