AZ-900 Practice Question 63: Elastic Scale Out in
Microsoft Azure Fundamentals (AZ-900) · Test 7 · question 3 of 10
An online ticket-sales platform automatically adds virtual machine instances when traffic spikes during an on-sale event, then automatically removes those instances once the spike subsides. No one resizes any individual virtual machine, and no administrator intervenes to add or remove the capacity by hand. Which concept describes this behavior?
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Answer:
Elasticity is the cloud benefit of scaling resources out as load increases and in when the extra capacity isn't needed, automatically and in response to real-time demand. The stem describes horizontal scaling, adding and removing whole VM instances, happening without a person resizing anything or triggering the change by hand, which is the defining trait of elastic scaling rather than a manually managed one.
Option A, vertical scaling, changes the specifications (CPU or RAM) of a single existing resource; the stem explicitly adds and removes whole instances instead of resizing one. Option B, high availability, is about uptime and SLA guarantees regardless of load; a service can be highly available while running a fixed amount of capacity that never changes. Option D, load balancing, distributes incoming traffic across the instances that already exist; it doesn't create or remove instances itself.
Reference: Describe the benefits of high availability and scalability in the cloud