Question 520 of 1,024
Cloud ConceptshardMultiple ChoiceObjective-mapped

How to Automatically Recover from Failure in AWS?

This CLF-C02 practice question tests your understanding of cloud concepts. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A company is designing a resilient multi-tier web application on AWS. The architect wants to implement the Well-Architected Framework Reliability pillar design principle of 'automatically recover from failure.' Which combination of services implements this most completely?

Quick Answer

The answer is EC2 Auto Scaling, ELB health checks, and RDS Multi-AZ working together. This combination most completely implements the Well-Architected Reliability pillar principle of automatically recovering from failure because it creates a self-healing architecture across both compute and database tiers: Auto Scaling replaces failed EC2 instances automatically, ELB health checks detect unhealthy targets and reroute traffic, and RDS Multi-AZ provides automatic database failover to a standby in another Availability Zone. On the AWS Certified Cloud Practitioner CLF-C02 exam, this question tests your understanding that true automatic recovery requires orchestrated services, not just one—a common trap is choosing only Auto Scaling or only Multi-AZ, missing the layered approach. For the search intent "automatically recover from failure aws services," remember that AWS defines recovery as a combination of detection, traffic redirection, and replacement. A useful memory tip is "Triple-A Recovery": Auto Scaling, ALB/ELB health checks, and AZ failover for RDS.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

EC2 Auto Scaling + ELB health checks + RDS Multi-AZ

Option B is correct because it combines EC2 Auto Scaling to automatically replace unhealthy instances, ELB health checks to detect failures and route traffic away from them, and RDS Multi-AZ to automatically failover to a standby database in a different Availability Zone. This trio directly implements the 'automatically recover from failure' principle by enabling self-healing at both the compute and database tiers without manual intervention.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • Manual restart procedures documented in a runbook

    Why it's wrong here

    Manual procedures don't implement automatic recovery — they require human intervention and increase recovery time.

  • EC2 Auto Scaling + ELB health checks + RDS Multi-AZ

    Why this is correct

    Auto Scaling automatically replaces failed instances, ELB health checks remove unhealthy targets from rotation, and RDS Multi-AZ automatically fails over the database — full automatic recovery without human intervention.

    Related concept

    Read the scenario before looking for a memorised answer.

  • AWS CloudTrail + Amazon CloudWatch

    Why it's wrong here

    CloudTrail and CloudWatch provide logging and alerting — they detect failures but don't automatically recover from them.

  • AWS Config rules with manual remediation

    Why it's wrong here

    Config rules detect configuration drift — manual remediation doesn't implement automatic recovery.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often confuse monitoring services (like CloudTrail and CloudWatch) with recovery services, failing to recognize that detection alone does not satisfy the 'automatically recover' principle unless paired with an automated action mechanism such as Auto Scaling or Multi-AZ failover.

Detailed technical explanation

How to think about this question

Under the hood, ELB health checks use TCP or HTTP health probes at configurable intervals (e.g., every 10 seconds) to determine instance health; when an instance fails consecutive checks, the load balancer stops routing traffic to it and Auto Scaling triggers a scale-in event to terminate the unhealthy instance and launch a new one. For RDS Multi-AZ, synchronous replication to the standby instance occurs at the storage layer, and failover is automatically initiated by Amazon's DNS-based routing within 60–120 seconds, with no changes needed to the application connection string. This layered recovery approach ensures that even if an entire Availability Zone fails, the application remains available with minimal downtime.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this CLF-C02 question test?

Cloud Concepts — This question tests Cloud Concepts — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: EC2 Auto Scaling + ELB health checks + RDS Multi-AZ — Option B is correct because it combines EC2 Auto Scaling to automatically replace unhealthy instances, ELB health checks to detect failures and route traffic away from them, and RDS Multi-AZ to automatically failover to a standby database in a different Availability Zone. This trio directly implements the 'automatically recover from failure' principle by enabling self-healing at both the compute and database tiers without manual intervention.

What should I do if I get this CLF-C02 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 11, 2026

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This CLF-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CLF-C02 exam.