AWS Compute Optimizer analyzes your current EC2 instance usage and recommends the most cost-effective instance type. In this case, the current instance may not have enough CPU capacity, so scaling vertically (upgrading to a larger instance type) could provide immediate relief from the 100% CPU utilization.

The question asks for a combination of steps, meaning the selected answers should work together to form a complete solution rather than being two independent actions. B - prepared the instance for the scaling E - Implement Auto Scaling for performance improvement and high availability

The answer is A and E. A for adding more CPU (Vertical scaling ) and E for adding more Servers (Horizontal scaling)

The question talk about a "combination of steps" then IMO answer is BE. BE are steps of a solution that resolve performance issue and improve application availability. D is for improve the solution : https://docs.aws.amazon.com/compute-optimizer/latest/ug/view-asg-recommendations.html A is a solution (not a step) but it is not the most cost effective C is wrong: autoscaling and ALB are horizontal scaling

Since options C and D are irrelevant, let's disregard them. That leaves us with ABE. B is a prerequisite for E, so you cannot have E with B. AB will be two disjointed choices. So you have to choose B/E.

What you should know: 1. Horizontal Scaling (Scaling Out/In): Adding or removing instances to distribute the load across multiple servers, improving availability and fault tolerance. Example: Using an Auto Scaling group with a load balancer to add more EC2 instances dynamically as demand increases. 2. Vertical Scaling (Scaling Up/Down): Increasing or decreasing the size (compute power, memory, etc) of a single instance, which is easier to implement for monolithic applications but has limitations (limited instance types). Example: Upgrading an instance from "t3.medium" to "m5.large". If you can understand above, then A & E are perfect choices. B - The performance issue is still there! C - Auto Scaling and Load Balancers are used for horizontal scaling, not vertical scaling. D - Horizontal scaling involves adding more instances, not changing the instance type.

BE makes more sense to me. Vertical scaling increases cost continuously even when the instance is in low demand. for a long run, the cost would be higher than just scale horizontally. The questions says the 'poor performance at specific times', so we just need to scale up at specific times. Additionally, in order to scale up, we do need AMI and a launch template. Thus, a combination of B & E should be the correct answer

You can't just scale vertically every single time you have a problem. I don't understand people who voted for A and E. You can't combine A and E. You can't stop the instance to improve memory/cpu of an instance and then add horizontal scaling to it. (spend even more). B and E

The requirements are: Resolve CPU bottlenecks (CPU hitting 100%). Improve availability. Most cost-effective.

Answer is BE

Due to monolithic application we can't scale horizontal, the scale will be vertical

The correct answers are A,E. Option A: Correct. Using AWS Compute Optimizer to obtain a recommendation for an instance type to scale vertically is an effective first step. This service analyzes your specific application workload patterns and recommends an appropriate EC2 instance type that provides better performance for the given CPU load. This approach allows you to choose a more powerful instance that can handle peak loads more effectively without immediately shifting to a horizontal scaling architecture. Option B: Incorrect by itself. Creating an AMI and a launch template is useful in setting up an Auto Scaling group or new instances but does not address the issue of CPU utilization or availability on its own. This process would be part of preparing for scaling but doesn’t directly answer the requirement of resolving performance issues by itself.

you can, you'll get for ex. 2 instances with the monolithic app, I see no issues here.

horizontal scaling is a cost-effective solution

What about options D & E? # 1 Scaling horizontally is the most cost-effective solution for handling fluctuating traffic, especially when the bottleneck is CPU utilization reaching 100% during peak times. This allows adding more instances to handle the increased load instead of upgrading to a larger instance (vertical scaling) which might be unnecessary during non-peak periods. # 2 Auto Scaling group and Application Load Balancer: These are essential components for horizontal scaling, where the Auto Scaling group automatically adjusts the number of instances based on demand, and the Application Load Balancer distributes traffic evenly across available instances. #3 AWS Compute Optimizer: This service can analyze your application usage and recommend the most cost-effective instance type for your specific needs, including suggesting options for horizontal scaling.

Read JA2018's answer below

A: Using compute optimizer helps improve performance on the monolithic web application scale up E: Enhances availability and scalibiliy

I mean the instance

it's truly difficult to answer as per the description. there are two requirement: 1. resolve performance issue => A: use compute optimizer to scale vertically, it can provides an immediate fix for high CPU utilization 2. improve availability => B + D, B is the prerequisite for D , I prefer autoscaling if must choose only one