AWS Certified SysOps Administrator – Associate (legacy) — Question 748

A SysOps administrator is deploying a fleet of over 100 Amazon EC2 instances in an Amazon VPC. After the instances are set up and serving clients, a new DNS server needs to be added to the instances for DNS resolution.
What is the MOST efficient way to make this change?

Answer options

• A. Update the DHCP options set for the Amazon VPC.
• B. Use AWS OpsWorks to update the DNS server configuration for each instance.
• C. Use AWS Systems Manager to update the DMS server configuration for each instance.
• D. Write a script to update the DNS server configuration for each instance.

Correct answer: A

Explanation

Updating the DHCP options set for the Amazon VPC is the most efficient method because it automatically applies the new DNS configuration to all instances within the VPC without needing to access them individually. Options B, C, and D are less efficient because they require managing and executing configuration changes on each of the 100+ instances individually. Once the DHCP options set is updated, the EC2 instances will automatically receive the new DNS server details during their next DHCP renewal.