A CloudOps engineer is examining the following AWS CloudFormation template: Why will the stack creation fail?

The correct answer is C. The PrivateDnsName cannot be sot from a CloudFormation template. In AWS CloudFormation, the PrivateDnsName property of an AWS::EC2::Instance resource is a read-only attribute automatically assigned by AWS when the instance is launched. It cannot be manually specified in the template. Attempting to define it causes stack creation to fail with…

Submitted by rohit_dlh· Mar 5, 2026Deployment, provisioning, and automation

Question

A CloudOps engineer is examining the following AWS CloudFormation template:

Why will the stack creation fail?

Exhibit

Options

AThe Outputs section of the CloudFormation template was omitted.
BThe Parameters section of the CloudFormation template was omitted.
CThe PrivateDnsName cannot be sot from a CloudFormation template.
DThe VPC was not specified in the CloudFormation template.

How the community answered

(36 responses)

A
11% (4)
B
3% (1)
C
81% (29)
D
6% (2)

Explanation

In AWS CloudFormation, the PrivateDnsName property of an AWS::EC2::Instance resource is a read-only attribute automatically assigned by AWS when the instance is launched. It cannot be manually specified in the template. Attempting to define it causes stack creation to fail with a validation error. CloudFormation manages this value based on the subnet and VPC DNS configuration, so it must be omitted from the template.

Topics

#CloudFormation#PrivateDnsName#template limitations#stack creation

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