This solution usesCloudFrontto serve the website securely over HTTPS usingAWS Certificate Manager (ACM)for SSL certificates.Origin Access Control (OAC)ensures that only CloudFront can access the S3 bucket directly.AWS WAFwith an IP set rule restricts access to the website, allowing only the on-premises IP address.Route 53is used to create an alias record pointing to the CloudFront distribution. This setup ensures secure, private access to the website with low administrative overhead.

Option A and B: S3 bucket policies and access points do not provide HTTPS support, nor do they offer the same level of security as CloudFront with WAF.

Option D: Signed URLs are more suitable for temporary, expiring access rather than a permanent solution for on-premises employees.

AWS References:

Amazon CloudFront with Origin Access Control

AWS Glue provides a serverless ETL solution requiring minimal development. Glue supports conversion to Parquet with managed jobs and integrates with S3 for output.

AWS Documentation References:

AWS Glue Overview

This solution is the most cost-effective and efficient way to break down costs per application.

Tagging Resources: By tagging all AWS resources with a specific key (e.g., " cost " ) and a value representing the application ' s name, you can easily identify and categorize costs associated with each application. This tagging strategy allows for granular tracking of costs within AWS.

Activating Cost Allocation Tags: Once tags are applied to resources, you need to activate cost allocation tags in the AWS Billing and Cost Management console. This ensures that the costs associated with each tag are included in your billing reports and can be used for cost analysis.

AWS Cost Explorer: Cost Explorer is a powerful tool that allows you to visualize, understand, and manage your AWS costs and usage over time. You can filter and group your cost data by the tags you’ve applied to resources, enabling you to easily see the cost breakdown for each application. Cost Explorer also supports generating regular reports, which can be scheduled and emailed to stakeholders.

Why Not Other Options?:

Option A (AWS Budgets): AWS Budgets is more focused on setting cost and usage thresholds and monitoring them, rather than providing detailed cost breakdowns by application.

Option B (Load Cost and Usage Reports into RDS): This approach is less cost-effective and involves more operational overhead, as it requires setting up and maintaining an RDS instance and running SQL queries.

Option D (AWS Billing and Cost Management Console): While you can download bills, this method is more manual and less dynamic compared to using Cost Explorer with activated tags.

AWS References:

AWS Tagging Strategies- Overview of how to use tagging to organize and track AWS resources.

AWS Cost Explorer- Details on how to use Cost Explorer to analyze costs.

To secure data in transit, the company should use AWS Certificate Manager (ACM) to provide SSL/TLS certificates for the Application Load Balancer. ACM allows easy provisioning, management, and renewal of public and private certificates, ensuring secure communication between users and applications.

To secure data at rest, AWS Key Management Service (KMS) is used to manage encryption keys for Amazon EBS volumes. EBS integrates with AWS KMS, allowing for server-side encryption using KMS-managed keys (SSE-KMS), thus meeting the encryption at rest requirement.

Other options:

GuardDuty (A) is for threat detection, not encryption.

AWS Shield (B) protects against DDoS attacks, not encryption.

Secrets Manager (D) manages credentials, not general data encryption.

This solution follows the AWS Well-Architected Framework – Security Pillar.

???? References:

Encrypting EBS volumes with KMS

Using ACM with ALB

Amazon Aurora MySQL provides:

Continuous, incremental backups to Amazon S3 with point-in-time recovery (PITR), allowing recovery to any point within the retention window (typically up to 35 days). This easily achieves an RPO of less than 5 hours, often down to seconds.

Support for database auditing parameters so audit logs can be retained and managed (for example, in database logs or external log services) to meet the 7-day audit requirement.

Auto scaling (via read replicas, Aurora Serverless v2, or capacity management) to handle variable read/write demand throughout the year with minimal operational overhead.

Why others are less suitable:

A: DynamoDB is NoSQL and does not directly satisfy typical relational database + SQL audit requirements; Streams also only retain 24 hours, not 7 days, and on-demand backups do not inherently give an RPO < 5 hours without frequent scheduling.

B: Amazon Redshift is a data warehouse, not a primary transactional application database.

C: Snapshots every 5 hours give an RPO of up to 5 hours, not less than 5 hours, and rely on discrete snapshot points rather than continuous PITR.

The correct answer isCbecause the workload is abatch processing jobthat runs during a limited time window each night and can tolerate interruptions. The key statement is thatif a job fails on one instance, another instance will reprocess the job. That means the workload is fault-tolerant and well suited forAmazon EC2 Spot Instances, which provide unused EC2 capacity at a much lower cost than On-Demand Instances.

Batch jobs, big data processing, background analytics, and other interruptible workloads are classic use cases for Spot Instances. Because the instances run only from12:00 AM to 06:00 AMand do not need to be available continuously, committing to a 1-year Savings Plan or Reserved Instances would not be the most cost-effective approach. Those options are better for steady and predictable long-running usage, not for short-duration nightly workloads.

Using a new launch template configured for Spot Instances allows the Auto Scaling group to launch lower-cost capacity for the processing window. Scaling based on CPU usage can help the group add or remove instances according to processing demand, improving both elasticity and cost efficiency.

Option A is less cost-effective because Savings Plans are more suitable for consistent usage over time. Option B is also less cost-effective because Reserved Instances lock in a commitment for capacity that is used only a few hours each day. Option D does not address the cost model and could even increase cost by using larger instances.

AWS cost optimization guidance recommendsSpot Instances for fault-tolerant, flexible, interruption-tolerant workloads, making optionCthe best answer.

Analysis:

The company ' s requirements are to migrate 5 PB of data from physical tapes to AWS within 6 months, preserve the data for 10 years, and ensure cost efficiency.AWS Storage Gateway Tape Gatewayis purpose-built for such use cases, as it seamlessly integrates with backup applications and provides virtual tape storage in Amazon S3 Glacier Deep Archive.

Why Option D is Correct:

Tape Gateway: Enables the migration of physical tapes to virtual tapes. Virtual tapes are stored in Amazon S3 and can later be archived in Amazon S3 Glacier Deep Archive for long-term storage.

Cost Efficiency: Amazon S3 Glacier Deep Archive is the lowest-cost storage class for long-term data preservation.

Operational Simplicity: Tape Gateway integrates with existing on-premises backup software, reducing the need for additional tools or manual processes.

Scalability: Can handle the migration of large datasets, such as 5 PB, within the required timeframe.

Why Other Options Are Not Ideal:

Option A:

AWS DataSync is not designed for reading data directly from physical tapes. Staging the data on local storage adds unnecessary complexity and cost.Not suitable.

Option B:

Using backup applications to write directly to S3 Glacier Deep Archive may not leverage AWS-native services optimally. Tape Gateway simplifies the workflow significantly.Less efficient.

Option C:

Snowball Edge is ideal for environments without high-bandwidth connectivity. However, the company already has a 10 Gbps Direct Connect, making Tape Gateway a better choice.Not cost-effective.

AWS References:

AWS Storage Gateway - Tape Gateway:AWS Documentation - Tape Gateway

Amazon S3 Glacier Deep Archive:AWS Documentation - Glacier Deep Archive

AWS documentation states that the most secure method for granting private S3 access from VPCs is to use gateway VPC endpoints for Amazon S3. Endpoint policies enforce least privilege by allowing only specific IAM roles access to specific S3 buckets. Because users can obtain temporary credentials through IAM roles, no permanent access keys must be distributed.

S3 bucket policies based on CIDR ranges (Option B) are less secure because CIDR-based access is broader and can grant unintended access. Access points (Option C) still rely on public S3 endpoints unless combined with VPC-only access, which is not stated here. Option D exposes S3 to public internet egress and depends on public IPs, violating least-privilege principles.

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AWS Step Functions is designed to coordinate multiple AWS services into serverless workflows, handling errors, retries, and complex logic. By configuring Amazon S3 Event Notifications to trigger an Amazon EventBridge rule, you can automatically start a Step Functions workflow when a new object is uploaded to S3. Step Functions can manage retries for failed uploads and orchestrate calls to various AWS services with minimal operational effort.

AWS Documentation Extract:

“You can use Amazon EventBridge to initiate AWS Step Functions workflows in response to events from S3 buckets. Step Functions can orchestrate the sequence of AWS service calls and automatically handle retries and errors, making it ideal for automating and managing complex workflows.”

(Source: AWS Step Functions documentation, Using Step Functions with EventBridge and S3)

Other options:

A: Requires manual implementation of orchestration and error handling.

B & C: Involve additional infrastructure management and custom logic for workflow orchestration and error handling, increasing operational effort.

Amazon S3 Access Grantsis designed to providefine-grained, prefix-level accessto S3 data for users and groups, including identities coming from a corporate directory or IAM Identity Center. AWS documentation explains that S3 Access Grants can map users or groups to specific S3 locations and vend temporary credentials, which makes it far more scalable than building separate IAM users, role-sharing workflows, or presigned URLs for every vendor. IAM Identity Center adds centralized user lifecycle and identity administration. This combination is especially strong when different vendors need access todifferent datasetsin the same data lake. It is also more maintainable and secure than issuing permanent IAM credentials. For auditing, the environment can still rely on AWS logging controls while using Access Grants for access distribution.

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The best security practice when providing EC2 instances access to AWS services (like S3) is to use an IAM role with an instance profile. This avoids hardcoding secrets and enables automatic credential rotation.

“We strongly recommend that you use IAM roles for applications that run on Amazon EC2 instances to securely access AWS services.”

— IAM Roles for Amazon EC2

Benefits:

No manual credentials

Temporary and automatically rotated keys

Least privilege access via IAM policies

Incorrect Options:

A: Root user access is not to be used for programmatic access.

B: Storing secret keys is insecure and discouraged.

D: MFA/versioning improves object protection, not access control.

The recommended and simplest method for granting cross-account access to an S3 bucket is to use a bucket policy that grants permission to the other AWS account.

This provides direct, controlled, IAM-based access without duplication of data or use of distribution mechanisms like CloudFront.

Transfer Acceleration and replication are unrelated to permissions.

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To access an EFS file system across accounts and VPCs, the EFS must be mounted using VPC peering or AWS Transit Gateway, and the EC2 instances must use the amazon-efs-utils package with the correct mount target or access point.

Using an EFS access point simplifies access management, especially across accounts, by providing a POSIX identity and access policy layer.

VPC sharing doesn’t support EFS directly unless the subnet and resources are shared properly, which requires redeployment. Therefore, option D is the most complete and correct.

Amazon Route 53 is a highly available and scalable authoritative DNS service. To move a public domain, you create a public hosted zone, import or recreate the zone records, and then update the registrar to use the Route 53 name servers assigned to the zone. Route 53 is globally distributed and designed for rapid propagation and resilience, and supports features such as health checks and routing policies. A private hosted zone (Option B) is resolvable only by VPCs that are associated with it and is not for public internet DNS. Directory Service and zone transfers (Option C) are unrelated to Route 53 public DNS hosting. Route 53 Resolver inbound endpoints (Option D) provide hybrid DNS forwarding for VPC workloads, not authoritative public hosting. Therefore, the fastest AWS-native migration path to a resilient managed DNS is to create a Route 53 public hosted zone and import the existing zone file.

The correct answer isBbecause the company wantshigh availability,minimum downtime,minimum data loss, and theleast operational effort. For the application tier, configuring the Auto Scaling group to spanmultiple Availability Zonesincreases resilience by ensuring that the loss of one Availability Zone does not make the application unavailable. Since the application is already behind an Application Load Balancer, traffic can continue to be routed to healthy instances in other Availability Zones.

For the database tier, the single-AZ Aurora PostgreSQL deployment represents a single point of failure. Configuring the database forMulti-AZimproves availability and durability by maintaining a synchronized standby in another Availability Zone and supporting failover with minimal disruption. This approach is aligned with AWS best practices for relational database high availability.

UsingAmazon RDS Proxyfurther improves availability at the application layer by managing database connections efficiently and helping applications reconnect more quickly during failover events. This reduces the operational complexity of handling transient database interruptions and can improve application resilience.

Option A introduces multi-Region complexity, which is not required to meet the stated need and creates more operational overhead. Option C does not provide high availability because snapshots are a backup and restore mechanism, not an automatic failover solution, and hourly snapshots can result in significant data loss. Option D is unnecessarily complex and changes the application data flow in a way that is not needed.

The simplest and most AWS-aligned solution is to make both the compute and database layers highly available acrossmultiple Availability Zones. That provides resilience with the least operational burden.

Amazon EFS provides a shared, fully managed, POSIX-compliant file system that can be mounted by all EC2 instances. Any update made to the file system is immediately visible to all instances, ensuring every new instance has the latest product manuals without delay.

EFS automatically scales storage and throughput, meeting high-demand conditions with no application changes required.

S3 requires instances to download files locally, causing delay and stale data issues (Options B and D). Instance store volumes (Option A) are ephemeral and not shared, making them unsuitable for consistent data distribution.

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The best practice to securely provide short-term access to AWS resources, such as Amazon S3, without using long-term credentials, is to use AWS Security Token Service (STS). According to the AWS IAM Best Practices and the Security Pillar of the AWS Well-Architected Framework, temporary credentials should always be used over long-term credentials when possible.

From AWS IAM Documentation:

“Use temporary credentials (IAM roles and AWS STS) instead of long-term access keys. Temporary security credentials are short-term, automatically expire, and are retrieved using AWS STS.”

(Source: IAM Best Practices – IAM User Guide)

Option D outlines the use of a trust relationship and assume-role mechanism via AWS STS. This allows the on-premises application to request temporary, scoped-down credentials to upload files to S3 securely. This approach is:

Secure – Uses short-lived credentials with least privilege

Scalable – No need for EC2 or VPN tunnels

Low Operational Overhead – No infrastructure to maintain

AWS-Recommended – Aligned with security best practices

In contrast:

Option A uses long-term credentials, which is a security risk.

Option B requires additional infrastructure (EC2, VPN), increasing complexity and cost.

Option C relies on IP-based access, which is insecure and not a form of identity-based authentication.

AWS Elastic Disaster Recovery (AWS DRS) enables fast, reliable, and cost-effective disaster recovery. It replicates on-premises machines to AWS using continuous block-level replication. It supports automated testing and failover, meeting aggressive RTO targets such as 15 minutes.

AWS Storage Gateway stored volume gateway is designed for use cases where:

The primary data set remains on premises.

You want to maintain full local access to data with low latency.

You need asynchronous, secure replication and backup to AWS.

With stored volumes, you:

Map gateway storage volumes to local on-premises disks.

Present these volumes as iSCSI block devices to on-prem systems.

Storage Gateway then asynchronously backs up snapshots to Amazon S3, providing secure, durable offsite backup automatically.

Cached volume gateway (Option C) keeps the primary copy in AWS and only a subset cached locally, which does not meet the requirement to maintain full local access to all data.

Snowball and Snowball Edge (Options A and B) are primarily for bulk, one-time or periodic offline data transfer and do not provide an ongoing backup solution with continuous local access.

Amazon S3 Glacier Flexible Retrieval is designed for long-lived, infrequently accessed data where retrieval times of minutes to hours are acceptable. It offers very low storage cost per GB while still supporting faster retrieval than archival tiers that can take many hours or days.

The requirement states that data is rarely accessed and must be retrievable within 12 hours. Glacier Flexible Retrieval meets this retrieval-time requirement and is more cost-effective per GB than Standard and Infrequent Access storage classes for long-term, rarely accessed data.

S3 Standard, S3 Standard-IA, and S3 One Zone-IA are optimized for more frequent or lower-latency access and have higher storage cost per GB compared to Glacier Flexible Retrieval.