AZ-305 Question 154
Single answerA company plans to migrate a resource-intensive internal web application to Azure. The application experiences unpredictable traffic spikes and must remain available 24/7. The team wants to keep using virtual machines without refactoring the application code. They also want a strategy that allows automated scaling during surges and minimal downtime during maintenance. Which approach should you recommend to meet these requirements?
- A
Deploy a single Azure VM in an Availability Set and configure manual scaling.
- B
Deploy multiple Azure VMs behind a basic Load Balancer with manual VM additions.
- C
Implement an Azure Virtual Machine Scale Set with autoscaling, placing VMs behind an Azure Load Balancer.
- D
Use a single Azure VM in a dedicated host for increased resource allocation.
Show answer and explanation
Correct answer: C
Explanation
Azure Virtual Machine Scale Sets (VMSS) are recommended for workloads that demand high availability and can experience unexpected traffic spikes. By integrating VMSS with an Azure Load Balancer, you can automatically adjust the number of VM instances to match demand, ensuring minimal disruption during maintenance and handling surges effectively. According to Microsoft’s best practices, combining scale sets with load balancing simplifies large-scale VM deployments and helps maintain uptime (see Azure VM Scale Sets documentation).
- A. Incorrect.
Option 1 is incorrect because although an Availability Set helps distribute VMs across different fault domains, it does not provide automated scaling. Manual scaling for spike traffic would be less efficient and could cause downtime or performance bottlenecks.
- B. Incorrect.
Option 2 is a partial solution, but it still relies on manually adding or removing VMs behind the Load Balancer. This would not address unpredictable traffic surges in a timely manner, and manual scaling can introduce downtime or performance issues.
- C. Correct.
Option 3 is correct. Azure Virtual Machine Scale Sets combined with an Azure Load Balancer enable autoscaling for unpredictable spikes and distribute network traffic. This approach also streamlines maintenance by allowing new instances to be provisioned or updated with minimal downtime.
- D. Incorrect.
Option 4 is incorrect because a single VM in a dedicated host does not address scalability needs. A dedicated host can help with compliance or hardware isolation, but it won't provide the automated scaling or load balancing required for surges.