Question #1603
A company is deploying a mission-critical application on Amazon EC2 instances that require high fault tolerance. The architecture must ensure that each instance is placed on distinct underlying hardware to minimize the risk of simultaneous failures. Which networking configuration should be used?
Deploy the EC2 instances in a spread placement group.
Distribute the EC2 instances across multiple AWS Regions.
Configure the EC2 instances with dedicated tenancy.
Launch the EC2 instances in a cluster placement group.
Explanation
Answer A is correct because spread placement groups distribute EC2 instances across distinct underlying hardware racks within an Availability Zone (AZ). This isolation reduces the risk of correlated failures, making it ideal for mission-critical applications requiring high fault tolerance.
Why other options are incorrect:
- B (Multiple Regions): While distributing across regions improves disaster recovery, the question focuses on fault tolerance within a single architecture, not cross-region redundancy.
- C (Dedicated Tenancy): Dedicated tenancy ensures instances run on single-tenant hardware but does not guarantee placement on separate physical hardware racks.
- D (Cluster Placement Group): Cluster placement groups optimize for low-latency performance by grouping instances on the same hardware, increasing the risk of simultaneous failures.
Key Points:
- Spread Placement Groups: Best for fault tolerance by isolating instances.
- Cluster Placement Groups: Best for high-performance computing (HPC) with low latency.
- Dedicated Tenancy: Ensures hardware isolation from other AWS customers, not fault tolerance.
- Multi-Region: Used for disaster recovery, not intra-region fault tolerance.
Answer
The correct answer is: A