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Comprehensive and Detailed Explanation From Exact Extract of AWS CloudOps Doocuments:

For high availability and fast failover, ElastiCache for Redis supports replication groups with Multi-AZ and automatic failover. CloudOps guidance states that a primary node can be paired with one or more replicas across multiple Availability Zones; if the primary fails, Redis automatically promotes a replica to primary in seconds, thereby minimizing RTO. This architecture maintains in-memory data continuity without waiting for backup restore operations. Backups (Options B and D) provide durability but require restore and re-warm procedures that increase RTO and may impact application latency. Switching engines (Option A) to Memcached does not provide Redis replication/failover semantics and would not inherently improve resilience for this use case. Therefore, creating a read replica in a different AZ and enabling Multi-AZ with automatic failover is the prescribed CloudOps pattern to increase resilience and achieve the lowest practical RTO for Redis caches.

Comprehensive and Detailed Explanation From Exact Extract of AWS CloudOps Documents:

The requirement is to alert before throttling occurs. For a DynamoDB table in provisioned capacity mode, throttling happens when demand approaches or exceeds provisioned throughput. CloudWatch provides direct table metrics such as ConsumedReadCapacityUnits and ProvisionedReadCapacityUnits (and related utilization signals). Creating an alarm on ConsumedReadCapacityUnits with a threshold set close to the table’s provisioned read capacity provides an early warning that the table is nearing its limit—before actual throttling prevents reads. The alarm can publish directly to the existing SNS topic so the operations team is notified proactively.

Option C and D focus on detecting throttling after it occurs by matching throttling exceptions in logs. That is reactive and violates “before throttled.” Option B (auto scaling) may reduce the likelihood of throttling, but it does not directly satisfy the alerting requirement and “scaling events” notifications are not a reliable proxy for “approaching throttle” (and may not fire early enough depending on scaling configuration). The simplest, most direct CloudOps approach is a CloudWatch alarm on consumption nearing provisioned capacity.

An alias record is the recommended Route 53 record type to map domain names (e.g., example.com) to AWS-managed resources such as an Application Load Balancer. Alias records are extension types of A or AAAA records that support AWS resources directly, providing automatic DNS integration and no additional query costs.

AWS documentation states:

“Use alias records to map your domain or subdomain to an AWS resource such as an Application Load Balancer, CloudFront distribution, or S3 website endpoint.”

A and AAAA records are used for static IP addresses, not load balancers. CNAME records cannot be used at the root domain (e.g., example.com). Thus, Option C is correct as it meets CloudOps networking best practices for scalable, managed DNS resolution to ALBs.

Comprehensive and Detailed Explanation From Exact Extract of AWS CloudOps Documents:

To ensure video files are cached at CloudFront edge locations after migrating the files to Amazon S3, CloudFront must be able to fetch those video objects directly from S3 as an origin. The most operationally straightforward pattern is to add S3 as a second origin and create a separate cache behavior that routes requests for video paths (for example, /video/* or /*.mp4) to the S3 origin. With this configuration, CloudFront caches the S3-served objects at edge locations according to the cache policy/headers, while the existing ALB origin continues serving dynamic application paths. This isolates static media delivery from the application tier and improves performance by maximizing cache hits at the edge.

Option A is not how CloudFront origin selection works: CloudFront does not “redirect” to S3 based on headers; it selects an origin per behavior. Option C (signed URLs) is an access-control mechanism and does not, by itself, ensure the objects are retrieved from S3 or cached correctly. Option D (origin groups) is for origin failover (primary/secondary) and does not provide path-based routing to ensure videos come from S3.

Comprehensive and Detailed Explanation From Exact Extract of AWS CloudOps Documents:

The correct answer is B because cross-account role assumption requires two explicit permissions. AWS CloudOps documentation states that the target role must trust the principal, and the principal must be allowed to call sts:AssumeRole.

In the member account, the role’s trust policy must list the IAM group ARN (or the identity account) as a trusted principal. In the identity account, the IAM group must have an inline or attached policy that allows the sts:AssumeRole action for the target role ARN. This dual configuration enables secure and controlled cross-account access.

Option A is incorrect because trust policies cannot be attached to IAM groups. Option C is incorrect because sts:PassRole is used for passing roles to AWS services, not for assuming roles. Option D is incorrect because roles do not grant permissions via inline policies to principals.

This approach aligns precisely with AWS CloudOps guidance for multi-account IAM design.

Comprehensive and Detailed Explanation From Exact Extract of AWS CloudOps Documents:

For users in eu-west-2 transferring large files to/from an S3 bucket in ap-southeast-2 over the public internet, S3 Transfer Acceleration is designed to improve performance by leveraging the AWS global edge network. With Transfer Acceleration enabled, users access the bucket via the acceleration endpoint. Requests enter AWS at the nearest edge location and then traverse the AWS backbone network to the bucket’s Region, which typically reduces latency variability and can improve throughput for long-distance transfers.

Option A is incorrect because access points do not “replicate destinations” in the way described, and an access point in another Region does not move data closer by itself. Option B is incorrect because Route 53 DNS routing does not accelerate data transfers; it only resolves names and (in this case) also incorrectly references S3 website endpoints (not appropriate for general large file transfer APIs). Option C is not valid as written because a single S3 access point cannot be “associated with both buckets,” and maintaining two buckets introduces synchronization/consistency overhead; it’s not the least-friction acceleration approach for direct internet users.

Comprehensive and Detailed Explanation From Exact Extract of AWS CloudOps Documents:

To secure inbound web traffic over HTTPS when using an Application Load Balancer, AWS CloudOps best practices recommend terminating TLS at the load balancer. This is achieved by attaching an SSL/TLS certificate directly to the ALB listener. Therefore, option B is required. By terminating HTTPS at the ALB, traffic between clients and the load balancer is encrypted, and the ALB can then forward traffic to backend EC2 instances using HTTP or HTTPS based on design requirements.

The certificate used for a public-facing retail website must be trusted by internet browsers. AWS Certificate Manager (ACM) public certificates are specifically designed for this purpose and are trusted by common browsers and operating systems. Therefore, option D is required. ACM manages certificate provisioning, renewal, and deployment automatically, which significantly reduces operational overhead.

Option A is incorrect because attaching certificates to each EC2 instance is unnecessary and does not scale well. Option C is incorrect because private certificates are intended for internal use cases and are not trusted by public browsers. Option E is incorrect because ACM-managed public certificates cannot be exported; they must be attached directly to supported AWS services such as ALBs.

This approach aligns with AWS CloudOps guidance for secure, scalable, and highly available HTTPS architectures.

The AWS Cloud Operations and Systems Manager documentation states that to use Session Manager privately within a VPC (without internet access), three interface VPC endpoints must be configured:

com.amazonaws.<region>.ssm – enables Systems Manager core API communication.

com.amazonaws.<region>.ec2messages – allows the agent to send and receive messages between EC2 and Systems Manager.

com.amazonaws.<region>.ssmmessages – enables real-time interactive communication for Session Manager connections.

These endpoints ensure secure, private connectivity over the AWS network, eliminating the need for public internet routing.

Endpoints for S3, Step Functions, or EC2 API (Options C, E, F) are not required for Session Manager functionality.

Thus, the correct combination is A, B, and D, aligning with AWS CloudOps best practices for secure, private Systems Manager access.

An alias record is the recommended Route 53 record type to map domain names (e.g., example.com) to AWS-managed resources such as an Application Load Balancer. Alias records are extension types of A or AAAA records that support AWS resources directly, providing automatic DNS integration and no additional query costs.

AWS documentation states:

“Use alias records to map your domain or subdomain to an AWS resource such as an Application Load Balancer, CloudFront distribution, or S3 website endpoint.”

A and AAAA records are used for static IP addresses, not load balancers. CNAME records cannot be used at the root domain (e.g., example.com). Thus, Option C is correct as it meets CloudOps networking best practices for scalable, managed DNS resolution to ALBs.

According to the AWS Cloud Operations and Elastic Load Balancing documentation, Application Load Balancer (ALB) supports multiple routing algorithms to distribute requests among targets:

Round robin (default)

Least outstanding requests (LOR)

Weighted random

When applications require session affinity, AWS recommends using “least outstanding requests” as the load balancing algorithm because it reduces latency, distributes load evenly, and ensures consistent target responsiveness during high traffic.

Using weighted random routing with sticky sessions can cause sessions to be routed inconsistently if one target’s capacity fluctuates, leading to session mismatches and application errors — especially when user sessions rely on instance-specific state.

Disabling cross-zone balancing (Option C) or adjusting deregistration delay (Option D) does not address routing inconsistency. Anomaly mitigation (Option B) protects against target performance degradation, not sticky-session misrouting.

Therefore, the correct solution is Option A — changing the target group’s routing algorithm to least outstanding requests ensures smoother, predictable session handling and resolves random application errors.