SAA-C03 Question 136
Select 3A company is designing a web application using a multi-tier architecture on AWS. The architecture consists of a front-end layer, an application layer, and a database layer. The front-end is hosted on Amazon EC2 instances behind an Elastic Load Balancer (ELB). The application layer is also hosted on EC2 instances and communicates with the database layer, which uses Amazon RDS. The company needs to ensure that the application is highly available, scalable, and secure. Which combination of actions should be taken to meet these requirements?
- A
Use Auto Scaling groups for EC2 instances in both the front-end and application layers.
- B
Place the EC2 instances in a single Availability Zone to minimize latency.
- C
Configure a security group to allow only the required ports between the front-end, application, and database layers.
- D
Enable Multi-AZ deployment for the Amazon RDS database.
- E
Install a single EC2 instance as a bastion host and allow SSH access from the public internet.
Show answer and explanation
Correct answers: A, C, D
Explanation
A multi-tier architecture on AWS requires proper configuration to ensure high availability, scalability, and security. Auto Scaling groups improve scalability and fault tolerance for the front-end and application layers. Security groups must be configured to restrict access between layers to only the necessary ports, maintaining security. Amazon RDS with Multi-AZ deployment ensures high availability for the database layer by providing failover capability. Placing resources in a single Availability Zone or relying on a single bastion host introduces risks to availability and security.
- A. Correct.
Using Auto Scaling groups ensures that both the front-end and application layers can automatically scale based on demand, improving scalability and availability.
- B. Incorrect.
Placing EC2 instances in a single Availability Zone reduces redundancy and availability, which goes against the principles of high availability.
- C. Correct.
Configuring security groups to allow only the required ports ensures secure communication between the different layers of the architecture.
- D. Correct.
Enabling Multi-AZ deployment for Amazon RDS provides high availability and automatic failover in case of an Availability Zone failure.
- E. Incorrect.
Using a single bastion host with SSH access from the public internet creates a potential security risk and is not recommended as a best practice.