Design Resilient Architectures

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A financial clearinghouse processes sensitive transactional data in its primary AWS Region (us-east-1). The current architecture consists of an Amazon Aurora PostgreSQL-Compatible Edition database cluster and an application tier running on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The clearinghouse must implement a disaster recovery (DR) strategy in a secondary Region (us-west-2) to ensure business continuity. The DR solution must achieve a Recovery Point Objective (RPO) of less than 1 minute and a Recovery Time Objective (RTO) of less than 10 minutes, while minimizing ongoing compute costs. Which database and application deployment strategy should a solutions architect recommend to meet these requirements?

Deploy an Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In us-west-2, pre-deploy the ALB and an Auto Scaling group with the minimum capacity set to 1 instance. Configure Amazon Route 53 failover routing with health checks to direct traffic to the secondary Region, and automate the promotion of the secondary database cluster in the event of a primary Region failure.

Deploy an Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. Create a launch template for the EC2 instances in us-west-2. Write an AWS Lambda function triggered by Amazon CloudWatch alarms to create the ALB, provision the Auto Scaling group from scratch, and promote the secondary database cluster only when a regional failover is initiated.

Configure cross-region database replication using an Amazon RDS PostgreSQL Read Replica in us-west-2. Deploy a fully provisioned Auto Scaling group behind an ALB in us-west-2. Use Route 53 latency-based routing to distribute traffic. In the event of a disaster, manually promote the read replica to a primary database instance and update the application configuration files with the new endpoint.

Configure daily backups of the Aurora cluster in us-east-1 and copy the snapshots to us-west-2, storing them in Amazon S3 Glacier Flexible Retrieval to minimize storage costs. Maintain a warm standby EC2 fleet behind an ALB in us-west-2. In the event of a disaster, initiate an expedited retrieval of the latest snapshot, restore the database cluster, and update Route 53 routing records.

Cevabı ve açıklamayı göster

Cevap: Deploy an Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In us-west-2, pre-deploy the ALB and an Auto Scaling group with the minimum capacity set to 1 instance. Configure Amazon Route 53 failover routing with health checks to direct traffic to the secondary Region, and automate the promotion of the secondary database cluster in the event of a primary Region failure.

Cevap

The correct strategy uses Amazon Aurora Global Database to achieve an RPO of less than 1 second through storage-level replication. For the application tier, a Warm Standby approach (pre-deploying the Application Load Balancer and running a minimal Auto Scaling group capacity of 1 instance) ensures that the infrastructure is ready to accept traffic immediately and scale out, satisfying the 10-minute RTO. Route 53 failover routing with health checks automates the DNS switchover, and promoting the secondary Aurora cluster takes less than a minute.

Adım Adım Çözüm

Analyze the RPO requirement of less than 1 minute.

Identify that daily snapshots (which have a 24-hour RPO) and standard RDS read replicas (which can experience high replication lag under write-heavy loads) are unsuitable. Amazon Aurora Global Database uses storage-level, dedicated physical replication with typical lag of less than 1 second, meeting the RPO.

Choosing the replication technology that guarantees minimal data loss is the first step in disaster recovery planning.

Analyze the RTO requirement of less than 10 minutes.

Determine that a Pilot Light strategy (where compute resources like ALBs and Auto Scaling groups are created from scratch) is too slow to guarantee recovery within 10 minutes due to resource provisioning and instance bootstrapping times. A Warm Standby strategy (where the ALB is pre-deployed and a minimum compute capacity is already running) is required to ensure immediate availability and fast scaling.

Computing provisioning times directly impact the recovery time (RTO), requiring pre-warmed compute components.

Evaluate routing and failover automation.

Confirm that Amazon Route 53 failover routing with health checks provides automated DNS redirection to the secondary Region. The promotion of the Aurora Global Database secondary cluster to primary can be automated via AWS Systems Manager or Lambda to execute within minutes.

Automated failover reduces manual operational steps, ensuring the RTO threshold is not breached during stress events.

Anahtar Kavram

Disaster Recovery (DR) Strategies (Warm Standby vs. Pilot Light) and Cross-Region Replication with Aurora Global Database

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A real estate listing platform hosts its application on AWS using Amazon EC2 instances and an Amazon RDS for PostgreSQL DB instance. The platform needs to establish a cost-effective disaster recovery (DR) plan in a secondary Region. The company specifies a Recovery Point Objective (RPO) of $24$ hours and a Recovery Time Objective (RTO) of $4$ hours. The DR plan must minimize ongoing running costs. Which TWO configurations should a solutions architect recommend to meet these requirements at the lowest cost?

Geçerli olan tümünü seçin

Configure daily automated snapshots of the RDS DB instance and copy them to the destination Region.

Store an AWS CloudFormation template of the application tier in an Amazon S3 bucket in the destination Region to deploy resources on demand.

Export the database backups directly to Amazon S3 Glacier Deep Archive daily to minimize storage costs.

Create a cross-region RDS Read Replica and use Amazon Route 53 latency routing to automatically redirect write traffic during a failover.

Deploy a Warm Standby environment in the destination Region with all EC2 instances running at full capacity to ensure zero startup time.

Cevabı ve açıklamayı göster

Cevap: Configure daily automated snapshots of the RDS DB instance and copy them to the destination Region.; Store an AWS CloudFormation template of the application tier in an Amazon S3 bucket in the destination Region to deploy resources on demand.

Cevap

Configure daily automated snapshots of the RDS DB instance and copy them to the destination Region, and store an AWS CloudFormation template of the application tier in an Amazon S3 bucket in the destination Region to deploy resources on demand.

To meet an RPO of

24

hours and an RTO of

4

hours at the lowest cost, a Backup and Restore strategy is the ideal solution. Configuring daily automated snapshots of the database and copying them to the destination Region meets the

24

-hour RPO. Storing an AWS CloudFormation template in Amazon S3 in the secondary Region allows you to deploy the application's compute resources on demand within the

4

-hour window during a disaster, incurring no compute costs during normal operations.

Adım Adım Çözüm

Analyze the RTO, RPO, and budget requirements.

The target requirements are RPO =

24

hours, RTO =

4

hours, and the strategy must minimize ongoing costs.

An RPO of

24

hours and an RTO of

4

hours allow for a Backup and Restore strategy, which is the most cost-effective disaster recovery strategy since no compute resources run actively in the backup Region.

Select the database replication strategy that meets the RPO at the lowest cost.

Choose daily database snapshots copied cross-region.

Creating daily snapshots fits the

24

-hour RPO, and copying them to the secondary Region incurs only standard storage costs, which is far cheaper than running a replica database.

Select the compute provisioning method that meets the RTO at the lowest cost.

Choose on-demand provisioning using AWS CloudFormation templates stored in S3.

AWS CloudFormation can provision the application tier in minutes, easily meeting the

4

-hour RTO while incurring zero ongoing compute costs prior to a failover event.

Anahtar Kavram

Disaster Recovery strategies on AWS range from Backup & Restore (lowest cost, highest RTO/RPO) to Active-Active (highest cost, lowest RTO/RPO). A Backup & Restore approach utilizes offline resources like snapshots and infrastructure-as-code templates to minimize running costs.

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An organization has migrated a legacy internal API to run on Amazon EC2 instances in an Auto Scaling Group (ASG) behind an Application Load Balancer (ALB). The API service is bound to TCP port 5050 on the instances. After launching the new instances, the ALB reports all targets as unhealthy with a status of 502 Bad Gateway for client requests. The security group associated with the ALB allows traffic on port 443 from client networks. The instances are deployed in private subnets. Which configuration adjustments are required to restore service health and enable successful load balancing? (Select two.)

Geçerli olan tümünü seçin

Configure the security group of the EC2 instances to permit inbound TCP port 5050 traffic from the security group of the Application Load Balancer.

Update the ALB's target group settings to register targets on port 5050 and configure health checks to query the traffic port or port 5050.

Adjust the health check path in the target group to point to the default port 80 so that health monitoring is isolated from custom application ports.

Add a stateless rule to the Network Access Control List (Network ACL) of the instance subnets that redirects inbound TCP port 80 traffic to TCP port 5050.

Implement an Amazon Route 53 latency routing policy that redirects traffic directly to the individual EC2 instance IP addresses when the ALB health checks fail.

Cevabı ve açıklamayı göster

Cevap: Configure the security group of the EC2 instances to permit inbound TCP port 5050 traffic from the security group of the Application Load Balancer.; Update the ALB's target group settings to register targets on port 5050 and configure health checks to query the traffic port or port 5050.

Cevap

Configure the security group of the EC2 instances to allow inbound traffic on TCP port 5050 from the ALB's security group, and update the ALB's target group settings to register targets on port 5050 and configure health checks to query port 5050.

To resolve the 502 Bad Gateway errors, the Application Load Balancer must be able to successfully connect to the EC2 instances on their active service port. This requires two configurations: first, updating the target group to send both application traffic and health checks to port 5050; second, modifying the security group of the EC2 instances to allow inbound TCP traffic on port 5050 from the ALB's security group.

Adım Adım Çözüm

Ensure target group routing matches the application port

The target group is updated to register EC2 instances on port 5050, and the health check configuration is set to use the traffic port (5050) so that the ALB checks the actual service.

Since the API runs on port 5050, checking default port 80 will fail as no listener exists there.

Configure instance-level security groups to allow traffic from the load balancer

Inbound TCP port 5050 is allowed on the instances' security group, with the source set to the security group of the ALB.

The load balancer needs network-level access to forward client requests and health check probes to the instances on the application port.

Anahtar Kavram

Configuring target group port registration, health checks, and security group rules for custom ports behind an Application Load Balancer.

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A company hosts a stateful web application at the apex domain example.com. The primary environment is deployed in the us-east-1 Region behind an Application Load Balancer (ALB) and uses an Amazon RDS Multi-AZ DB instance. The disaster recovery (DR) environment is in the us-west-2 Region behind another ALB and uses a cross-Region RDS read replica. The company requires a warm standby DR strategy where the DR environment is scaled down but running. The failover to us-west-2 must happen automatically if the primary ALB or the database becomes unavailable. The company wants to use Route 53 DNS failover and needs to minimize the Recovery Time Objective (RTO) while avoiding split-brain data writes. How should the solutions architect configure this architecture?

Configure Route 53 Failover alias records at the apex domain pointing to the ALBs in both Regions, enabling Evaluate Target Health on both records. Ensure the primary ALB's health check endpoint queries the primary database's health, and establish a process to promote the us-west-2 RDS read replica if a failover occurs.

Configure Route 53 Latency alias records at the apex domain pointing to both ALBs, enabling Evaluate Target Health on both records. Rely on Route 53 to automatically shift user traffic to the us-west-2 Region if the database latency increases in us-east-1.

Configure Route 53 Failover alias records pointing to both ALBs. To minimize cost, keep the EC2 instances in the us-west-2 DR environment stopped, and configure an Amazon CloudWatch alarm on Route 53 health check failures to start the instances.

Configure Route 53 Failover alias records pointing to both ALBs. Rely on RDS Multi-AZ replication to automatically fail over the database to the us-west-2 Region, which will automatically update the DNS records.

Cevabı ve açıklamayı göster

Cevap: Configure Route 53 Failover alias records at the apex domain pointing to the ALBs in both Regions, enabling Evaluate Target Health on both records. Ensure the primary ALB's health check endpoint queries the primary database's health, and establish a process to promote the us-west-2 RDS read replica if a failover occurs.

Cevap

The correct answer uses Route 53 Failover routing with Alias records pointing to the ALBs at the apex domain. Evaluating target health allows Route 53 to dynamically switch regions based on ALB health status. The primary ALB's health check is configured to query the database, ensuring that database failure also triggers the DNS failover. Because cross-Region database replication is asynchronous and does not automatically fail over, the secondary read replica must be promoted to primary during the failover process.

Adım Adım Çözüm

Select the correct Route 53 routing policy for active-passive disaster recovery.

Determine that Route 53 Failover routing policy is required to direct all traffic to us-east-1 normally and fail over to us-west-2.

Failover routing is designed for active-passive setups, whereas policies like Latency routing act as active-active and would route normal write traffic to the read-only replica.

Identify how Route 53 can route the apex domain to ALBs with health check support.

Create Alias records pointing to the ALBs and set Evaluate Target Health to Yes.

CNAME records cannot be used at the zone apex. Route 53 Alias records resolve this restriction and allow Route 53 to inherit the health status of the ALB's target group without extra health check costs.

Configure the dependency between application health and database availability.

Ensure the ALB health check path queries database connectivity, and create a replica promotion plan.

If the database in us-east-1 fails, the ALB health check will fail, triggering Route 53 to redirect DNS queries to us-west-2. The read replica must then be promoted to allow writes.

Anahtar Kavram

Using Route 53 Failover Alias records with Evaluate Target Health for active-passive multi-region DR while managing database replica promotion.

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A company is developing a ticket booking application on AWS. When a customer purchases a ticket, the system must process the payment transaction and assign a seat. To avoid double-booking and payment discrepancies, the transaction messages must be processed in the exact order they are received. The company wants to decouple the front-end application from the back-end processing service.

Which solution meets these requirements with the least operational overhead?

Send the transaction messages to a standard Amazon SQS queue, and configure the back-end service to consume the messages.

Store the transaction messages in an Amazon DynamoDB table configured with provisioned capacity mode, and have the back-end service poll the table.

Send the transaction messages to an Amazon SQS FIFO queue, and configure the back-end service to consume the messages.

Stream the transaction messages to an Amazon Kinesis data stream configured with a single provisioned shard, and configure the back-end service to process the stream.

Cevabı ve açıklamayı göster

Cevap: Send the transaction messages to an Amazon SQS FIFO queue, and configure the back-end service to consume the messages.

Cevap

Send the transaction messages to an Amazon SQS FIFO queue, and configure the back-end service to consume the messages.

The correct answer is to use an Amazon SQS FIFO queue. FIFO (First-In-First-Out) queues guarantee that messages are processed in the exact order in which they are sent. This native capability meets the ordering requirement with zero additional application logic and minimal operational overhead, while successfully decoupling the front-end and back-end services.

Adım Adım Çözüm

Identify the core requirements of the system: decoupling the application components and maintaining a strict processing order of transactions.

Decoupling requires an asynchronous message queuing service (like Amazon SQS), and strict ordering requires First-In-First-Out (FIFO) delivery.

Decoupling ensures the front-end remains responsive during high load, while strict ordering prevents race conditions like double-booking.

Select the service that meets both requirements with the lowest operational overhead.

Amazon SQS FIFO queues natively handle message ordering and deduplication without requiring custom application logic or server management.

SQS is a fully managed service, making it the most operationally efficient choice compared to self-managed or more complex streaming solutions.

Anahtar Kavram

Using Amazon SQS FIFO queues to decouple components while ensuring strict first-in, first-out message ordering.

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A SaaS payroll application processes employee timesheet submissions. To ensure accurate cumulative tax and overtime calculations, all timesheet update events for any given employee must be processed in the exact order they are received. These events must be delivered to $2$ independent downstream microservices: a payroll calculation engine and a compliance audit system. The application experiences traffic spikes of up to $450$ events per second. Which solution meets these requirements with the least operational overhead?

Publish the events to an Amazon SNS Standard topic, and subscribe

2

Amazon SQS Standard queues to the topic, with

1

queue for each microservice. Use the employee ID as the MessageGroupID attribute to group messages.

Publish the events to an Amazon Kinesis Data Stream, using the employee ID as the partition key. Configure each microservice to consume events from the stream using the Kinesis Client Library (KCL) running on AWS Fargate.

Publish the events to an Amazon SNS FIFO topic, and subscribe

2

Amazon SQS FIFO queues to the topic, with

1

queue for each microservice. Enable the high-throughput FIFO feature on both the SNS topic and SQS queues, and use the employee ID as the Message Group ID.

Publish the events to an Amazon EventBridge custom event bus. Define rules to route the events to

2

Amazon SQS Standard queues, and configure the queues to use the MessageDeduplicationId attribute based on the employee ID.

Cevabı ve açıklamayı göster

Cevap: Publish the events to an Amazon SNS FIFO topic, and subscribe $2$ Amazon SQS FIFO queues to the topic, with $1$ queue for each microservice. Enable the high-throughput FIFO feature on both the SNS topic and SQS queues, and use the employee ID as the Message Group ID.

Cevap

Publish the events to an Amazon SNS FIFO topic and subscribe

2

Amazon SQS FIFO queues to it, enabling high-throughput FIFO on both the topic and queues, and using the employee ID as the Message Group ID.

The correct solution leverages a native AWS serverless messaging pattern for fan-out with strict ordering. By publishing events to an Amazon SNS FIFO topic and subscribing

2

Amazon SQS FIFO queues (one for each microservice), the architecture decouples the services and guarantees exactly-once processing and FIFO delivery. The employee ID acts as the Message Group ID to ensure sequential ordering per employee. Enabling high-throughput FIFO on both the SNS topic and SQS queues allows the application to scale beyond the default limit of

300

transactions per second to accommodate the peak traffic of

450

events per second with minimal operational overhead.

Adım Adım Çözüm

Select a message fan-out service that supports ordered delivery.

Amazon SNS FIFO is selected to deliver events to multiple downstream queues while preserving strict first-in, first-out ordering.

Standard SNS topics do not guarantee message order and cannot fan out to SQS FIFO queues with order preservation.

Configure the logical grouping key for ordering.

Assign the employee ID as the Message Group ID on the messages published to the SNS FIFO topic.

This guarantees that all timesheet updates for a single employee are processed sequentially in the order received, while allowing concurrent processing across different employees.

Provision and subscribe target queues for downstream microservices.

2

SQS FIFO queues are subscribed to the SNS FIFO topic, with

1

queue dedicated to each microservice.

Dedicated queues decouple the downstream consumers and ensure each microservice receives all published events independently.

Configure throughput capacity to support traffic spikes.

Enable high-throughput FIFO on the SNS FIFO topic and both SQS FIFO queues.

By default, SQS FIFO queues support up to

300

transactions per second (without batching). The expected traffic peaks at

450

events per second, requiring high-throughput FIFO to prevent throttling.

Anahtar Kavram

Serverless event fan-out with guaranteed ordering using SNS FIFO, SQS FIFO, and High-Throughput FIFO.

Tahmini Süre:3m 0s

Soru 307Soru →

A company runs a car rental reservation portal in a single AWS Region. The application uses an Amazon RDS for MySQL DB instance. The company needs to establish a disaster recovery (DR) strategy in a secondary Region. The strategy must meet a Recovery Point Objective (RPO) of 24 hours and a Recovery Time Objective (RTO) of 4 hours. Which solution meets these requirements at the lowest cost?

Deploy a warm standby database replica in the secondary Region with a continuously running, scaled-down RDS DB instance to guarantee immediate database failover.

Configure automated daily snapshots of the RDS DB instance and copy them to the secondary Region. In the event of a disaster, use AWS CloudFormation to deploy the application resources and restore the database from the copied snapshot.

Create an RDS Read Replica in the secondary Region, and configure Amazon Route 53 latency routing to automatically promote the replica and redirect database write traffic during a failover.

Configure daily database backups, store them in Amazon S3 Glacier Flexible Retrieval in the secondary Region, and use standard retrieval to restore the database in the event of a disaster.

Cevabı ve açıklamayı göster

Cevap: Configure automated daily snapshots of the RDS DB instance and copy them to the secondary Region. In the event of a disaster, use AWS CloudFormation to deploy the application resources and restore the database from the copied snapshot.

Cevap

The Backup and Restore strategy using daily cross-region RDS snapshots and AWS CloudFormation templates is the most cost-effective option because it incurs zero active database or compute charges in the secondary Region. The daily snapshots satisfy the 24-hour Recovery Point Objective (RPO), and restoring the database and infrastructure can be completed within the 4-hour Recovery Time Objective (RTO).

Adım Adım Çözüm

Analyze RPO and RTO requirements to determine the appropriate DR strategy.

An RPO of 24 hours indicates daily data loss is acceptable, pointing to daily backups/snapshots. An RTO of 4 hours allows enough time to provision infrastructure and restore the database from a backup.

Matching business continuity requirements with the correct DR strategy prevents over-engineering and minimizes costs.

Evaluate the cost of different DR options.

Backup and Restore (storing snapshots) is the most cost-effective strategy since it incurs only storage costs until a disaster occurs. Warm Standby and Read Replicas incur active, continuous compute and database instance costs.

The question asks for the lowest cost solution that meets the requirements.

Verify technical feasibility and correctness.

Daily snapshots meet the 24-hour RPO. Restoring RDS from a snapshot and launching resources via AWS CloudFormation can be easily completed within 4 hours. S3 Glacier Flexible Retrieval is ruled out because its 3-5 hour retrieval delay alone risks violating the 4-hour RTO.

Ensures the selected low-cost solution is technically capable of achieving the RTO and RPO targets.

Anahtar Kavram

Disaster Recovery (DR) strategies on AWS vary in cost and recovery times. Backup and Restore is the most cost-effective DR strategy for workloads that can tolerate an RTO and RPO of several hours, as it does not require running active compute or database instances in the recovery region.

Tahmini Süre:1m 0s

Soru 308Soru →

A company hosts a critical global multiplayer gaming backend in us-east-1. The backend utilizes Amazon Aurora MySQL for player profiles, session states, and game configuration data, and an Application Load Balancer (ALB) with Amazon ECS Fargate for the web API layer. The company needs to establish a Disaster Recovery (DR) strategy in us-west-2 with a Recovery Time Objective (RTO) of less than $15$ minutes and a Recovery Point Objective (RPO) of less than $1$ minute. They also want to minimize monthly standby running costs. Which of the following architectures meets these requirements?

Configure Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In us-west-2, deploy the ECS Fargate service with the desired task count set to

0

. Configure Amazon Route 53 failover routing with health checks. During a failover event, promote the secondary Aurora cluster to primary, scale the ECS Fargate task count to the required capacity, and update the DNS records.

Deploy an Amazon Aurora MySQL database with a cross-region Read Replica in us-west-2. Configure the ECS Fargate service in us-west-2 to run at full capacity. Use Amazon Route 53 latency-based routing to automatically failover application write traffic to the replica in us-west-2 if the primary region becomes unhealthy.

Implement a Backup and Restore strategy. Set up AWS Backup to take hourly snapshots of the Aurora database and copy them to Amazon S3 Glacier Flexible Retrieval in us-west-2. In us-west-2, keep the ECS Fargate task definition registered. Upon disaster, retrieve the backup from S3 Glacier using standard retrieval, restore the database, and launch the ECS Fargate tasks.

Configure a Pilot Light strategy. Scale the ECS Fargate service in us-west-2 to

0

tasks. To minimize database standby costs, stop the secondary Aurora DB instance in the secondary region. Configure an AWS Lambda function to start the instance during failover, expecting the database to start instantly and serve traffic with a recovery time of under

2

minutes.

Cevabı ve açıklamayı göster

Cevap: Configure Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In us-west-2, deploy the ECS Fargate service with the desired task count set to $0$ . Configure Amazon Route 53 failover routing with health checks. During a failover event, promote the secondary Aurora cluster to primary, scale the ECS Fargate task count to the required capacity, and update the DNS records.

Cevap

Configure Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In us-west-2, deploy the ECS Fargate service with the desired task count set to

0

The configuration using Amazon Aurora Global Database and scaling ECS Fargate tasks to

0

in the secondary region represents a Pilot Light strategy. Aurora Global Database keeps the primary and secondary databases synchronized via storage-level replication with sub-second replication latency, meeting the

1

-minute RPO. Since no Fargate tasks are running in the secondary region during normal operations, standby compute costs are minimized. During a disaster, promoting the Aurora secondary cluster takes less than a minute, and scaling up the ECS Fargate tasks to full capacity takes a few minutes, which easily meets the

15

-minute RTO requirement.

Adım Adım Çözüm

Analyze RPO requirements.

To meet an RPO of less than

1

minute, database changes must be replicated to the secondary region continuously. Amazon Aurora Global Database uses storage-based replication with a typical latency of less than

1

second, easily meeting this constraint.

Choosing the replication technology first ensures the data loss window (RPO) is minimized.

Analyze RTO and standby cost requirements.

To minimize standby running costs, compute resources (ECS Fargate tasks) in the disaster recovery region should be scaled to

0

when idle. Promoting an Aurora Global Database secondary cluster takes under

1

minute, and provisioning ECS Fargate containers takes

2

3

minutes. This easily fits within the

15

-minute RTO.

This establishes a Pilot Light strategy, which has minimal running standby costs while still satisfying the RTO.

Evaluate failover and DNS routing.

Using Route 53 active-passive failover routing policy allows traffic redirection once health checks fail. During failover, the secondary Aurora cluster is promoted to primary (becoming read-write), and the ECS Fargate tasks are scaled up to match the production workload.

A clean failover orchestration guarantees consistent application state and traffic redirection.

Anahtar Kavram

Disaster recovery (DR) strategies on AWS involve trading off cost (standby resources) against Recovery Time Objective (RTO) and Recovery Point Objective (RPO). For RPO <

1

minute and RTO <

15

minutes with minimized costs, a Pilot Light strategy using Aurora Global Database (with secondary cluster running a minimal reader) and scaled-down compute (ECS Fargate task count set to

0

) is the most optimal architecture.

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A company hosts a security-hardened metadata retrieval service on a fleet of Amazon EC2 instances in an Auto Scaling group (ASG) behind an Application Load Balancer (ALB). The application listens on TCP port $8443$ , while a local diagnostic agent listens on TCP port $8080$ to respond with node status. The solutions architect configures the ALB target group with default health check settings. Custom Network ACLs (NACLs) and security groups are applied to the EC2 instances. During testing, the ALB marks all registered instances as unhealthy, even though local status checks on port $8080$ succeed. Additionally, after a recent failover to a secondary region due to network latency, Route 53 fails to route clients back to the primary region's ALB after its instances recover.

Which combination of configuration changes should the solutions architect implement to resolve these issues? (Select two.)

Geçerli olan tümünü seçin

Modify the target group health check settings to query port

8080

instead of the default traffic port.

Add an outbound rule to the subnet network ACL to allow outbound traffic to the ALB subnets on ephemeral ports

1024-65535

Configure the target group health check settings to query port

80

to verify baseline web server socket availability.

Add an outbound rule to the EC2 security group allowing traffic to the ALB security group on ephemeral ports

1024-65535

Update the Route 53 latency routing policy to failover using TTL records without configuring health checks.

Cevabı ve açıklamayı göster

Cevap: Modify the target group health check settings to query port $8080$ instead of the default traffic port.; Add an outbound rule to the subnet network ACL to allow outbound traffic to the ALB subnets on ephemeral ports $1024-65535$ .

Cevap

To resolve the health check failure, update the target group health check settings to query port

8080

instead of the default traffic port, and add an outbound rule to the stateless subnet network ACL to allow return traffic to the ALB subnets on ephemeral ports

1024-65535

The diagnostic agent runs on port

8080

, so the target group health check port must be explicitly updated to query port

8080

instead of defaulting to the application traffic port of

8443

. Additionally, since network ACLs are stateless, an outbound rule must be added to the subnet network ACL to allow return traffic from the EC2 instances to the ALB subnets on ephemeral ports

1024-65535

Adım Adım Çözüm

Analyze the health check port configuration.

Identify that the health check is defaulting to the application traffic port (

8443

) instead of the diagnostic agent port (

8080

The target group must be modified to query port

8080

explicitly so that the health check reaches the correct service.

Evaluate network access control lists (NACLs) and security group rules.

Recognize that the stateless subnet network ACL blocks return outbound traffic to the ALB because there is no rule allowing outbound traffic on ephemeral ports.

A stateless network ACL requires explicit rules for both inbound and outbound traffic paths, unlike stateful security groups.

Formulate the correction for the network ACL.

Create an outbound network ACL rule allowing traffic to the ALB subnets on ephemeral ports

1024-65535

This allows return packets from the EC2 instances to reach the ALB subnets and satisfy the health check.

Anahtar Kavram

Auto Scaling and Elastic Load Balancing health checks, stateless vs stateful network filtering, and Route 53 failover health check requirements.

Tahmini Süre:2m 0s

Soru 310Soru →

A financial services company hosts a credit-scoring application in the eu-west-1 Region. The application uses Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB), and a multi-node Amazon Aurora PostgreSQL DB cluster. The company needs to implement a disaster recovery (DR) strategy in the us-east-1 Region with a Recovery Time Objective (RTO) of $15$ minutes and a Recovery Point Objective (RPO) of $2$ minutes. The solution must minimize ongoing operational costs in the secondary Region during normal operations. Which configuration should a solutions architect recommend to meet these requirements?

Set up an Amazon RDS PostgreSQL DB instance in eu-west-1 with a cross-region read replica in us-east-1. In us-east-1, deploy an ALB and an Auto Scaling group with the desired capacity set to

0

. Configure Amazon Route 53 with active-passive failover routing to automatically promote the cross-region read replica and scale up the Auto Scaling group when health checks fail.

Configure daily snapshots of the Aurora DB cluster and copy them to an Amazon S3 bucket in us-east-1, configured to transition snapshots to Amazon S3 Glacier Flexible Retrieval. In us-east-1, deploy an ALB and an Auto Scaling group with a desired capacity of

0

. During failover, retrieve the snapshot from Glacier, restore the database, and scale up the Auto Scaling group.

Configure an Aurora Global Database with the primary DB cluster in eu-west-1 and a secondary DB cluster in us-east-1. In us-east-1, deploy an ALB and an Auto Scaling group with the minimum and desired capacity set to

0

. During failover, promote the secondary Aurora DB cluster to primary and update the Auto Scaling group capacity to launch the EC2 instances.

Configure an Aurora Global Database with the primary DB cluster in eu-west-1 and a secondary DB cluster in us-east-1. In us-east-1, deploy an ALB and a scaled-down Auto Scaling group with the minimum capacity set to

2

EC2 instances to run the application at minimal capacity. During failover, promote the secondary database cluster and scale out the Auto Scaling group.

Cevabı ve açıklamayı göster

Cevap: Configure an Aurora Global Database with the primary DB cluster in eu-west-1 and a secondary DB cluster in us-east-1. In us-east-1, deploy an ALB and an Auto Scaling group with the minimum and desired capacity set to $0$ . During failover, promote the secondary Aurora DB cluster to primary and update the Auto Scaling group capacity to launch the EC2 instances.

Cevap

0

. During failover, promote the secondary Aurora DB cluster to primary and update the Auto Scaling group capacity to launch the EC2 instances.

The correct architecture is a Pilot Light disaster recovery strategy using Aurora Global Database. Aurora Global Database replicates data asynchronously across AWS Regions with a typical latency of less than

1

second, easily meeting the

2

-minute RPO. Since the business requires cost minimization under normal conditions and allows up to

15

minutes for recovery (RTO), keeping the Auto Scaling group in the secondary Region at a desired capacity of

0

ensures no EC2 compute charges are incurred until a disaster occurs. During failover, the secondary Aurora cluster can be promoted to primary in under a minute, and the Auto Scaling group can quickly launch EC2 instances to begin serving traffic within the

15

-minute window.

Adım Adım Çözüm

Identify the database replication technology that meets the RPO requirement of

2

minutes.

Aurora Global Database provides sub-second cross-region replication, which easily satisfies the

2

-minute RPO.

Alternative strategies like daily snapshots copied to Amazon S3 would yield an RPO of up to

24

hours, which fails the business requirements.

Determine the minimum compute capacity in the secondary Region that satisfies the RTO of

15

minutes while minimizing costs.

An Auto Scaling group with a desired capacity of

0

instances incurs zero EC2 costs during normal operations and can spin up instances within a few minutes.

This Pilot Light setup meets the

15

-minute RTO upon failover, making it more cost-effective than running instances continuously (Warm Standby).

Analyze the failover automation and network routing capabilities.

Aurora Global Database can be promoted to a standalone primary cluster in less than a minute, fitting well within the

15

-minute RTO.

DNS routing policies alone cannot automatically perform database promotion, meaning a scripted or manual orchestration process is necessary to complete the failover.

Anahtar Kavram

Disaster Recovery strategies (Pilot Light vs. Warm Standby) and database cross-region replication capabilities.

Tahmini Süre:2m 0s

Soru 311Soru →

A company is designing a new microservices-based application on AWS. When an order is placed, the order details must be sent to two separate downstream systems: an inventory management service and a shipping coordination service. The orders must be processed by both services in the exact chronological sequence they were placed. Which combination of services should a solutions architect recommend to decouple these systems while preserving the message order? (Select TWO.)

Geçerli olan tümünü seçin

Amazon SQS FIFO queues to buffer messages for each downstream service

Amazon SNS FIFO topics to fan out the messages to the queues

Amazon SQS Standard queues to queue messages for each downstream service

Amazon RDS Read Replicas to replicate the order database for downstream services

Amazon Route 53 Latency Routing to route messages to the closest downstream service

Cevabı ve açıklamayı göster

Cevap: Amazon SQS FIFO queues to buffer messages for each downstream service; Amazon SNS FIFO topics to fan out the messages to the queues

Cevap

Amazon SQS FIFO queues and Amazon SNS FIFO topics are the correct services to decouple the components and preserve the message order.

To decouple microservices while ensuring that messages are sent to multiple endpoints (fan-out) and processed in the exact chronological sequence, Amazon SNS FIFO topics and Amazon SQS FIFO queues must be used in combination. SNS FIFO topics manage ordering during distribution, and SQS FIFO queues ensure that consumers pull messages in the correct sequence.

Adım Adım Çözüm

Identify the decoupling and fan-out requirements.

The application needs to distribute messages to multiple distinct downstream services (fan-out pattern).

Amazon SNS is the standard service on AWS to achieve fan-out messaging to multiple consumers.

Determine the message ordering constraints.

The messages must be processed in the exact order they are received.

Standard SQS and SNS do not guarantee strict ordering. FIFO (First-In-First-Out) features must be used for both SNS and SQS to preserve end-to-end chronological sequence.

Combine SNS FIFO and SQS FIFO.

The solutions architect should deploy an Amazon SNS FIFO topic that publishes to Amazon SQS FIFO queues attached to each downstream microservice.

This architecture decouples the services, supports fan-out, and preserves message order.

Anahtar Kavram

Decoupling message-driven architectures while preserving strict message ordering using SNS and SQS FIFO configurations.

Tahmini Süre:1m 30s

Soru 312Soru →

A company is hosting a specialized IoT data receiver application on Amazon EC2 instances within an Auto Scaling group (ASG) behind an Application Load Balancer (ALB). The application receives data streams on port 5001, but the application's internal diagnostics and health status endpoint runs on port 8081. After launching the instances, the ALB target group reports all EC2 instances as unhealthy, and no traffic is forwarded to them, even though local logs show the application is running normally. Which of the following configuration changes will resolve this issue?

Modify the Application Load Balancer target group's health check configuration to override the port and specify port 8081.

Update the Application Load Balancer listener rule to forward incoming traffic to port 8081, and set the target group's health check port to 'traffic-port'.

Add an inbound rule to the security group associated with the EC2 instances to allow port 8081, and configure the subnet's Network ACL with an inbound rule for port 8081 without adding a corresponding outbound rule.

Configure Amazon Route 53 latency routing to distribute traffic directly to the Auto Scaling group instances' public IP addresses, relying on Route 53 to failover during unhealthy states.

Cevabı ve açıklamayı göster

Cevap: Modify the Application Load Balancer target group's health check configuration to override the port and specify port 8081.

Cevap

Modify the Application Load Balancer target group's health check configuration to override the port and specify port 8081.

The correct solution is to modify the Application Load Balancer target group's health check configuration to override the port and specify port 8081. By default, target groups perform health checks on the port where they receive traffic (the 'traffic-port', which is port 5001). Since the application's health endpoint is hosted on port 8081, the health check requests sent to port 5001 fail, marking the instances as unhealthy. Overriding the health check port to 8081 allows the Application Load Balancer to query the correct endpoint while client traffic is successfully routed to port 5001.

Adım Adım Çözüm

Analyze the port configuration of the application and the health check endpoint.

The application listens for data on port 5001, but diagnostics run on port 8081.

To understand why health checks are failing under the default settings.

Determine the default behavior of the Elastic Load Balancing target group health check.

By default, the health check queries the 'traffic-port', which is port 5001.

Since the diagnostics endpoint is not on port 5001, the health check fails, marking the targets as unhealthy.

Identify the correct configuration change to target the health endpoint.

Override the target group's health check port setting to explicitly use port 8081.

This allows the load balancer to query the correct port for health checks while keeping the listener forwarding data traffic to port 5001.

Anahtar Kavram

Configuring custom health check ports in Elastic Load Balancing target groups to align with application-specific health endpoints.

Tahmini Süre:2m 0s

Soru 313Soru →

A global healthcare compliance SaaS provider hosts its core patient-tracking application on Amazon EC2 instances in an Auto Scaling group (ASG) behind an Application Load Balancer (ALB). The application database is hosted on Amazon Aurora MySQL-Compatible Edition. The application is currently deployed in the $us-east-1$ Region. The provider needs to design a cross-region disaster recovery (DR) solution in the $us-west-2$ Region. The DR solution must meet a Recovery Time Objective (RTO) of $15$ minutes and a Recovery Point Objective (RPO) of $2$ minutes, while minimizing ongoing infrastructure running costs in the secondary Region during normal operations. Which architecture will meet these requirements at the lowest cost?

Configure Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. Deploy an ALB and an ASG in us-west-2 with the desired capacity set to 1 EC2 instance. Configure Route 53 failover routing with health checks. Use an AWS Systems Manager (SSM) Automation runbook to promote the secondary Aurora cluster and scale up the ASG during failover.

Configure Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. Deploy an ALB and an ASG in us-west-2 with the desired capacity set to 0. Store an AWS CloudFormation template for the EC2 and ALB resources in Amazon S3. During a failover event, deploy the CloudFormation stack to provision the application tier, promote the secondary Aurora cluster, and update Route 53 routing.

Configure Route 53 Latency routing with health checks to distribute traffic between us-east-1 and us-west-2. Deploy the active EC2 application tier in both Regions. In us-west-2, deploy an Aurora MySQL Read Replica. If the primary Region fails, Route 53 will automatically direct all write traffic to the us-west-2 Read Replica to maintain write availability without database promotion overhead.

Perform hourly snapshots of the Aurora cluster in us-east-1 and copy them to an Amazon S3 Glacier Flexible Retrieval vault in us-west-2. In the event of a disaster, trigger an AWS Lambda function to initiate a Standard retrieval of the latest snapshot, restore the database to a new Aurora cluster in us-west-2, and spin up the EC2 application tier using a pre-configured AMI.

Cevabı ve açıklamayı göster

Cevap: Configure Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. Deploy an ALB and an ASG in us-west-2 with the desired capacity set to 1 EC2 instance. Configure Route 53 failover routing with health checks. Use an AWS Systems Manager (SSM) Automation runbook to promote the secondary Aurora cluster and scale up the ASG during failover.

Cevap

The correct architecture uses Amazon Aurora Global Database for real-time cross-region replication, combined with a scaled-down Warm Standby EC2 application tier (desired capacity set to 1 instance) in the recovery Region, managed via Route 53 failover routing and AWS Systems Manager (SSM) Automation runbooks.

The architecture that configures Amazon Aurora Global Database alongside a Warm Standby application tier (desired capacity of 1 EC2 instance) is the only option that meets both RPO and RTO requirements while minimizing costs. Aurora Global Database replicates data asynchronously within seconds, satisfying the

2

-minute RPO. Having a single pre-running EC2 instance ensures the application stack is initialized, allowing an SSM Automation runbook to promote the database and scale out the ASG in under

10

minutes, satisfying the

15

-minute RTO. Keeping the ASG at

1

instance during normal operations minimizes running costs compared to a fully provisioned Active-Active setup.

Adım Adım Çözüm

Evaluate the database replication strategy to meet the

2

-minute RPO.

Amazon Aurora Global Database provides asynchronous replication with typical latency of less than

1

second, satisfying the RPO. Hourly snapshots or backup-restore methods are ruled out because they cannot guarantee data loss under

2

minutes.

Choosing a replication method that guarantees an RPO under

2

minutes is the primary constraint for the data tier.

Evaluate the compute tier deployment strategy to meet the

15

-minute RTO.

A Warm Standby strategy with a minimum of

1

running EC2 instance ensures the OS, dependencies, and configuration are active and running. A Pilot Light strategy with

0

running instances requires cold starts, CloudFormation stack deployment, and bootstrapping, which exceed the

15

-minute RTO limit.

The RTO is highly aggressive for cross-region failover, requiring pre-warmed compute resources that only need to scale out rather than be provisioned from scratch.

Assess the failover automation and routing mechanism.

Route 53 active-passive failover routing policies dynamically redirect traffic based on health checks. AWS Systems Manager (SSM) Automation handles the orchestration of promoting the secondary Aurora cluster to primary and scaling up the EC2 Auto Scaling group.

Manual intervention takes too long and introduces errors. An automated runbook is required to meet the 15-minute RTO.

Anahtar Kavram

Cross-Region Disaster Recovery Strategies (Warm Standby vs. Pilot Light)

Tahmini Süre:3m 0s

Soru 314Soru →

A company runs a wellness tracking application. The backend API is hosted on Amazon EC2 instances in an Auto Scaling group (ASG) behind an Application Load Balancer (ALB). The API processes requests on TCP port 8443. Currently, clients cannot connect to the backend, and the instances are being marked as unhealthy by the target group, leading to continuous instance replacement by the ASG. The network configuration uses private subnets for the EC2 instances and public subnets for the ALB.

Which two configurations should a solutions architect verify to resolve the health check failures and ensure proper traffic flow? (Select two.)

Geçerli olan tümünü seçin

Ensure that the target group health check port is configured to use port 8443 or the traffic port instead of defaulting to port 80.

Configure the EC2 instance security group to allow inbound traffic on TCP port 8443 from the security group of the Application Load Balancer.

Set the target group health check port to port 80 so that health checks do not consume processing capacity on the application port 8443.

Add an outbound rule to the EC2 instance security group allowing ephemeral port traffic to the Application Load Balancer to permit return packets.

Set up an Amazon Route 53 latency-based routing policy pointing directly to individual EC2 instances to distribute traffic and bypass the Application Load Balancer during high-latency periods.

Cevabı ve açıklamayı göster

Cevap: Ensure that the target group health check port is configured to use port 8443 or the traffic port instead of defaulting to port 80.; Configure the EC2 instance security group to allow inbound traffic on TCP port 8443 from the security group of the Application Load Balancer.

Cevap

Verifying that the target group health check is set to port 8443 or the traffic port, and configuring the EC2 instance security group to allow inbound traffic on port 8443 from the Application Load Balancer security group.

The Application Load Balancer routes traffic to targets based on target group settings. Since the backend service is listening on custom TCP port 8443, the target group health check port must be configured to query port 8443 (or use the traffic port) so that health checks are sent to the correct active port. By default, health checks are sent to port 80, which will fail if no service is listening there. Additionally, because the EC2 instances are in private subnets and receive traffic from the ALB, the security group associated with the EC2 instances must allow inbound traffic on port 8443 from the ALB's security group to permit both user traffic and health check probes.

Adım Adım Çözüm

Analyze the port configuration of the application service and the load balancer target group.

Identify that the application processes traffic on port 8443, but target group health checks default to port 80.

Health checks sent to a port with no active service will fail, causing the ASG to terminate instances.

Examine security group settings between the ALB and the EC2 instances.

Determine that the instances must allow inbound traffic on port 8443 specifically from the ALB security group.

This permits the ALB to perform health check probes and forward application traffic to the backend instances.

Validate security group statefulness.

Recognize that return traffic does not require outbound security group rules.

Security groups track connections and state, so return traffic on ephemeral ports is allowed automatically.

Anahtar Kavram

Configuring health checks and security groups for Application Load Balancers with custom ports.

Soru 315Soru →

A corporate training platform hosts its web application in a single AWS Region. The platform's database is stored on Amazon RDS for PostgreSQL, and application data is on Amazon EBS volumes. The company wants to set up a cost-effective Backup and Restore disaster recovery (DR) strategy in a secondary Region. The company can tolerate a $24$ -hour Recovery Point Objective (RPO) and a $24$ -hour Recovery Time Objective (RTO). Which combination of actions will meet these requirements at the lowest cost? (Select TWO.)

Geçerli olan tümünü seçin

Configure daily backups of Amazon Elastic Block Store (Amazon EBS) volumes and Amazon RDS DB instances, and copy the snapshots to the secondary AWS Region.

Use AWS CloudFormation templates to deploy the application infrastructure in the secondary AWS Region during a disaster, and restore the databases from the copied snapshots.

Deploy scaled-down Amazon EC2 instances in a Pilot Light configuration in the secondary AWS Region and expect them to handle full production traffic immediately without scaling up.

Create an Amazon RDS Read Replica in the secondary AWS Region and configure it to automatically perform Multi-AZ failover for the primary database.

Store all database backups in Amazon S3 Glacier Flexible Retrieval and use standard retrieval to recover data within a

5

-minute recovery time window.

Cevabı ve açıklamayı göster

Cevap: Configure daily backups of Amazon Elastic Block Store (Amazon EBS) volumes and Amazon RDS DB instances, and copy the snapshots to the secondary AWS Region.; Use AWS CloudFormation templates to deploy the application infrastructure in the secondary AWS Region during a disaster, and restore the databases from the copied snapshots.

Cevap

The correct strategy is to configure daily backups of EBS volumes and RDS instances, copy them to a secondary region, and deploy the application infrastructure on-demand using CloudFormation while restoring the databases from those snapshots when a disaster occurs.

For a

24

-hour RPO and RTO, a Backup and Restore strategy is the most cost-effective option. The two correct options accomplish this by first setting up daily backups of EBS volumes and RDS databases and copying them to a secondary region (satisfying the

24

-hour RPO), and second, deploying the architecture on-demand during a disaster using AWS CloudFormation and restoring the databases from the copied snapshots (satisfying the

24

-hour RTO without incurring compute costs during normal operations).

Adım Adım Çözüm

Evaluate the RPO and RTO requirements to select the appropriate disaster recovery (DR) pattern.

An RPO of

24

hours and an RTO of

24

hours point to a Backup and Restore strategy as the most cost-effective solution.

Backup and Restore has the lowest cost because it does not require active compute or fully-scaled databases to run in the disaster recovery region during normal operations.

Identify the mechanism for meeting the

24

-hour RPO.

Daily snapshots of EBS volumes and RDS DB instances are copied to the secondary Region.

By taking and copying snapshots every

24

hours, data loss is capped at a maximum of

24

hours, satisfying the RPO.

Identify the mechanism for meeting the

24

-hour RTO.

Using CloudFormation to provision the network and compute resources, then restoring the database from the copied snapshots.

Rebuilding the environment on-demand easily fits within the generous

24

-hour RTO window, keeping disaster recovery costs minimal.

Anahtar Kavram

Backup and Restore Disaster Recovery Strategy

Soru 316Soru →

A company hosts a specialized analytics platform on Amazon EC2 instances within an Auto Scaling group (ASG) behind an Application Load Balancer (ALB). The application listens for HTTPS traffic on TCP port 8443. To monitor the application's internal status, a custom telemetry agent runs on the instances, listening on TCP port 9090. The Solutions Architect configures the ALB target group's health check settings to use TCP port 9090. The security group of the EC2 instances is configured to allow inbound TCP traffic on port 8443 from the ALB's security group. All outbound traffic from the instances is allowed. Despite the instances functioning correctly, the ALB marks all targets as unhealthy, and the ASG is repeatedly terminating and replacing the instances. Which action should the Solutions Architect take to resolve this issue?

Update the EC2 instances' security group to allow inbound TCP traffic on port 9090 from the ALB's security group.

Change the target group's health check configuration to use the 'traffic port' setting, since Application Load Balancers can only perform health checks on the port where application traffic is received.

Add an outbound rule to the EC2 instances' security group allowing TCP traffic on port 9090 to the ALB's security group, as security groups are stateless and require explicit egress rules.

Create an Amazon Route 53 latency routing policy targeting the EC2 instances' public IP addresses on port 9090 to handle health checks and bypass the Application Load Balancer's target group health checks.

Cevabı ve açıklamayı göster

Cevap: Update the EC2 instances' security group to allow inbound TCP traffic on port 9090 from the ALB's security group.

Cevap

Update the EC2 instances' security group to allow inbound TCP traffic on port 9090 from the ALB's security group.

The correct option is to update the security group of the EC2 instances to allow inbound TCP traffic on port 9090 from the Application Load Balancer's security group. Since the load balancer is configured to perform health checks on port 9090, but the instances only allow traffic on port 8443, the health check requests are blocked at the instance level. Allowing inbound traffic on port 9090 resolves the issue, and because security groups are stateful, the return traffic is automatically permitted.

Adım Adım Çözüm

Analyze the communication flow for ALB health checks.

The Application Load Balancer originates health check probes targeting TCP port 9090 on the EC2 instances.

The target group has been explicitly configured to perform health checks on TCP port 9090 instead of the standard application port.

Examine the security group configuration of the EC2 instances.

The security group only allows inbound traffic on port 8443 from the ALB security group, thereby blocking the health check probes on port 9090.

To resolve the unhealthy target state, the security group must permit inbound traffic on port 9090 from the ALB.

Evaluate the statefulness of security groups.

No outbound security group rule modification is needed because security groups are stateful and allow return traffic automatically.

Modifying only the inbound rule is sufficient and maintains the principle of least privilege.

Anahtar Kavram

ELB health checks can target a custom port, which must be explicitly allowed by the EC2 instance's security group.

Tahmini Süre:2m 0s

Soru 317Soru →

A SaaS payroll company hosts its platform in the us-east-1 Region. The architecture consists of Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB), and an Amazon RDS for PostgreSQL database. The company needs to design a disaster recovery (DR) plan in the us-west-2 Region. The solution must support a Recovery Time Objective (RTO) of $15$ minutes and a Recovery Point Objective (RPO) of $5$ minutes while minimizing running infrastructure costs in the secondary Region during normal operations.

Which combination of actions should the solutions architect implement to meet these requirements? (Select TWO.)

Geçerli olan tümünü seçin

Create an Amazon RDS cross-region read replica in the secondary Region, and promote it to a standalone DB instance during a failover event.

Create an Auto Scaling group in the secondary Region with a desired capacity of 0, and configure it to scale up using a pre-baked Amazon Machine Image (AMI) during a failover event.

Deploy a scaled-down Auto Scaling group with a minimum capacity of 2 small EC2 instances in the secondary Region to constantly run and monitor the database.

Configure an Amazon Route 53 latency-based routing policy to automatically redirect application traffic to the secondary Region during an outage.

Export automated database snapshots to Amazon S3 Glacier Flexible Retrieval in the secondary Region, and restore the database during a failover event.

Cevabı ve açıklamayı göster

Cevap: Create an Amazon RDS cross-region read replica in the secondary Region, and promote it to a standalone DB instance during a failover event.; Create an Auto Scaling group in the secondary Region with a desired capacity of 0, and configure it to scale up using a pre-baked Amazon Machine Image (AMI) during a failover event.

Cevap

Create an Amazon RDS cross-region read replica in the secondary Region and promote it during failover, and create an Auto Scaling group in the secondary Region with a desired capacity of 0 that scales up using a pre-baked Amazon Machine Image (AMI) during failover.

To meet the RPO of 5 minutes, data must be continuously replicated to the secondary Region. Amazon RDS cross-region read replicas use asynchronous replication to achieve replication lags of just a few seconds. During a failover, the replica is promoted to primary. To achieve a 15-minute RTO while minimizing running costs, a Pilot Light architecture is used. By deploying an Auto Scaling group in the secondary Region with desired capacity set to 0, no compute instances run or charge during normal operations. Upon failover, the Auto Scaling group desired capacity is increased, spinning up instances from a pre-baked AMI in minutes.

Adım Adım Çözüm

Configure database replication to meet RPO.

An Amazon RDS cross-region read replica is created in us-west-2, replicating data asynchronously with a lag of seconds, satisfying the 5-minute RPO.

Asynchronous cross-region replication is required because snapshot copies would take too long and fail the RPO target.

Configure secondary compute resources for cost optimization.

An Auto Scaling group is set up in us-west-2 with desired capacity set to 0.

Setting the capacity to 0 prevents any running compute costs while idle, aligning with the Pilot Light disaster recovery strategy.

Define the failover orchestration steps.

In a failover event, promote the RDS read replica to a primary instance, update the Auto Scaling group capacity to launch instances from the pre-baked AMI, and update DNS records.

This process takes less than 15 minutes, successfully meeting the RTO target.

Anahtar Kavram

Implementing a cost-effective Pilot Light disaster recovery strategy using cross-region database replication and on-demand compute provisioning.

Tahmini Süre:2m 30s

Soru 318Soru →

A company has a web application that receives financial transaction requests from clients. The application must decouple the request reception from the backend processing systems. The transaction volume is highly unpredictable, with sudden spikes throughout the day. It is critical that all transaction requests are processed in the exact order they are received to prevent account balance errors. Which solution meets these requirements while guaranteeing transaction ordering?

Implement an Amazon SQS FIFO queue to buffer incoming transaction requests and process them in order.

Implement an Amazon SQS Standard queue to buffer incoming transaction requests and process them in order.

Write incoming transaction requests directly to an Amazon DynamoDB table configured in provisioned capacity mode to store and process them in order.

Store incoming transaction requests in an Amazon S3 Standard-IA bucket, and delete the objects immediately after processing.

Cevabı ve açıklamayı göster

Cevap: Implement an Amazon SQS FIFO queue to buffer incoming transaction requests and process them in order.

Cevap

Implement an Amazon SQS FIFO queue to buffer incoming transaction requests and process them in order.

The solution that implements an Amazon SQS FIFO queue is correct because SQS FIFO queues are designed to guarantee that messages are processed in the exact order they are received, while also providing decoupling to handle sudden spikes in traffic without losing messages.

Adım Adım Çözüm

Analyze the requirements for decoupling, handling unpredictable traffic spikes, and strict ordering.

The solution must decouple the front-end application from the backend, scale to absorb spikes, and process messages in a strict first-in, first-out sequence.

Decoupling ensures the application remains responsive during spikes, while ordering is necessary to prevent balance calculation errors.

Compare the message ordering capabilities of Amazon SQS queue types.

Amazon SQS Standard queues do not guarantee order. Amazon SQS FIFO queues guarantee strict ordering and exactly-once processing.

This identifies the correct messaging technology that meets the strict chronological processing requirement.

Anahtar Kavram

Decoupling with Amazon SQS FIFO queues to guarantee message ordering and handle unpredictable workloads.

Soru 319Soru →

A digital publishing company hosts a web application in the us-east-1 Region. The application uses an Amazon RDS for MySQL database to store article metadata. The company wants to implement a disaster recovery (DR) strategy in the us-west-2 Region. The solution must achieve a Recovery Point Objective (RPO) of $15$ minutes and a Recovery Time Objective (RTO) of $2$ hours while minimizing ongoing infrastructure costs.

Which strategy should a solutions architect recommend to meet these requirements?

Export daily database backups to Amazon S3, copy the backups to an Amazon S3 Glacier Flexible Retrieval vault in the secondary Region, and restore the database from Glacier during a failover event.

Configure Amazon RDS Multi-AZ replication across both Regions. Use Amazon Route 53 with a latency routing policy to route traffic to active application servers running in both Regions.

Replicate the database to the secondary Region. Keep application servers in the secondary Region turned off, or deploy them using AWS CloudFormation templates only during a failover event.

Replicate the database to the secondary Region. Keep a scaled-down, active fleet of application instances running in the secondary Region to scale up immediately during a failover event.

Cevabı ve açıklamayı göster

Cevap: Replicate the database to the secondary Region. Keep application servers in the secondary Region turned off, or deploy them using AWS CloudFormation templates only during a failover event.

Cevap

Replicate the database to the secondary Region. Keep application servers in the secondary Region turned off, or deploy them using AWS CloudFormation templates only during a failover event.

The correct strategy is a Pilot Light approach. Replicating the database to the secondary Region ensures the data is ready and meets the 15-minute RPO. Keeping application servers shut down or deploying them on demand using templates minimizes ongoing infrastructure costs while comfortably meeting the 2-hour RTO.

Adım Adım Çözüm

Identify the target constraints

RPO is

15

minutes, RTO is

2

hours, and ongoing infrastructure costs must be minimized.

The solution must satisfy all constraints, especially the balance between speed of recovery (RTO/RPO) and cost.

Evaluate database replication options

Database must be actively replicated to the secondary Region (e.g., using cross-region read replicas) to meet the

15

-minute RPO.

Traditional daily backups do not meet a

15

-minute RPO constraint.

Evaluate compute scaling options

Since the RTO is

2

hours, application servers do not need to be running continuously. They can be created on-demand or kept turned off.

Keeping compute resources powered down or provisioning them on-demand via templates (Pilot Light) minimizes ongoing costs while easily fitting into the

2

-hour window.

Anahtar Kavram

Disaster Recovery (DR) Strategies (Pilot Light vs. Warm Standby)

Tahmini Süre:1m 0s

Soru 320Soru →

A gaming company runs a matchmaking service on Amazon EC2 instances within an Auto Scaling group (ASG). The instances are located in a private subnet and registered with an Application Load Balancer (ALB) target group. The matchmaking service is configured to listen on TCP port 7000. The target group is configured to route traffic to port 7000. Currently, all EC2 instances are marked as unhealthy by the ALB.

The security group for the ALB allows inbound HTTPS traffic from 0.0.0.0/0 and all outbound traffic. The security group for the EC2 instances allows inbound TCP traffic on port 7000 from the ALB's security group. The Network ACL (NACL) for the private subnet has been configured to allow inbound traffic on port 7000 and outbound traffic on port 7000.

Which two changes should the solutions architect make to resolve this issue and allow the instances to register as healthy? (Select two.)

Geçerli olan tümünü seçin

Modify the target group's health check settings to query port 7000 rather than the default port.

Update the outbound rules of the private subnet's network access control list (NACL) to allow TCP traffic to ephemeral ports (1024-65535).

Add an outbound rule to the EC2 instances' security group allowing TCP traffic to the Application Load Balancer's security group on port 7000 to permit response packets.

Configure the target group health check protocol to use HTTPS on the default port to secure the transmission of health check probes.

Set up an Amazon Route 53 Latency routing policy pointing to the Application Load Balancer to dynamically route health check traffic away from the private subnet.

Cevabı ve açıklamayı göster

Cevap: Modify the target group's health check settings to query port 7000 rather than the default port.; Update the outbound rules of the private subnet's network access control list (NACL) to allow TCP traffic to ephemeral ports (1024-65535).

Cevap

The solutions architect should modify the target group's health check settings to query port 7000 rather than the default port, and update the outbound rules of the private subnet's network access control list (NACL) to allow TCP traffic to ephemeral ports (1024-65535).

The correct options modify the target group health check port to query the custom service port (port 7000) and open the outbound network ACL to allow return traffic on ephemeral ports (1024-65535). Since target groups default to port 80 for health checks, the mismatch must be corrected. Additionally, because network ACLs are stateless, return packets from port 7000 to the load balancer's ephemeral ports must be permitted explicitly.

Adım Adım Çözüm

Analyze the target group health check behavior.

By default, an Elastic Load Balancing target group performs health checks using the HTTP protocol on the default port (port 80). Since the EC2 instances are hosting the matchmaking service on port 7000 and their security group only allows inbound traffic on port 7000, any checks to port 80 will fail.

Correcting the target group health check port configuration is necessary to ensure the load balancer probes the active port of the application.

Evaluate the network access control list (NACL) configuration.

Network ACLs are stateless. While the inbound NACL allows incoming connections to port 7000, the outbound NACL restricts response traffic to only port 7000. When the Application Load Balancer initiates a connection, it uses an ephemeral source port (1024-65535). The EC2 instances attempt to send response packets to this ephemeral port, but the outbound NACL blocks them.

Allowing outbound TCP traffic to ephemeral ports (1024-65535) is required in the private subnet's NACL to permit successful return communications.

Anahtar Kavram

Auto Scaling and Elastic Load Balancing target group health check configuration, and security group/network ACL interactions.

Tahmini Süre:2m 0s

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