220-1101 Question 380
Single answerElasticityA small company hosts its customer portal in a public cloud environment. During normal business hours, usage is low, but traffic spikes sharply when the company sends marketing emails. The IT technician notices the portal becomes slow during these spikes, while the company is also paying for more compute resources than it needs overnight. Which cloud characteristic would best address both the performance issue during peak demand and the wasted cost during low demand?
- A
Elasticity, so resources can automatically scale out during spikes and scale back during low usage
- B
High availability, so the application remains online by duplicating systems across multiple hosts
- C
Measured service, so cloud usage can be monitored and billed based on consumption
- D
Rapid elasticity of local workstation hardware, so employee PCs can share spare CPU capacity with the portal
Show answer and explanation
Correct answer: A
Explanation
The best answer is elasticity because it is the cloud characteristic that allows resources to automatically scale in response to workload changes. In practical terms, this lets an organization provision more compute instances, memory, or other resources when demand rises and release them when demand falls. This prevents poor performance during spikes and reduces the expense of leaving excess capacity running all the time. By contrast, high availability is about uptime and redundancy, and measured service is about tracking and billing resource consumption. NIST's widely referenced cloud computing guidance describes rapid elasticity as a core cloud characteristic, meaning capabilities can be elastically provisioned and released to scale with demand. For A+ Core 1, candidates should recognize elasticity as the feature that supports burst workloads efficiently in real-world cloud deployments.
- A. Correct.
Correct. Elasticity in cloud computing means resources can be dynamically increased or decreased based on workload demand. In this scenario, the portal needs additional compute capacity during marketing-driven traffic spikes and fewer resources overnight. Elasticity directly addresses both the performance problem and the unnecessary cost of overprovisioning.
- B. Incorrect.
Incorrect. High availability focuses on minimizing downtime and improving fault tolerance, such as through redundancy or failover. While that can help keep a service online if a host fails, it does not specifically solve the problem of scaling resources up during busy periods and down during quiet periods to control costs.
- C. Incorrect.
Incorrect. Measured service is a cloud characteristic that tracks usage for billing and reporting purposes. It helps the company understand consumption and cost, but by itself it does not automatically add or remove compute resources to handle changing demand. Someone might choose this because the scenario mentions wasted cost, but the core issue is dynamic resource adjustment.
- D. Incorrect.
Incorrect. This is not a valid cloud elasticity solution. Employee workstations are not typically used to provide production cloud compute for a public-facing portal in an A+ cloud-computing context. The phrase 'rapid elasticity of local workstation hardware' misapplies the concept and describes an impractical and unsupported approach.