AWS CloudHSM provides hardware-based key management to manage and protect encryption keys in the AWS Cloud. It allows customers to generate and use their own encryption keys while complying withrigorous security requirements. WhileAWS Certificate Manager (ACM)manages SSL/TLS certificates, it does not handle encryption keys independently, andAWS License ManagerandAWS Directory Serviceare not designed for managing encryption keys. AWS KMS is also relevant for key management but wasn't listed as an option in this question.

Amazon S3 Glacier Flexible Retrieval is optimized for storing infrequently accessed data at a very low cost, making it suitable for data archiving and long-term backups. It provides flexible retrieval options for archived data. Other services like FSx for Lustre, EBS, and EFS are more suited for frequently accessed data and higher-performance use cases, not archival storage.

Security groups and network ACLs are two AWS services that can be used to block network traffic to an instance. Security groups are virtual firewalls that control the inbound and outbound traffic for your instances at the instance level. You can specify which protocols, ports, and source or destination IP addresses are allowed or denied for each instance. Security groups are stateful, which means that they automatically allow return traffic for any allowed inbound or outbound traffic123. Network ACLs are virtual firewalls that control the inbound and outbound traffic for your subnets at the subnet level. You can create rules to allow or deny traffic based on protocols, ports, and source or destination IP addresses. Network ACLs are stateless, which means that you have to explicitly allow return traffic for any allowed inbound or outbound traffic456. References: 1: Security groups for your VPC - Amazon Virtual Private Cloud, 2: Security Groups for Your VPC - Amazon Elastic Compute Cloud, 3: AWS Security Groups: Everything You Need to Know, 4: Network ACLs - Amazon Virtual Private Cloud, 5: Control traffic to subnetsusing network ACLs - Amazon Virtual Private Cloud, 6: AWS Network ACLs: Everything You Need to Know

One of the key advantages of cloud computing is the ability totrade fixed expenses (like data centers and physical servers) for variable expenses. With AWS, companies pay only for the compute power, storage, and other resources they use, rather than investing heavily in on-premises infrastructure upfront. This reduces capital expenditure and helps lower overall costs.

Why other options are not suitable:

A. Go global in minutes: Refers to the ability to quickly deploy applications around the world, but does not directly reduce upfront costs.

B. Increase speed and agility: Refers to the ability to quickly scale and deploy resources, but is not directly related to cost reduction.

C. Benefit from massive economies of scale: Refers to AWS's ability to lower costs by leveraging its scale, but the primary advantage for reducing upfront costs is moving from fixed to variable expenses.

The company is following the best practice of implementing loosely coupled dependencies by migrating the application to AWS and dividing the application into microservices. Loosely coupled dependencies are a design principle of the AWS Well-Architected Framework that helps to reduce the interdependencies between components and improve the scalability, reliability, and performance of the system. By breaking down the monolithic application into smaller, independent, and modular services, the company can reduce the complexity and maintenance costs, increase the agility and flexibility, and enable faster and more frequent deployments. AWS CloudFormation is an AWS service that provides the ability to manage infrastructure as code. Infrastructure as code is a process of defining and provisioning AWS resources using code or templates, rather than manual actions or scripts. AWS CloudFormation allows users to create and update stacks of AWS resources based on predefined templates that describe the desired state and configuration of the resources. AWS CloudFormation automates and simplifies the deployment and management of AWS resources, and ensures consistency and repeatability across different environments and regions. AWS CloudFormation also supports rollback, change sets, drift detection, and nested stacks features that help users to monitor andcontrol the changes to their infrastructure. References: Implementing Loosely Coupled Dependencies, What is AWS CloudFormation?

Amazon CloudFront is a content delivery network (CDN) that uses edge locations to cache content closer to users, reducing latency and improving performance. It supports the delivery of web content, such as videos and images, by caching copies at edge locations around the world. Amazon Kinesis, SQS, and Route 53 do not utilize edge locations for content caching.

On-Demand Instances are the most cost-efficient pricing model for an uninterruptible workload that runs once a year for 24 hours. On-Demand Instances let you pay for compute capacity by the hour or second, depending on which instances you run. No long-term commitments or up-front payments are required. You can increase or decrease your compute capacity to meet the demands of your application and only pay the specified hourly rates for the instance you use1. This model is suitable for developing/testing applications with short-term or unpredictable workloads2. The other pricing models are not cost-efficient for this use case. Reserved Instances and Savings Plans require a commitment to a consistent amount of usage, in USD per hour, for a term of 1 or 3 years. They provide significant discounts compared to On-Demand Instances, but they are not flexible or scalable for workloads that run only once a year12. Spot Instances are the cheapest option, but they are not suitable for uninterruptible workloads, as they can be reclaimed by AWS at any time. They are recommended for applications that have flexible start and end times, or that are only feasible at very low compute prices12. Dedicated Instances are designed for compliance and licensing requirements, not for cost optimization. They are more expensive than the other options, as they run on single-tenant hardware12. References: Amazon EC2 – Secure and resizable compute capacity – AWS, Amazon EC2 - How AWS Pricing Works

Amazon Elastic File System (Amazon EFS) is a fully managed, scalable, and serverless NFS (Network File System) file system specifically designed for use with AWS services and on-premises resources. It enables companies to create and configure file systems that can be accessed from multiple Amazon EC2instances simultaneously, making it ideal for use cases that require shared file storage for AWS compute services.

Why Amazon EFS Fits the Requirements:

Managed Service: Amazon EFS is a fully managed file storage service that simplifies the process of setting up and managing NFS file systems.

Scalability and Elasticity: EFS automatically scales to accommodate the storage needs of applications, without the need to provision or manage storage capacity.

NFS Compatibility: Amazon EFS natively supports the NFSv4 protocol, making it compatible with a wide range of applications and workloads that require NFS access.

Integration with AWS Compute Services: EFS integrates seamlessly with Amazon EC2 and other AWS services, providing a shared file storage solution across multiple instances and services within the AWS cloud environment.

Why Other Options Do Not Fit:

A. Amazon Elastic Block Store (Amazon EBS): While EBS provides block-level storage that can be attached to individual EC2 instances, it is not a file system, nor does it provide managed NFS file storage capabilities. EBS is designed for single-instance access rather than shared file access across multiple instances.

B. AWS Storage Gateway Tape Gateway: Tape Gateway is designed for archival purposes and allows companies to store virtual tape backups in Amazon S3 or Glacier. It does not support NFS file storage and is not intended for regular compute access.

C. Amazon S3 Glacier Flexible Retrieval: Amazon S3 Glacier is optimized for data archiving and long-term storage of infrequently accessed data, but it does not provide NFS file system capabilities, nor is it suitable for high-performance access needs associated with compute services.

For more details, you can refer to theAWS Cloud Practitioner Essentialscontent, specifically the modules onStorage Serviceswhere Amazon EFS is covered as the managed NFS file storage solution offered by AWS.

AWS Trusted Advisor is an online tool that provides you real time guidance to help you provision your resources following AWS best practices, including security and performance. It can help you monitor for misconfigured security groups that are allowing unrestricted access to specific ports. Amazon CloudWatch is a service that monitors your AWS resources and the applications you run on AWS. Amazon GuardDuty is a threat detection service that continuously monitors for maliciousactivity and unauthorized behavior. AWS Health Dashboard provides relevant and timely information to help you manage events in progress, and provides proactive notification to help you plan for scheduled activities.

AWS Shared Responsibility Model Overview:

AWS manages securityofthe cloud, including physical infrastructure and foundational services.

Customers are responsible for securityinthe cloud, which includes operating system configuration, data encryption, and application patch management.

Why Patch Management Is Shared:

AWS is responsible for patching the underlying infrastructure.

Customers are responsible for patching the operating system and applications they install on their resources (e.g., EC2 instances).

Why Other Options Are Incorrect:

A. Configuration of Amazon EC2 instance operating systems:Fully the customer’s responsibility.

B. Application file system server-side encryption:Customers configure and manage encryption.

D. Security of the physical infrastructure:Fully AWS’s responsibility.

AWS Secrets Manager is a service designed to securely store and manage access to sensitive information such as API keys, passwords, and database credentials. It allows automatic rotation, secure storage, and fine-grained access control for these credentials, ensuring they are securely managed. The other options do not provide encrypted storage for credentials specifically.