Google Professional Cloud Network Engineer Question 728
Select 4Google Cloud PlatformYour organization has deployed a multi-tier application on Google Cloud using Compute Engine instances. Users report that they are unable to access the application. Upon investigation, you find that the frontend Compute Engine instances are not reachable over HTTP. You suspect a networking issue. Which of the following troubleshooting steps should you perform to resolve the issue?
- A
Verify that the firewall rules allow ingress traffic on port 80 to the frontend instances.
- B
Check the VPC subnet's route table to ensure the default internet route (0.0.0.0/0) is configured.
- C
Inspect the health status of the backend instances in the load balancer's health check.
- D
Ensure that the frontend instances have external IP addresses if they need to be accessed from the internet.
- E
Verify that the DNS record for the application points to the correct IP address.
Show answer and explanation
Correct answers: A, B, D, E
Explanation
To troubleshoot HTTP connectivity issues to the frontend Compute Engine instances, it is essential to verify the firewall rules, VPC routing, DNS configuration, and external IP availability. While health checks are important for load balancer functionality, they are not relevant for diagnosing direct connectivity issues to the frontend instances.
- A. Correct.
This is correct because a firewall rule must explicitly allow ingress traffic on port 80 for HTTP traffic to reach the instances.
- B. Correct.
This is correct because the default internet route (0.0.0.0/0) is necessary for the frontend instances to send and receive traffic to and from the internet.
- C. Incorrect.
This is incorrect because backend instance health checks are not relevant to frontend instance connectivity issues in this context.
- D. Correct.
This is correct because frontend instances need an external IP address if they are to be accessed directly from the internet.
- E. Correct.
This is correct because incorrect DNS configuration can prevent users from reaching the correct IP address of the application.