Amazon Web Services Updated CLF-C02 Exam Questions and Answers by azalea

Decoupling the components of an application means reducing the dependencies and interactions between them, which can improve the application’s reliability, scalability, and performance. Decoupling can be achieved by using services such as Amazon Simple Queue Service (Amazon SQS), Amazon Simple Notification Service (Amazon SNS), and AWS Lambda1

Amazon EC2 Spot Instances let you take advantage of unused EC2 capacity in the AWS cloud. Spot Instances are available at up to a 90% discount compared to On-Demand prices. You can use Spot Instances for various stateless, fault-tolerant, or flexible applications such as big data, containerized workloads, CI/CD, web servers, high-performance computing (HPC), and other test & development workloads. Spot Instances are well-suited for massively parallel computations, as they can provide large amounts of compute capacity at a low cost, and can be interrupted with a two-minute notice3

Cost optimization is the pillar of the AWS Well-Architected Framework that aligns with the requirements of not relying on elaborate forecasting and paying only for the resources that are used. The cost optimization pillar focuses on the ability of a system to deliver business value at the lowest price point. Cost optimization involves using the right AWS services and resources for the workload, measuring and monitoring the cost and usage, and continuously improving the cost efficiency. Cost optimization also leverages the benefits of the AWS Cloud, such as pay-as-you-go pricing, elasticity, and scalability. For more information, see [Cost Optimization Pillar] and [Cost Optimization].

Scaling horizontally across multiple Availability Zones is a way to adopt a highly available architecture, as it increases the fault tolerance and resilience of the application. Scaling vertically to a larger EC2 instance size is a way to improve the performance of the application, but it does not improve the availability. Purchasing an EC2 Dedicated Instance is a way to isolate the instance from other AWS customers, but it does not improve the availability. Changing the EC2 instance family to a compute optimized instance is a way to optimize the instance type for the workload, but it does not improve the availability. These concepts are explained in the AWS Well-Architected Framework2.