Which AWS service provides recommendations to help reduce costs, such as identifying idle EC2 instances, underutilized EBS volumes, and unassociated Elastic IPs?
AWS Trusted Advisor is an automated service that evaluates your AWS environment against best-practice checks across cost optimization, security, fault tolerance, performance, and service limits. For cost, it specifically detects idle and underutilized resources such as EC2 instances, EBS volumes, RDS databases, and load balancers, then recommends concrete actions like rightsizing, terminating, or purchasing Reserved Instances and Savings Plans. This makes it the correct tool because it proactively surfaces optimization opportunities for existing deployed workloads.
Why this answer
AWS Trusted Advisor is the correct service because it provides automated cost optimization recommendations by analyzing your AWS environment. It specifically identifies idle EC2 instances, underutilized EBS volumes, and unassociated Elastic IPs, which are common sources of wasted spend. These checks are part of the cost optimization category within Trusted Advisor, and they help you reduce costs by right-sizing or releasing unused resources.
Exam trap
The trap here is that candidates often confuse AWS Cost Explorer (which shows cost data) with Trusted Advisor (which provides actionable recommendations), leading them to choose Cost Explorer because it sounds cost-related, but it lacks the specific idle resource detection logic.
How to eliminate wrong answers
Option A is wrong because AWS Cost Explorer is a tool for visualizing, understanding, and managing your AWS costs and usage over time, but it does not proactively identify idle resources or provide specific recommendations like Trusted Advisor does. Option C is wrong because Amazon CloudWatch is a monitoring service for metrics, logs, and alarms; it can track utilization but lacks built-in cost optimization checks for idle EC2 instances or unassociated Elastic IPs. Option D is wrong because AWS Pricing Calculator is a planning tool used to estimate costs for new architectures or migrations, not a service that analyzes existing resources to identify waste or provide recommendations.