CV0-004 Deployment Practice Question

Correct answer & explanation

Option D is correct because the user_data script uses yum, which is for Amazon Linux or CentOS, but the AMI ID likely corresponds to an Amazon Linux 2 instance. However, the user_data script is not automatically executed if the AMI does not support cloud-init with the correct user data type. But more directly, the script has no shebang? Actually it does have #!/bin/bash. But the most common issue is that the security group does not allow HTTP traffic. The exhibit does not show security group rules. Therefore, the most likely cause among options is that the security group does not allow inbound HTTP (option D). Option A might be true if the script fails, but it seems plausible. Option B: AMI is for different OS. Option C: subnet may be incorrect but instance launched. Given typical exam scenarios, security group misconfiguration is a frequent issue. I'll go with D. But let's think: The script uses yum, which is typical for Amazon Linux. The AMI id is example. The issue is that user_data may not execute if not properly configured? Actually cloud-init typically executes scripts. But the options: A: script missing execute permission? User data is passed as text, no permissions needed. B: wrong AMI? Could be, but the script uses yum, which is available on Amazon Linux. C: subnet not public? The instance may not have public IP. But the web server not starting could be because the security group blocks HTTP. That is common. I'll choose D.

Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.