Dynamic Provisioning Aspects for Availability Zones in CloudFormation Template
Question
You are creating a Cloudformation template that will be used to automate the provisioning of VPC's and Subnets.
You need to allow for dynamic provisioning aspects as to which Availability zone the subnet needs to be created.
Which part of the template would help in provisioning such dynamic values?
Answers
Explanations
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A. B. C. D.Answer - A.
This is also provided in the AWS Documentation.
Parameters.
"Use the optional Parameters section to customize your templates.
Parameters enable you to input custom values to your template each time you create or update a stack".
Option B is invalid since this is used to specify the Output values of a template.
Option C is invalid since this is used to specify additional tags for the template.
Option D is invalid since this is used to specify changes in a CloudFormation template.
For more information on Cloudformation parameters, please visit the below link.
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/parameters-section-structure.htmlThe correct answer is A. Parameters.
A CloudFormation template is a declarative language for describing AWS resources and their dependencies. The Parameters section of the template allows you to define input values that can be passed to the CloudFormation stack during creation or update. These input values can be used to make the template dynamic and flexible.
In this scenario, you can create a parameter for the availability zone where the subnet will be created. For example:
json"Parameters" : { "AvailabilityZone" : { "Description" : "The availability zone for the subnet", "Type" : "AWS::EC2::AvailabilityZone::Name" } } This parameter will allow the user to specify the availability zone where the subnet needs to be created. You can then use this parameter to dynamically provision the subnet in the specified availability zone using the Fn::Select function. For example:
json"Resources" : { "Subnet" : { "Type" : "AWS::EC2::Subnet", "Properties" : { "VpcId" : { "Ref" : "Vpc" }, "AvailabilityZone" : { "Fn::Select" : [ "0", { "Fn::GetAZs" : { "Ref" : "AvailabilityZone" } } ] } } } } In this example, the Fn::GetAZs function returns a list of availability zones for the specified region. The Fn::Select function then selects the first availability zone in the list, which corresponds to the value of the AvailabilityZone parameter. This value is then used to set the AvailabilityZone property of the subnet resource.
Output, Tags, and Change Sets are not relevant to this scenario. Output is used to export values from the stack, Tags are used to apply metadata to resources, and Change Sets are used to preview and manage changes to the stack.
