Which template coding mistakes could have caused this failure?
(Choose two.)
The developer’s template does not use the Ref intrinsic function to refer to the subnets.
The developer’s template does not use the ImportValue intrinsic function to refer to the subnets.
The Mappings section of the developer’s template does not refer to the subnets.
The network team’s template does not export the subnets in the Outputs section.
The network team’s template does not export the subnets in the Mappings section.
Explanations:
The Ref intrinsic function is used to reference resources within the same template. Since the subnets are created in a separate template, the developer’s template cannot use Ref to refer to them.
The ImportValue intrinsic function is necessary to reference resources (like subnets) that are exported from another CloudFormation stack. If the developer’s template does not use ImportValue to refer to the subnets created by the network team, the stack launch will fail.
The Mappings section is used for defining key-value pairs and does not apply to referencing resources from another stack. Therefore, it is not relevant in this context.
For the developer’s template to successfully reference the subnets created by the network team’s template, those subnets must be exported in the Outputs section. If they are not exported, the developer cannot access them using ImportValue.
The Mappings section is not used for exporting resources. Outputs must be defined in the Outputs section for resources to be shared between templates, so this option is irrelevant to the issue at hand.
I rate that the answer is:
The developer’s template does not use the ImportValue intrinsic function to refer to the subnets.