Cloud-Deployment-and-Operations Exam Dumps : WGUCloud Deployment and Operations

Elastic Load Balancing (ELB) should be used to horizontally scale Amazon EC2 instances by distributing incoming traffic across multiple instances, improving availability and fault tolerance. ELB works in conjunction with Auto Scaling groups to add or remove instances based on demand. The WGU Cloud Deployment and Operations Study Guide (Section 3.2, Elastic Load Balancing) notes, "Elastic Load Balancing distributes traffic across EC2 instances, enabling horizontal scaling as part of an Auto Scaling group to handle increased load efficiently." Elastic IPs, elastic network interfaces, and Elastic Beanstalk do not provide this scaling functionality.

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CloudWatch should be used to identify and shut down idle EC2 instances by monitoring metrics such as CPU utilization or network activity. Custom alarms can be set to trigger an AWS Lambda function or Systems Manager automation to terminate idle instances, optimizing costs. The WGU Cloud Deployment and Operations Study Guide (Section 4.1, CloudWatch Metrics) states, "CloudWatch can monitor EC2 instance metrics like CPUUtilization; an alarm can be configured to invoke a Lambda function to terminate idle instances, ensuring cost efficiency." CloudFront, CloudSearch, and CloudTrail are not designed for this monitoring and automation task.

The `Ref` function in an AWS CloudFormation template is used to obtain values of components defined within the template, such as resource IDs, parameters, or outputs. This function allows dynamic referencing of resources during stack creation. The WGU Cloud Deployment and Operations Study Guide (Section 5.3, CloudFormation Functions) states, "The `Ref` function is used to reference the logical IDs of resources, parameters, or mappings defined in the template, enabling dynamic value retrieval (e.g., `Ref: MyEC2Instance` returns the instance ID)." ImportValue is used for cross-stack references, Cidr for IP range calculations, and GetAZs for availability zone lists, making them unsuitable here.