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

 B is correct because Reserved Instances are the instance purchasing option that offers the most cost-effective way to use Amazon EC2 instances for a stable production workload that will run for 1 year, as they provide significant discounts compared to On-Demand Instances in exchange for a commitment to use a specific amount of computing power for a period of time. A is incorrect because Dedicated Hosts are the instance purchasing option that allows customers to use physical servers that are fully dedicated to their use, which is more expensive and less flexible than Reserved Instances. C is incorrect because On-Demand Instances are the instance purchasing option that allows customers to pay for compute capacity by the hour or second with no long-term commitments, which is more suitable for short-term, variable, and unpredictable workloads. D is incorrect because Spot Instances are the instance purchasing option that allows customers to bid on spare Amazon EC2 computing capacity, which is more suitable for flexible, scalable, and fault-tolerant workloads that can tolerate interruptions.

 Spot Instances are instances that use spare EC2 capacity that is available for up to 90% off the On-Demand price. Because Spot Instances can be interrupted by EC2 with two minutes of notification when EC2 needs the capacity back, you can use them for applications that have flexible start and end times, or that can withstand interruptions5. This option is most cost-effective for the use case described in the question. Reserved Instances are instances that you purchase for a one-year or three-year term, and pay a lower hourly rate compared to On-Demand Instances. This option is suitable for applications that have steady state or predictable usage. Dedicated Instances are instances that run on hardware that’s dedicated to a single customer within an Amazon VPC. This option is suitable for applications that have stringent regulatory or compliance requirements. On-Demand Instances are instances that you pay for by the second, with no long-term commitments or upfront payments. This option is suitable for applications that have unpredictable or intermittent workloads.

The AWS service that is used to temporarily provide federated security credentials to a user is AWS Security Token Service (AWS STS). AWS STS is a service that enables customers to request temporary, limited-privilege credentials for AWS Identity and Access Management (IAM) users or for users that they authenticate (federated users). The company can use AWS STS to grant federated users access to AWS resources without creating permanent IAM users or sharing long-term credentials. AWS STS helps customers manage and secure access to their AWS resources for federated users. Amazon GuardDuty, AWS Secrets Manager, and AWS Certificate Manager are not the best services to use for this purpose. Amazon GuardDuty is a threat detection service that monitors for malicious activity and unauthorized behavior across the AWS accounts and resources. AWS Secrets Manager is a service that helps customers manage and rotate secrets, such as database credentials, API keys, and passwords. AWS Certificate Manager is a service that helps customers provision, manage, and deploy public and private Secure Sockets Layer/Transport Layer Security (SSL/TLS) certificates for use with AWS services and internal connected resources. These services are more useful for different types of security and compliance tasks, rather than providing temporary federated security credentials to a user.

 According to the AWS shared responsibility model, the customer is responsible for configuring logical access controls for resources, and protecting account credentials. This includes managing IAM user permissions, security group rules, network ACLs, encryption keys, and other aspects of access management1. AWS is responsible for protecting the global infrastructure that runs all of the services offered in the AWS Cloud, such as the hardware, software, networking, and facilities. AWS is also responsible for configuring the security used by managed services, such as Amazon RDS, Amazon DynamoDB, and Amazon Aurora2.