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

The `disk_io_time` metric, collected by the CloudWatch agent on EC2 Linux instances, measures the total time (in milliseconds) that read and write requests have waited on I/O, helping to assess disk performance for instance sizing. The WGU Cloud Deployment and Operations Study Guide (Section 4.1, CloudWatch Agent Metrics) states, "The `disk_io_time` metric, available via the CloudWatch agent, tracks the time spent waiting for I/O operations, providing insight into disk contention for optimizing EC2 instance sizing." disk_read_ops, diskio_reads, and diskio_read_bytes measure operation counts or bytes, not wait times.

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The Reachability Analyzer in AWS VPC should be used to troubleshoot connectivity issues from on-premises computers to EC2 instances, especially when a network security group (NSG) is suspected. It analyzes the network path and identifies blocked traffic due to NSG rules or route tables. The WGU Cloud Deployment and Operations Study Guide (Section 3.2, VPC Troubleshooting) states, "Reachability Analyzer helps diagnose connectivity issues by simulating traffic paths, identifying if an NSG rule (e.g., blocked port) or route table is causing the problem from on-premises to EC2 public IPs." Flow Logs provide data but not analysis, PrivateLink is for private connections, and Traffic Mirroring is for monitoring.

Amazon CloudWatch alarms can trigger notifications when a metric breaches a defined threshold. The AWS solution designed to send emails based on these alarms is Amazon Simple Notification Service (SNS). SNS supports sending notifications via email, SMS, and other protocols when subscribed endpoints are triggered by CloudWatch alarms. The WGU Cloud Deployment and Operations Study Guide (Section 4.3, Monitoring and Alarms) states that SNS is the primary service for delivering notifications from CloudWatch, allowing users to configure emailsubscriptions for alarm states. Other options like SQS, Amplify, and Kinesis are not designed for this purpose.