Explanation: AWS CloudFormation is a service that allows you to model and provision your AWS and third-party application resources in a repeatable and predictable way. You can use AWS CloudFormation to create, update, and delete a collection of resources as a single unit, called a stack. You can also use AWS CloudFormation to manage your development and production environments in a consistent and efficient manner4.

Explanation: A is correct because Amazon RDS is the AWS service that provides a managed relational database service that supports various database engines, such as MySQL, PostgreSQL, Oracle, and SQL Server. B is incorrect because Amazon Redshift is the AWS service that provides a managed data warehouse service that is optimized for analytical queries. C is incorrect because Amazon ElastiCache is the AWS service that provides a managed in-memory data store service that supports Redis and Memcached. D is incorrect because Amazon Neptune is the AWS service that provides a managed graph database service that supports property graph and RDF models.

Explanation: Cost Explorer is an AWS service or tool that can be used to forecast AWS spending. It allows users to analyze their AWS costs and usage using interactive graphs and tables. It also provides features such as filtering, grouping, and forecasting to help users plan their future spending. Amazon DevPay is an AWS service that allows developers to sell applications that are built on AWS services. It handles the billing and metering for the customers of the applications and collects payments from them. It is not a tool for forecasting AWS spending. AWS Organizations is an AWS service that allows users to centrally manage and govern their AWS accounts. It provides features such as creating groups of accounts, applying policies, and automating account creation. It is not a tool for forecasting AWS spending. AWS Trusted Advisor is an AWS service that provides best practices and recommendations to optimize the performance, security, and cost of AWS resources. It can help users identify opportunities to reduce their AWS costs, but it is not a tool for forecasting AWS spending

Explanation: AWS Service Catalog is a service that allows you to create and manage catalogs of IT services that are approved for use on AWS. You can use AWS Service Catalog to centrally manage commonly deployed IT services and help your organization achieve consistent governance and meet your compliance requirements, while enabling users to quickly deploy only the approved IT services they need1. AWS Config is a service that enables you to assess, audit, and evaluate the configurations of your AWS resources. AWS software development kits (SDKs) are tools that enable you to easily integrate your applications with AWS services using your preferred programming language. AWS AppSync is a service that simplifies application development by letting you create a flexible API to securely access, manipulate, and combine data from one or more data sources. None of these services can help you limit your employees’ AWS access to a portfolio of predefined AWS resources.

Explanation: AWS Secrets Manager is a service that helps you protect access to your applications, services, and IT resources. This service enables you to easily rotate, manage, and retrieve database credentials, API keys, and other secrets throughout their lifecycle1. Amazon S3 is a storage service that does not offer automatic rotation of credentials. AWS Systems Manager Parameter Store is a service that provides secure, hierarchical storage for configuration data management and secrets management2, but it does not offer automatic rotation of credentials. AWS CloudTrail is a service that enables governance, compliance, operational auditing, and risk auditing of your AWS account3, but it does not store or rotate credentials.

Explanation: AWS Config is a service that enables you to assess, audit, and evaluate the configurations of your AWS resources. AWS Config continuously monitors and records your AWS resource configurations and allows you to automate the evaluation of recorded configurations against desired configurations. With AWS Config, you can review changes in configurations and relationships between AWS resources, dive into detailed resource configuration histories, and determine your overall compliance against the configurations specified in your internal guidelines. This can help you simplify compliance auditing, security analysis, change management, and operational troubleshooting1.

Explanation: AWS Shield Standard and AWS WAF are the AWS services or tools that are designed to protect a workload from SQL injections, cross-site scripting, and DDoS attacks. According to the AWS Shield Developer Guide, "AWS Shield is a managed Distributed Denial of Service (DDoS) protection service that safeguards applications running on AWS. AWS Shield provides always-on detection and automatic inline mitigations that minimize application downtime and latency, so there is no need to engage AWS Support to benefit from DDoS protection."5 According to the AWS WAF Developer Guide, “AWS WAF is a web application firewall that helps protect your web applications or APIs against common web exploits that may affect availability, compromise security, or consume excessive resources. AWS WAF gives you control over how traffic reaches your applications by enabling you to create security rules that block common attack patterns, such as SQL injection or cross-site scripting, and rules that filter out specific traffic patterns you define.” VPC endpoint, virtual private gateway, and AWS Config are not designed to protect a workload from these types of attacks.

Explanation: AWS Pricing Calculator is the AWS service or tool that the company should use to estimate its future AWS service costs before the migration. AWS Pricing Calculator is a web-based tool that allows the company to create cost estimates for various AWS services and scenarios. AWS Pricing Calculator helps the company to compare the costs of running the workload on premises versus on AWS, and to optimize the costs by choosing the best options for the workload. AWS Pricing Calculator also provides a detailed breakdown of the cost components and a downloadable report.

Explanation: AWS Cloud Adoption Framework (AWS CAF) is a service or tool that helps users migrate their applications to the AWS Cloud. It provides guidance and best practices to identify and prioritize any business transformation opportunities and evaluate their AWS Cloud readiness. It also helps users align their business and technical perspectives, create an actionable roadmap, and measure their progress. AWS Managed Services (AMS) is a service that provides operational services for AWS infrastructure and applications. It helps users reduce their operational overhead and risk, and focus on their core business. It does not help users identify and prioritize any business transformation opportunities and evaluate their AWS Cloud readiness. AWS Well-Architected Framework is a tool that helps users design and implement secure, high-performing, resilient, and efficient solutions on AWS. It provides a set of questions and best practices across five pillars: operational excellence, security, reliability, performance efficiency, and cost optimization. It does not help users identify and prioritize any business transformation opportunities and evaluate their AWS Cloud readiness. AWS Migration Hub is a service that provides a single location to track and manage the migration of applications to AWS. It helps users discover their onpremises servers, group them into applications, and choose the right migration tools. It does not help users identify and prioritize any business transformation opportunities and evaluate their AWS Cloud readiness.

Explanation: D is correct because security groups are the AWS service or feature that can be used to control inbound and outbound traffic on an Amazon EC2 instance. Security groups act as a virtual firewall for the EC2 instance, allowing users to specify which protocols, ports, and source or destination IP addresses are allowed or denied. A is incorrect because internet gateways are the AWS service or feature that enable communication between instances in a VPC and the internet. They do not control the traffic on an EC2 instance. B is incorrect because AWS Identity and Access Management (IAM) is the AWS service or feature that enables users to manage access to AWS services and resources securely. It does not control the traffic on an EC2 instance. C is incorrect because network ACLs are the AWS service or feature that provide an optional layer of security for the VPC that acts as a firewall for controlling traffic in and out of one or more subnets. They do not control the traffic on an EC2 instance.

Explanation: Using EC2 instances across multiple Availability Zones in the same AWS Region is a solution that meets the requirements of sharing the same geographic area but using redundant underlying power sources. Availability Zones are isolated locations within an AWS Region that have independent power, cooling, and physical security. They are connected through low-latency, high-throughput, and highly redundant networking. By launching EC2 instances in different Availability Zones, users can increase the fault tolerance and availability of their applications. Amazon CloudFront is a content delivery network (CDN) service that speeds up the delivery of web content and media to end users by caching it at the edge locations closer to them. It is not a database service and cannot be used to store operational data for EC2 instances. Edge locations are sites that are part of the Amazon CloudFront network and are located in many cities around the world. They are not the same as Availability Zones and do not provide redundancy for EC2 instances. AWS OpsWorks is a configuration management service that allows users to automate the deployment and management of applications using Chef or Puppet. It can be used to create stacks that span multiple AWS Regions, but this would not meet the requirement of sharing the same geographic area.

Explanation: Amazon CloudWatch and AWS CloudTrail are the AWS services that allow users to monitor and retain records of account activities that include governance, compliance, and auditing. Amazon CloudWatch is a service that collects and tracks metrics, collects and monitors log files, and sets alarms. AWS CloudTrail is a service that enables governance, compliance, operational auditing, and risk auditing of your AWS account. Amazon GuardDuty, AWS Shield, and AWS WAF are AWS services that provide security and protection for AWS resources, but they do not monitor and retain records of account activities. These concepts are explained in the AWS Cloud Practitioner Essentials course3.