Free Amazon Web Services SAA-C03 Practice Exam with Questions & Answers | Set: 7

AWS Storage Gateway Volume Gateway provides two configurations for connecting to iSCSI storage, namely, stored volumes and cached volumes. The stored volume configuration stores the entire data set on-premises and asynchronously backs up the data to AWS. The cached volume configuration stores recently accessed data on-premises, and the remaining data is stored in Amazon S3. Since the company wants only its recently accessed data to remain stored locally, the cached volume configuration would be the most appropriate. It allows the company to keep frequently accessed data on-premises and reduce the need for scaling its iSCSI storage while still providing access to all data through the AWS cloud. This configuration also provides low-latency access to frequently accessed data and cost-effective off-site backups for less frequently accessed data.

https://docs.amazonaws.cn/en_us/storagegateway/latest/vgw/StorageGatewayConcepts.html#storage-gateway-cached-concepts

This solution satisfies the requirements in the following ways:

• AWS Backup will automatically take full backups of the DynamoDB table on the schedule defined in the backup plan (the first of each month).

• The lifecycle policy can transition backups to cold storage after 6 months, meeting that requirement.

• Setting a 7-year retention period in the backup plan will ensure each backup is retained for 7 years as required.

• AWS Backup manages the backup jobs and lifecycle policies, requiring no custom scripting or management.

This option will scale up capacity faster in the morning to improve performance, but will still allow capacity to scale down during off hours. It achieves this as follows: • A target tracking action scales based on a CPU utilization target. By triggering at a lower CPU threshold in the morning, the Auto Scaling group will start scaling up sooner as traffic ramps up, launching instances before utilization gets too high and impacts performance. • Decreasing the cooldown period allows Auto Scaling to scale more aggressively, launching more instances faster until the target is reached. This speeds up the ramp-up of capacity. • However, unlike a scheduled action to set a fixed minimum/maximum capacity, with target tracking the group can still scale down during off hours based on demand. This helps minimize costs.

https://aws.amazon.com/blogs/networking-and-content-delivery/adding-http-security-headers-using-lambdaedge-and-amazon-cloudfront/

Amazon CloudFront is a global content delivery network (CDN) service that can securely deliver web content, videos, and APIs at scale. It integrates with Cognito for authentication and with Lambda@Edge for authorization, making it an ideal choice for serving web content globally. Lambda@Edge is a service that lets you run AWS Lambda functions globally closer to users, providing lower latency and faster response times. It can also handle authorization logic at the edge to secure content in CloudFront. For this scenario, Lambda@Edge can provide authorization for the web application while leveraging the low-latency benefit of running at the edge.

https://medium.com/awesome-cloud/aws-difference-between-multi-az-and-read-replicas-in-amazon-rds-60fe848ef53a

The data retention period of a Kinesis data stream is the time period from when a record is added to when it is no longer accessible1. Thedefault retention period for a Kinesis data stream is 24 hours, which can be extended up to 8760 hours (365 days)1. The dataretention period can be updated by using the AWS Management Console, the AWS CLI, or the Kinesis Data Streams API1.

To meet the requirements of the scenario, the solutions architect should update the Kinesis Data Streams default settings by modifying the data retention period. The solutions architect should increase the retention period to a value that is greater than or equal to thefrequency of consuming the data and writing itto S32. This way, the company can ensure that S3 receives all the data that the application sends to Kinesis Data Streams.

Frequent feature testing -

- Multiple Elastic Beanstalk environments can be created easily for development, testing and production use cases.

- Traffic can be routed between environments for A/B testing and feature iteration using simple URL swapping techniques. No complex routing rules or infrastructure changes required.

Amazon SES is a cost-effective and scalable email service that enables businesses to send and receive email using their own email addresses and domains. Configuring the web instance to send email through Amazon SES is a simple and effective solution that can reduce the time spent resolving complex email delivery issues and minimize operational overhead.

Amazon Cognito identity pools assign your authenticated users a set of temporary, limited-privilege credentials to access your AWS resources. The permissions for each user are controlled through IAM roles that you create.https://docs.aws.amazon.com/cognito/latest/developerguide/role-based-access-control.html

RDS supported Storage > https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Storage.html GP2 max IOPS >https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/general-purpose.html#gp2-performance

Amazon RDS provides three storage types: General Purpose SSD (also known as gp2 and gp3), Provisioned IOPS SSD (also known as io1), and magnetic (also known as standard).They differ in performance characteristics and price, which means that you can tailor your storage performance and cost to the needs of your database workload. You can create MySQL,MariaDB, Oracle, and PostgreSQL RDS DB instances with up to 64 tebibytes (TiB) of storage. You can create SQL Server RDS DB instances with up to 16 TiB of storage. For this amount of storage, use the Provisioned IOPS SSD and General Purpose SSD storage types.https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Storage.html

it allows the company to migrate its data from the on-premises location to an Amazon S3 bucket and automatically validate the integrity of the data after the transfer. By deploying an AWS DataSync agent on premises, the company can use a fully managed data transfer service that makes it easy to move large amounts of data to and from AWS. By configuring the DataSync agent to perform the online data transfer to an S3 bucket, the company can take advantage of DataSync’s features, such as encryption, compression, bandwidth throttling, and data validation. DataSync automatically verifies data integrity at both source and destination after each transfer task. References:

AWS DataSync

Deploying an Agent for AWS DataSync

How AWS DataSync Works

Enabling Amazon Elastic Block Store (Amazon EBS) fast snapshot restore on a snapshot allows you to quickly create a new Amazon Machine Image (AMI) from a snapshot, which can help reduce the initialization latency when provisioning new instances. Once the AMI is provisioned, you can replace the AMI in the Auto Scaling group with the new AMI. This will ensure that new instances are launched from the updated AMI and are able to meet the increased demand quickly.

https://aws.amazon.com/blogs/database/dynamodb-streams-use-cases-and-design-patterns/

https://aws.amazon.com/premiumsupport/knowledge-center/back-up-dynamodb-s3/

To store and view engineering drawings with caching support, Amazon S3 and Amazon CloudFront are suitable solutions. Amazon S3 can store any amount of data with high durability, availability, and performance. Amazon CloudFront can distribute the engineering drawings to edge locations closer to the users, which can reduce the latency and improve the user experience. Amazon CloudFront can also cache the engineering drawings at the edge locations, which can minimize the amount of time that users wait for the drawings to load.

Amazon API Gateway is a fully managed service that makes it easy for developers to create, publish, maintain, monitor, and secure APIs at any scale. AWS Lambda is a serverless compute service that lets you run code without provisioning or managing servers. Lambda scales automatically based on the incoming requests, but it may take some time to initialize new instances of your function if there is a sudden increase in demand. This may result in high latency or cold starts for your API. To avoid this, you can use provisioned concurrency, which ensures that your function is initialized and ready to respond at any time. Provisioned concurrency also helps you achieve consistent low latency for your API by reducing the impact of scaling on performance. References:https://docs.aws.amazon.com/apigateway/latest/developerguide/http-api-develop-integrations-lambda.htmlhttps://docs.aws.amazon.com/lambda/latest/dg/configuration-concurrency.html

This answer is correct because it meets the requirements of maximizing the reliability of the application’s infrastructure. You can update the DB instance to be Multi-AZ, which means that Amazon RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone. The primary DB instance is synchronously replicated across Availability Zones to a standby replica to provide data redundancy and minimize latency spikes during system backups. Running a DB instance with high availability can enhance availability during planned system maintenance. It can also help protect your databases against DB instance failure and Availability Zone disruption. You can also enable deletion protection on the DB instance, which prevents the DB instance from being deleted by any user. You can place the EC2 instances behind an Application Load Balancer, which distributes incoming application traffic across multiple targets, such as EC2 instances, in multiple Availability Zones. This increases the availability and fault tolerance of your applications. You can run the EC2 instances in an EC2 Auto Scaling group across multiple Availability Zones, which ensures that you have the correct number of EC2 instances available to handle the load for your application. You can use scaling policies to adjust the number of instances in your Auto Scaling group in response to changing demand.

This solution provides the most secure access for external support engineers with the least exposure to potential security risks.

AWS Systems Manager (SSM) and Session Manager: Systems Manager Session Manager allows secure and auditable access to EC2 instances without the need to open inbound SSH ports or manage SSH keys. This reduces the attack surface significantly. The SSM Agent must be installed and configured on all instances, and the instances must have an instance profile with the necessary IAM permissions to connect to Systems Manager.

IAM Identity Center: IAM Identity Center provides centralized management of access to the AWS Management Console for external support engineers. By using IAM Identity Center, youcan control console access securely and ensure that external engineers have the appropriate permissions based on their roles.

Why Not Other Options?:

Option B (Local IAM user credentials): This approach is less secure because it involves managing local IAM user credentials and does not leverage the centralized management and security benefits of IAM Identity Center.

Option C (Security group with SSH access): Allowing SSH access opens up the infrastructure to potential security risks, even when restricted by IP addresses. It also requires managing SSH keys, which can be cumbersome and less secure.

Option D (Bastion host): While a bastion host can secure SSH access, it still requires managing SSH keys and opening ports. This approach is less secure and more operationally intensive compared to using Session Manager.

AWS References:

AWS Systems Manager Session Manager- Documentation on using Session Manager for secure instance access.

AWS IAM Identity Center- Overview of IAM Identity Center and its capabilities for managing user access.

AWSCost Anomaly Detection allows you to create monitors that track the cost and usage of your AWS resources and alert you when there is an unusual spending pattern. You can create monitors based on different dimensions, such as AWS services, accounts, tags, or cost categories. You can also create alert subscriptions that notify you by email or Amazon SNS when an anomaly is detected. You can specify the threshold and frequency of the alerts, and choose to receive weekly summaries of your anomalies.

Reference URLs:

1 https://aws.amazon.com/aws-cost-management/aws-cost-anomaly-detection/

2 https://docs.aws.amazon.com/cost-management/latest/userguide/getting-started-ad.html

3 https://docs.aws.amazon.com/cost-management/latest/userguide/manage-ad.html

A NAT gateway enables EC2 instances in private subnets to initiate outbound IPv4 internet requests while blocking inbound traffic from the internet. Deploying NAT gateways in public subnets across two Availability Zones ensures high availability and meets the requirement for outbound-only internet access.

Option B:An internet gateway allows inbound and outbound traffic, violating the requirement to block public IPv4 access.

Option C:A shared route table does not provide the desired separation of routing for highly available architecture.

Option D:Egress-only internet gateways are designed for IPv6 traffic, not IPv4.

AWS Documentation References:

NAT Gateway Overview

Private Subnet Route Tables

A gateway VPC endpoint for Amazon S3 enables private connections between the VPC and Amazon S3 that do not require an internet gateway or NAT device. This minimizes costs and prevents traffic from traversing the internet. A gateway VPC endpoint uses a prefix list as the routetarget in a VPC route table to route traffic privately to Amazon S31.Associating the endpoint with all route tables in the VPC ensures that all subnets can access Amazon S3 through the endpoint.

Option A is incorrect because S3 Intelligent-Tiering is a storage class that optimizes storage costs by automatically moving objects between two access tiers based on changing access patterns. It does not affect the network traffic between the VPC and Amazon S32.

Option B is incorrect because S3 Transfer Acceleration is a feature that enables fast, easy, and secure transfers of files over long distances between clients and an S3 bucket. It does not prevent traffic from traversing the internet3.

Option D is incorrect because an interface VPC endpoint for Amazon S3 is powered by AWS PrivateLink, which requires an elastic network interface (ENI) with a private IP address in each subnet. This adds complexity and cost to the solution. Moreover, an interface VPC endpoint does not support cross-Region access to Amazon S3. Reference URL: 1: https://docs.aws.amazon.com/vpc/latest/privatelink/vpc-endpoints-s3.html 2: https://docs.aws.amazon.com/AmazonS3/latest/userguide/storage-class-intro.html#sc-dynamic-data-access 3: https://docs.aws.amazon.com/AmazonS3/latest/userguide/transfer-acceleration.html : https://aws.amazon.com/blogs/architecture/choosing-your-vpc-endpoint-strategy-for-amazon-s3/

AWS Global Accelerator directs traffic to the optimal healthy endpoint based on health checks, it can also route traffic to the closest healthy endpoint based on geographic locationof the client. By configuring an accelerator and attaching it to a Regional endpoint in each Region, and adding the ALB as the endpoint, the solution will redirect traffic to healthy endpoints, improving the user experience by reducing latency and ensuring that the application is running optimally. This solution will ensure that traffic is directed to the closest healthy endpoint and will help to improve the overall user experience.

AWS uses the existing infrastructure of a VPC to create a VPC peering connection; it is neither a gateway nor a VPN connection, and does not rely on a separate piece of physical hardware. There is no single point of failure for communication or a bandwidth bottleneck.https://docs.aws.amazon.com/vpc/latest/peering/what-is-vpc-peering.html

AWS Organizations is a service that helps users centrally manage and govern multiple AWS accounts. It allows users to create organizational units (OUs) to group accounts based on business needs or other criteria. It also allows users to define and attach service control policies (SCPs) to OUs or accounts to restrict the actions that can be performed by the accounts1. By using AWS Organizations, the solution can centrally restrict the creation of AWS resources in the development accounts.

A. Develop AWS Systems Manager templates that use an approved EC2 creation process. Use the approved Systems Manager templates to provision EC2 instances. This solution will not meet the requirement of the least development effort, as it involves developing and maintaining custom templates for EC2 creation, and relying on the staff to use the approved templates instead of enforcing a restriction2.

C. Configure an Amazon EventBridge rule that invokes an AWS Lambda function when an EC2 instance is created. Stop disallowed EC2 instance types. This solution will not meet the requirement of the least development effort, as it involves writing custom code for Lambda functions, and handling events and errors for EC2 creation3.

D. Set up AWS Service Catalog products for the staff to create the allowed EC2 instance types En-sure that staff can deploy EC2 instances only by using the Service Catalog products. This solution will not meet the requirement of the least development effort, as itinvolves setting up and managing Service Catalog products for EC2 creation, and ensuring that staff can only use Service Catalog products instead of enforcing a restriction.

Reference URL: https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_policies_scps.html

AWS Backup is a fully managed service that allows you to centralize and automate data protection of AWS services across compute, storage, and database. AWS Backup Vault Lock is an optional feature of a backup vault that can help you enhance the security and control over your backup vaults. When a lock is active in Compliance mode and the grace time is over, the vault configuration cannot be altered or deleted by a customer, account/data owner, or AWS. This ensures that your backups are available for you until they reach the expiration of their retention periods and meet the regulatory requirements.References:https://docs.aws.amazon.com/aws-backup/latest/devguide/vault-lock.html

it allows the company to deploy an application that processes large quantities of data in parallel and prevent groups of nodes from sharing the same underlying hardware. By running the EC2 instances in a spread placement group, the company can launch a small number of instances across distinct underlying hardware to reduce correlated failures. A spread placement group ensures that each instance is isolated from each other at the rack level. References:

Placement Groups

Spread Placement Groups

https://aws.amazon.com/blogs/big-data/manage-fine-grained-access-control-using-aws-lake-formation/

The best solution for this situation is option B, setting up AWS Global Accelerator with UDP listeners and endpoint groups in each Region. AWS Global Accelerator is a networking service that improves the availability and performance of internet applications by routing user requests to the nearest AWS Region [1]. It also improves the performance of UDP applications by providing faster, more reliable data transfers with lower latency and fewer packet losses. By setting up UDP listeners and endpoint groups in each Region, Global Accelerator will route traffic to the nearest Region for faster response times and a better user experience.

 it allows the EC2 instances to read and write rapidly and concurrently to shared storage across two Availability Zones. Amazon EFS provides a scalable, elastic, and highly available file system that can be mounted from multiple EC2 instances. Amazon EFS supports high levels of throughput and IOPS, and consistent low latencies. Amazon EFS also supports NFSv4 lock upgrading and downgrading, which enables high levels of concurrency. References:

Amazon EFS Features

Using Amazon EFS with Amazon EC2

This answer is correct because it meets the requirements of displaying a top-10 scoreboard in near-real time and offering the ability to stop and restore the game while preserving the current scores. Amazon ElastiCache for Redis is a blazing fast in-memory data store that provides sub-millisecond latency to power internet-scale real-time applications. You can use Amazon ElastiCache for Redis to set up an ElastiCache for Redis cluster to compute and cache the scores for the web application to display. You can use Redis data structures such as sorted sets and hashes to store and rank the scores of the players, and use Redis commands such as ZRANGE and ZADD to retrieve and update the scores efficiently. You can also use Redis persistence features such as snapshots and append-only files (AOF) to enable point-in-time recovery of your data, which can help you stop and restore the game while preserving the current scores.

Consider using the default aws/s3 KMS key if: You're uploading or accessing S3 objects using AWS Identity and Access Management (IAM) principals that are in the same AWS account as the AWS KMS key. You don't want to manage policies for the KMS key. Consider using a customer managed key if: You want to create, rotate, disable, or define access controls for the key. You want to grant cross-account access to your S3 objects. You can configure the policy of a customer managed key to allow access from another account.https://repost.aws/knowledge-center/s3-object-encryption-keys

An edge-optimized API Gateway is a way to create RESTful APIs that can access multiple DynamoDB tables through AWS Lambda functions. The edge-optimized API Gateway provides low latency and high performance by caching API responses at CloudFront edgelocations. The AWS Lambda functions can use the AWS SDK to query or scan the DynamoDB tables and return the data to the API Gateway. This solution meets all the requirements of the question, while the other options do not. References:

https://aws.amazon.com/blogs/compute/understanding-database-options-for-your-serverless-web-applications/

https://aws.amazon.com/getting-started/hands-on/build-serverless-web-app-lambda-apigateway-s3-dynamodb-cognito/module-3/

https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/best-practices.html

AWS CloudFormation is a service that helps you model and set up your AWS resources by using templates that describe all the resources that you want, such as Auto Scaling groups, load balancers, and databases. You can use AWS CloudFormation to deploy your infrastructure in an automated and consistent way across multiple environments and regions. You can also use AWS CloudFormation to update or delete your infrastructure as a single unit.

Reference URLs:

1 https://aws.amazon.com/cloudformation/

2 https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/Welcome.html

3 https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cfn-whatis-concepts.html

DynamoDB Accelerator (DAX) is a fully managed, highly available caching service built for Amazon DynamoDB. DAX delivers up to a 10 times performance improvement—from milliseconds to microseconds—even at millions of requests per second. DAX does all the heavy lifting required to add in-memory acceleration to your DynamoDB tables, without requiring developers to manage cache invalidation, data population, or cluster management. Now you can focus on building great applications for your customers without worrying about performance at scale. You do not need to modify application logic because DAX is compatible with existing DynamoDB API calls. This solution will meet the requirements with the least operational overhead, as it does not require any code development or manual intervention.

To reduce startup latency for Lambda functions that run on Java 11, Lambda SnapStart is a suitable solution. Lambda SnapStart is a feature that enables faster cold starts and lower outlier latencies for Java 11 functions. Lambda SnapStart uses a pre-initialized Java Virtual Machine (JVM) to run the functions, which reduces the initialization time and memory footprint. Lambda SnapStart does not incur any additional charges.

To store and access files that are 25 GB or larger across many EC2 instances and across multiple Availability Zones, Amazon Elastic File System (Amazon EFS) is a suitable solution. Amazon EFS provides a simple, scalable, elastic file system that can be mounted on multiple EC2 instances concurrently. Amazon EFS supports high availability and durability by storing data across multiple Availability Zones within a Region.

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/security-group-rules.html

it allows the compliance team to manage the KMS keys used for server-side encryption, thereby providing the necessary control over the encryption keys. Additionally, the use of the "aws:SecureTransport" condition on the bucket policy ensures that all connections to the S3 bucket are encrypted in transit.

https://aws.amazon.com/rds/aurora/global-database/

https://aws.amazon.com/blogs/architecture/using-amazon-aurora-global-database-for-low-latency-without-application-changes/

https://aws.amazon.com/rds/aurora/serverless/

This answer is correct because it meets the requirements of hosting a scalable web application that can handle large data transfers from different geographic regions. Amazon EC2 provides scalable compute capacity for hosting web applications. Auto Scaling can automatically adjust the number of EC2 instances based on the demand and traffic patterns. Amazon CloudFront is a content delivery network (CDN) that can cache static and dynamic content at edge locations closer to the users, reducing latency and improving performance. CloudFront can also use S3 Transfer Acceleration to speed up the transfers between S3 buckets and CloudFront edge locations.

Amazon EFS is a fully managed file system that can be mounted by multiple Linux instances in AWS and on premises through native protocols such as NFS and SMB. Amazon EFS has no minimum size requirements and can scale up and down automatically as files are added andremoved. Amazon EFS also supports high availability and durability by allowing multiple mount targets in different Availability Zones within a region. Amazon EFS meets all the requirements of the question, while the other options do not. References:

https://aws.amazon.com/efs/

https://docs.aws.amazon.com/wellarchitected/latest/performance-efficiency-pillar/storage-architecture-selection.html

https://aws.amazon.com/blogs/storage/from-on-premises-to-aws-hybrid-cloud-architecture-for-network-file-shares/

This answer is correct because it meets the requirements of securely migrating the existing data to AWS and satisfying the new regulation. AWS DataSync is a service that makes it easy to move large amounts of data online between on-premises storage and Amazon S3. DataSync automatically encrypts data in transit and verifies data integrity during transfer. AWS CloudTrail is a service that records AWS API calls for your account and delivers log files to Amazon S3. CloudTrail can log data events, which show the resource operations performed on or within a resource in your AWS account, such as S3 object-level API activity. By using CloudTrail to log data events, you can audit access at all levels of the stored data.

Kubernetes API requests within your cluster's VPC (such as node to control plane communication) use the private VPC endpoint.https://docs.aws.amazon.com/eks/latest/userguide/cluster-endpoint.html

it allows the company to simplify the on-premises backup infrastructure and reduce costs by eliminating the use of physical backup tapes. By setting up AWS Storage Gateway to connect with the backup applications using the iSCSI-virtual tape library (VTL) interface, the company can store backup data on virtual tapes in S3 or Glacier. This preserves the existing investment in the on-premises backup applications and workflows while leveraging AWS storage services. References:

AWS Storage Gateway

Tape Gateway

S3 Storage Lens is a cloud storage analytics feature that provides organization-wide visibility into object storage usage and activity across multiple AWS accounts in AWS Organizations. S3 Storage Lens can report the incomplete multipart upload object count as one of the metrics that it collects and displays on an interactive dashboard in the S3 console. S3 Storage Lens can also export metrics in CSV or Parquet format to an S3 bucket for further analysis. This solution will meet the requirements with the least operational overhead, as it does not require any code development or policy changes.

it allows the company to encrypt the Kubernetes secrets object in the EKS cluster with the least operational overhead. By enabling secrets encryption in the EKS cluster, the company can use AWS Key Management Service (AWS KMS) to generate and manage encryption keys for encrypting and decrypting secrets at rest. This is a simple and secure way to protect sensitive information in EKS clusters. References:

Encrypting Kubernetes secrets with AWS KMS

Kubernetes Secrets

Creating a peering connection between the VPCs allows the application's EC2 instances to communicate with the ElastiCache cluster directly and efficiently. This is the most cost-effective solution as it does not involve creating additional resources such as a Transit VPC, and it does not incur additional costs for traffic passing through the Transit VPC. Additionally, it is also more secure as it allows you to configure a more restrictive security group rule to allow inbound connection from only the application's security group.

https://aws.amazon.com/premiumsupport/knowledge-center/dynamodb-high-latency/

Amazon DynamoDB Accelerator (DAX) is a fully managed in-memory cache for DynamoDB that improves the performance of DynamoDB tables by up to 10 times and provides microsecond level of response time at any scale. It is compatible with DynamoDB API operations and requiresminimal code changes to use1. By configuring DAX for the new messages table, the solution can reduce the latency for reading new messages with minimal application changes.

B. Add DynamoDB read repticas to handle the increased read load. Update the application to point to the read endpoint for the read replicas. This solution will not work, as DynamoDB does not support read replicas as a feature. Read replicas are available for Amazon RDS, not for DynamoDB2.

C. Double the number of read capacity units for the new messages table in DynamoDB. Continue to use the existing DynamoDB endpoint. This solution will not meet the requirement ofreading new messages with aslittle latency as possible, as increasing the read capacity units will only increase the throughput of DynamoDB, not the performance or latency3.

D. Add an Amazon ElastiCache for Redis cache to the application stack. Update the application to point to the Redis cache endpoint instead of DynamoDB. This solution will not meet the requirement of minimal application changes, as adding ElastiCache for Redis will require significant code changes to implement caching logic, such as querying cache first, updating cache after writing to DynamoDB, and invalidating cache when needed.

Reference URL: https://aws.amazon.com/dynamodb/dax/

The number of instances in your Auto Scaling group can be driven by how long it takes to process a message and the acceptable amount of latency (queue delay). The solution is to use a backlog per instance metric with the target value being the acceptable backlog per instance to maintain.

it allows the solutions architect to create a separate organization for the research and development (R&D) business and move its AWS account to the new organization. By inviting the R&D AWS account to be part of the new organization after it has left the prior organization, the solutions architect can ensure that there is no overlap or conflict between the two organizations. The R&D AWS account can accept or decline the invitation to join the new organization. Once accepted, it will be subject to any policies and controls applied by the new organization. References:

Inviting an AWS Account to Join Your Organization

Leaving an Organization as a Member Account