Choosing EC2 Purchase Options for Uninterruptible Bursts
Short answer
B Use On-Demand Instances to handle short bursts of work that cannot be interrupted.
Question
Key Takeaways
The core trap is confusing 'variable' workloads (which often suggest Spot Instances) with 'cannot stop' requirements, which strictly prohibit interruptions found in Spot or Savings Plans.
This question evaluates the selection of Amazon EC2 pricing models based on workload predictability and interruption tolerance. The correct answer is On-Demand Instances because they guarantee availability without interruption risks.
Common mistake: Candidates often select Spot Instances (A) because the workload is described as variable and temporary, failing to notice the critical constraint that instances cannot be interrupted.
Expert Analysis
Why the Answer Is Correct
On-Demand Instances are the only option that provides immediate capacity without long-term commitment and guarantees no interruption. Since the requirement states the workload "cannot stop before finishing," any model that allows AWS to reclaim resources (like Spot) or requires upfront payment commitments (like Savings Plans/Reserved) is unsuitable.
Why the Other Options Are Wrong
Spot Instances (A) offer significant discounts but can be terminated by AWS with a two-minute warning, violating the 'cannot stop' rule. Savings Plans (C) and Reserved Instances (D) require one- or three-year commitments and are designed for steady-state, predictable workloads, not short bursts. They also do not inherently prevent termination if the instance type becomes unavailable, though this is less common than Spot termination.
Community Comment Notes
The community consensus strongly supports Option B. As user AravindrajG noted, the key phrase is "short bursts of work that cannot stop before finishing," which directly points to the reliability of On-Demand Instances. Other users like ShaiTay confirmed that the inability to interrupt is the deciding factor against cheaper options.
Exam Strategy
Always read the full description of the workload's constraints. If the keyword 'cannot stop', 'interruption-sensitive', or 'critical' appears, eliminate Spot Instances immediately. For short-term, unpredictable needs where cost is secondary to availability, choose On-Demand.
Frequently Asked Questions
Why are Spot Instances wrong for variable workloads here?
Can Savings Plans be used for short bursts?
Community Votes
100% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 4 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 4
-
AravindrajG 👍 2 Answered BKeyword: short bursts of work that cannot stop before finishing. Answer is B. On-demand Instances
-
Meow7 👍 1B is correct. Need help with discussion on 549 551 ~ 562. Thanks.
-
Nethach 👍 1B is correct "cannot stop before finishing"
-
ShaiTay 👍 1 Answered BB. On-Demand Instances
Reader comments & corrections
No reader corrections yet — spotted an error or have a note? Share it below.
Related Analysis
Practice All CLF-C02 Questions
Access 120 questions with complete answers and detailed explanations.
View Full CLF-C02 Practice Test →