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AWS Certified Solutions Architect - Associate Exam Question Walkthrough
Struggling with AWS exam questions? This post breaks down a key question about EC2 instance management for SAA-C03.
A common pitfall for candidates is understanding how to maintain application availability and resilience in AWS. This question tests your knowledge of EC2 instance management and the services that ensure operational continuity.
The question
A fleet of EC2 instances must automatically replace unhealthy instances and maintain capacity across multiple AZs. Which service provides this?
- A. AWS Auto Scaling group spanning multiple AZs
- B. A single On-Demand instance
- C. Elastic IP addresses
- D. An S3 lifecycle policy
Think before you scroll
Consider the functionality needed to automatically manage EC2 instances in a resilient architecture. Pay attention to the requirements of replacing unhealthy instances and maintaining capacity across multiple Availability Zones (AZs).
The answer
The correct option is A. AWS Auto Scaling group spanning multiple AZs. An Auto Scaling group can perform health checks, automatically replace unhealthy instances, and maintain capacity across multiple AZs, which is essential for resilience.
Why the other options lose
- B. A single On-Demand instance: This option does not support automatic replacement of instances. If the instance fails, it won't recover or scale, violating the requirement for maintaining capacity and resilience.
- C. Elastic IP addresses: Elastic IPs are used for static IP addresses but do not provide any health-checking or automatic replacement features for EC2 instances. They are not relevant to the question's context.
- D. An S3 lifecycle policy: This option pertains to managing objects in S3 storage, including transitioning or deleting objects based on rules. It does not relate to EC2 instance management or maintaining capacity.
The concept behind it
The principle at play here is the importance of resilience in cloud architectures. An Auto Scaling group ensures that your application can adjust its capacity based on demand and health of the instances. It automatically replaces unhealthy instances to maintain the desired capacity, which is critical for high availability.
Exam trap to remember
Always remember: when asked about maintaining instance health and capacity across multiple AZs, think Auto Scaling. It’s your go-to service for resilience in EC2 architectures.