DOP-C02 Question 249
Select 2Your team manages a web application hosted on Amazon EC2 instances behind an Application Load Balancer (ALB). Recently, users have reported intermittent 5xx errors when accessing the application. You need to identify the root cause by analyzing relevant metrics and logs. Which of the following metrics or logs should you monitor to troubleshoot the issue effectively?
- A
ALB TargetResponseTime metric
- B
ALB HTTPCode_ELB_5XX_Count metric
- C
EC2 CPUUtilization metric
- D
RDS QueueDepth metric
- E
ALB access logs
Show answer and explanation
Correct answers: B, E
Explanation
To troubleshoot 5xx errors reported by users, it is critical to focus on metrics and logs directly related to the ALB and the application it serves. The ALB HTTPCode_ELB_5XX_Count metric highlights the occurrence of 5xx errors, while the ALB access logs provide detailed request and response data to identify patterns or specific causes. Metrics like TargetResponseTime, EC2 CPUUtilization, and RDS QueueDepth are useful for other performance-related analyses but do not directly address the issue of 5xx errors.
- A. Incorrect.
The ALB TargetResponseTime metric measures the time taken by the targets to respond to requests. While useful for identifying latency issues, it does not directly indicate 5xx errors.
- B. Correct.
The ALB HTTPCode_ELB_5XX_Count metric tracks the number of 5xx errors generated by the ALB. Monitoring this metric can help identify whether the load balancer is generating these errors.
- C. Incorrect.
The EC2 CPUUtilization metric monitors the CPU usage of your EC2 instances. While high CPU utilization could impact application performance, it does not directly indicate or relate to 5xx errors.
- D. Incorrect.
The RDS QueueDepth metric measures the number of outstanding I/O requests in the RDS instance. This metric is unrelated to 5xx errors generated by the ALB or application.
- E. Correct.
ALB access logs provide detailed information about each request, including HTTP status codes. They are essential for diagnosing the root cause of 5xx errors.