AWS Certified SysOps Administrator Practice Exam

When deploying a full LAMP stack with CloudFormation, why might the stack creation fail?

1. The EC2 instance is not properly sized

2. The application does not have enough permissions

3. The subnet lacks a network route to the CloudFormation service

4. The script is deprecated and no longer works

The correct answer is: The subnet lacks a network route to the CloudFormation service

When deploying a full LAMP (Linux, Apache, MySQL, PHP) stack using AWS CloudFormation, the successful creation of the stack relies on various elements working in tandem. In this scenario, the correct reason for a potential failure in stack creation is due to the subnet lacking a network route to the CloudFormation service. CloudFormation requires a proper network configuration to communicate effectively with AWS services. If the subnet where the resources are being provisioned does not have appropriate routing and access to the necessary endpoints, the provisioning process cannot proceed, leading to stack creation failure. For example, if there is no route to the VPC endpoint that connects to necessary services such as EC2 or S3, CloudFormation cannot execute the required actions, such as creating and configuring instances, setting up security groups, or downloading resources. Without this connectivity, any attempts to launch resources or deploy applications would result in errors, indicating that the stack creation cannot complete successfully. This networking aspect is critical in environments that might be isolated or configured with strict security rules, and addressing such routing issues is vital for successful deployments using CloudFormation.