SAA-C03 Design Resilient Architectures Practice Test 23 — 15 Questions

Question 1

A company runs a critical API on Amazon EC2 behind an Application Load Balancer in a single AWS Region. The business requires the API to keep serving traffic if an entire Availability Zone becomes unavailable, and the recovery must not depend on any manual step. The database is Amazon RDS for PostgreSQL configured as a Single-AZ instance. Which combination of changes should a solutions architect implement to meet these requirements?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Configure the Auto Scaling group to span at least two Availability Zones with a health check grace period, and convert the RDS instance to a Multi-AZ DB instance deployment.. Automatic recovery across an Availability Zone failure needs redundant compute and a database that fails over on its own. A multi-AZ Auto Scaling group keeps the API serving through the load balancer, and Multi-AZ RDS maintains a synchronous standby that is promoted automatically to the same endpoint, so no human action is required.

Answer

Enable Multi-AZ on the Application Load Balancer by adding a second listener in a different Availability Zone.

Answer

Take hourly RDS snapshots and configure an Auto Scaling lifecycle hook to restore the snapshot into a new Availability Zone during a failure.

Answer

Create an RDS read replica in a second Availability Zone and update the application to write to the replica when the primary fails.

Question 2

A logistics company runs an order processing system on Amazon EC2 instances that read and write to an Amazon RDS for MySQL database. The database is currently a Single-AZ deployment. The company needs the database to survive an Availability Zone failure with automatic failover and minimal downtime. The application connects using a hardcoded DNS name. Which change should a solutions architect make?

Accepted Answer

Convert the RDS for MySQL database to a Multi-AZ DB instance deployment and continue using the existing endpoint.. Converting the RDS for MySQL database to a Multi-AZ DB instance deployment creates a synchronous standby in a second Availability Zone and enables automatic failover. The database endpoint remains unchanged, so the application's hardcoded DNS name continues to work, satisfying the requirements for zone resilience and minimal downtime.

Answer

Enable automated backups with a longer retention period and restore the database to a new instance during a failure.

Answer

Create a read replica in another Availability Zone and update the application to use the read replica endpoint for writes.

Answer

Migrate the database to Amazon DynamoDB with global tables enabled.

Question 3

A startup runs a stateless image-resizing API on a fleet of EC2 instances behind an Application Load Balancer. The instances store uploaded source images on their own instance store volumes before processing. During a routine scale-in event, an instance was terminated and several in-flight uploads were lost. The architect must make the design resilient to instance loss without changing the API code. What should the architect do?

Accepted Answer

Store uploaded images in Amazon S3 and have instances read from and write to the bucket instead of local disk. The root cause is that uploaded images live on instance store volumes, which are ephemeral and destroyed when an instance terminates. Relocating the source images to Amazon S3 removes the dependency on any single instance and gives the fleet shared, durable storage, so scale-in no longer causes loss. The remaining options delay or observe termination or reduce its frequency, but none preserve the data itself.

Answer

Increase the Auto Scaling group's minimum capacity so that instances are rarely terminated

Answer

Enable detailed CloudWatch monitoring and create an alarm that notifies operators before scale-in occurs

Answer

Configure an EC2 Auto Scaling lifecycle hook to delay instance termination until uploads complete

Question 4

A healthcare provider hosts a patient-records API on Amazon EC2 instances in a single Availability Zone behind an Application Load Balancer. An audit finds the architecture cannot tolerate the loss of that Availability Zone. Budget is limited, and the API reads from an Amazon Aurora MySQL cluster that currently has one writer instance and no replicas. Which change most effectively addresses the audit finding?

Accepted Answer

Add an Aurora Replica in a second Availability Zone and register EC2 instances in that same second Availability Zone with the load balancer's target group.. The audit finding is about surviving the loss of one Availability Zone, so the fix must add capacity in a second zone for both tiers. An Aurora Replica in another zone gives the database an automatic failover target, and EC2 instances in that same zone let the load balancer continue serving requests. Cross-Region designs exceed the requirement and the budget.

Answer

Enable Aurora backtrack on the cluster and increase the EC2 Auto Scaling group maximum size within the existing Availability Zone.

Answer

Convert the cluster to Aurora Global Database and add a secondary AWS Region for the EC2 fleet.

Answer

Replace Aurora with a single-instance Amazon RDS for MySQL deployment and place all EC2 instances in an Auto Scaling group with a desired capacity of one.

Question 5

A startup runs a stateless web tier on Amazon EC2 instances in an Auto Scaling group that spans three Availability Zones. The team wants the application to keep serving requests even if one instance becomes unresponsive, without operator involvement. What should the solutions architect configure?

Accepted Answer

An Application Load Balancer with health checks that route traffic only to healthy targets.. Health-checked load balancing is the mechanism that detects an unresponsive instance and removes it from the traffic path automatically. Because the tier is stateless and already spans three Availability Zones, the Application Load Balancer can shift requests to remaining healthy instances while the Auto Scaling group replaces the failed one.

Answer

A Network Load Balancer configured with a single target group and no health checks.

Answer

An Elastic IP address associated with each EC2 instance in the Auto Scaling group.

Answer

An Auto Scaling group with a scheduled scaling policy that adds instances every morning.

Question 6

A solutions architect is designing a highly available relational database tier for a customer-facing order system that must survive the loss of an entire Availability Zone with minimal administrative effort and no application connection-string changes during failover. (Choose two.)

Accepted Answer

Enable a Multi-AZ DB cluster deployment for the RDS database so a writer and two readable standbys span three Availability Zones. Both Multi-AZ deployment types keep a synchronous standby copy of the data in another Availability Zone and expose a stable endpoint that survives automatic failover, which removes the need to edit connection strings. A Multi-AZ DB cluster goes further by adding two readable standbys across three zones and offering faster failover. The remaining choices rely on asynchronous replicas, manual promotion, or snapshot restores that all require operator action.

Answer

Create manual read replicas in each Availability Zone and repoint the application to a replica after failover

Answer

Store the database on an EC2 instance with an EBS volume and take nightly snapshots to a second Availability Zone

Answer

Rely on the RDS automated backup retention window to restore the instance into a different Availability Zone during an outage

Question 7

A logistics company runs an order-processing workload that reads messages from an Amazon SQS queue and writes results to an Amazon DynamoDB table. Occasionally the same order is processed twice and produces duplicate shipments. The architects must ensure each order is processed exactly once end to end, while keeping throughput as high as possible. What should they do?

Accepted Answer

Use an SQS FIFO queue with a message group ID per order and a DynamoDB conditional write on the order ID.. Exactly-once processing requires both a transport that deduplicates and orders messages per key, and an idempotent write at the destination. An SQS FIFO queue with per-order message group IDs provides the first, and a DynamoDB conditional write on the order ID provides the second, so retries cannot create duplicate shipments.

Answer

Keep the SQS Standard queue and increase the visibility timeout to several hours.

Answer

Enable DynamoDB Streams on the table and process changes with a second Lambda function.

Answer

Move the queue to Amazon SNS and subscribe a Lambda function to fan out the orders.

Question 8

A startup runs a nightly batch job on a single EC2 instance that reads a large dataset from Amazon S3, performs transformations, and writes results back to S3. The job takes about two hours, and the team wants the job to restart automatically if the instance fails or is terminated by AWS. The job is idempotent and can safely resume from the beginning. What is the MOST operationally efficient way to meet this requirement?

Accepted Answer

Place the instance in an Auto Scaling group with a minimum and desired capacity of one, use a launch template that installs and starts the job at boot, and configure a lifecycle hook to keep the instance in service until the job completes.. A single-instance Auto Scaling group is the managed way to keep exactly one healthy instance running and to replace it automatically when it is terminated or fails. Supplying the job through a launch template's user data means every replacement instance starts the job again, and because the job is idempotent, restarting from the beginning is acceptable. No custom alarm or recovery scripting is required.

Answer

Use EC2 Auto Recovery to recover the instance onto new hardware and attach an Amazon EBS volume that persists the job's progress.

Answer

Create an Amazon CloudWatch alarm on the StatusCheckFailed metric that invokes an AWS Lambda function to call the EC2 RebootInstances API.

Answer

Convert the job into an AWS Lambda function with a 15-minute timeout and trigger it on a nightly Amazon EventBridge schedule.

Question 9

A healthcare analytics platform processes streaming records with an AWS Lambda function that writes results to an Amazon DynamoDB table. The pipeline must not lose records if the function throws an error, and the operations team wants to inspect and reprocess failed records without writing custom retry code. Which approach should the solutions architect use?

Accepted Answer

Configure the event source mapping with a maximum retry count and a destination on failure set to an Amazon SQS queue configured as a dead-letter queue. Lambda event source mappings support a maximum retry count plus an on-failure destination that captures the failed batch after retries are exhausted. Pointing that destination at an SQS queue gives the team a durable holding area where failed records can be examined and replayed, satisfying both no-loss and no-custom-code goals. The other options either only tune performance, rely on nonexistent indefinite retries, or reintroduce the custom logic the team wants to eliminate.

Answer

Write a wrapper inside the function that catches exceptions and re-sends the batch to the stream before returning success

Answer

Set the function's timeout to the maximum value and rely on Lambda's built-in retry of the entire batch until it succeeds

Answer

Increase the Lambda function's reserved concurrency so that retries happen faster and failures are less likely

Question 10

A healthcare analytics team runs a containerized reporting service on Amazon ECS with the Fargate launch type in a single Availability Zone. The service must remain available if one Availability Zone fails, and it must scale automatically based on CPU utilization. The tasks are stateless and write output to Amazon S3. Which configuration should a solutions architect implement?

Accepted Answer

Create an ECS service with a task count of two, place the tasks in subnets in two Availability Zones, register them with a target group behind an Application Load Balancer, and attach a target-tracking scaling policy based on ECSServiceAverageCPUUtilization.. Resilience against an Availability Zone failure requires task capacity in more than one zone, and an Application Load Balancer with health checks directs traffic only to healthy tasks. Because the tasks are stateless and store output in S3, no shared state must be replicated. Application Auto Scaling with a target-tracking policy on ECSServiceAverageCPUUtilization then adjusts task count to match demand without manual intervention.

Answer

Configure the ECS service with two tasks in the same subnet of one Availability Zone and add a Network Load Balancer with cross-zone load balancing enabled.

Answer

Use the EC2 launch type with an Auto Scaling group spanning two Availability Zones and a scheduled scaling policy that adds instances at peak hours.

Answer

Deploy the ECS service with a task count of one and enable deployment circuit breaker with rollback so that a failed task is automatically replaced.

Question 11

A financial services firm runs a stateful trading application on EC2 instances in an Auto Scaling group. Each instance maintains an in-memory cache that takes several minutes to rebuild after a restart, and the team wants the application to survive the loss of an Availability Zone with minimal disruption. The application cannot be made stateless in the near term. Which approach should a solutions architect recommend?

Accepted Answer

Configure the Auto Scaling group to span three Availability Zones with a capacity that leaves headroom in each zone, and enable instance warm-up and health check grace periods so that replacement instances are fully initialized before receiving traffic.. For a stateful application that cannot be re-architected immediately, the practical resilience pattern is to run warmed instances in more than two Availability Zones so that a single zone loss leaves sufficient capacity already serving traffic. Warm-up and grace period settings are essential because they stop the Auto Scaling group from killing instances that are still rebuilding their in-memory caches, which would otherwise produce repeated restarts and prolonged unavailability.

Answer

Move the in-memory cache to an Amazon ElastiCache for Redis cluster with Multi-AZ enabled and keep the Auto Scaling group in one Availability Zone.

Answer

Create a second Auto Scaling group in another Availability Zone and use Amazon Route 53 failover routing with health checks to switch traffic when the primary zone fails.

Answer

Enable EC2 Auto Recovery on all instances and configure the Auto Scaling group to use a single Availability Zone with a larger instance type.

Question 12

A media company stores master video files in an Amazon S3 bucket in the us-east-1 Region. A compliance policy requires that the data remain readable even if the entire us-east-1 Region becomes unavailable, and the recovery point objective is 15 minutes. The team wants the lowest operational overhead and does not want to modify application code. Which solution should the architect implement?

Accepted Answer

Enable S3 Cross-Region Replication to a bucket in us-west-2 with S3 Replication Time Control set to 15 minutes and enable versioning on both buckets.. Cross-Region Replication with S3 Replication Time Control replicates new and updated objects to a second Region within a defined 15-minute window and supports versioning and metadata. The destination bucket can serve reads during a Regional outage without application changes, giving the required RPO with minimal operational effort.

Answer

Use AWS DataSync to copy the bucket to a second Region every hour and store the copy in an S3 bucket with versioning enabled.

Answer

Configure an S3 Lifecycle policy to transition objects to S3 Glacier Deep Archive in a second Region and restore them during a disaster.

Answer

Enable S3 Transfer Acceleration on the bucket and use an Amazon CloudFront distribution with origin failover to serve the video files.

Question 13

A small e-commerce company runs a web application on a single Amazon EC2 instance in one Availability Zone. The instance stores session state locally and the database runs on the same instance. The company wants the application to survive an Availability Zone failure with minimal changes and no data loss for committed orders. Which combination of changes should the architect recommend?

Accepted Answer

Move the database to Amazon RDS with a Multi-AZ deployment, place the web tier in an Auto Scaling group across multiple Availability Zones, and store session state in Amazon ElastiCache for Redis.. RDS Multi-AZ keeps a synchronous standby in a second Availability Zone and fails over automatically, protecting committed orders. An Auto Scaling group across AZs maintains the web tier, and externalizing sessions to ElastiCache for Redis removes dependence on a single instance, so the application survives an AZ failure with minimal redesign.

Answer

Create an Amazon Machine Image of the instance and configure a weekly cron job to launch a replacement instance in a second Availability Zone if the first fails.

Answer

Attach an additional Amazon EBS volume to the instance and take hourly snapshots to Amazon S3 for disaster recovery.

Answer

Enable detailed monitoring on the EC2 instance and create an Amazon CloudWatch alarm that reboots the instance when the status check fails.

Question 14

A financial services firm runs a critical API on Amazon EC2 instances behind a Network Load Balancer. The API must handle a sudden loss of one Availability Zone and continue serving traffic with no manual failover. The instances are in an Auto Scaling group that currently uses a single subnet in one Availability Zone. Which change should the architect make?

Accepted Answer

Recreate the Auto Scaling group with subnets in at least two Availability Zones, enable the Network Load Balancer across those subnets, and attach a target group with health checks.. The Network Load Balancer must be enabled in subnets across multiple Availability Zones, and the Auto Scaling group must launch instances in those same subnets. With health checks on the target group, failed instances and the failed AZ are removed from rotation automatically, so the API remains available without manual failover.

Answer

Replace the Network Load Balancer with an Application Load Balancer and enable sticky sessions with a long cookie duration.

Answer

Create an Amazon Route 53 latency-based routing record that points to the Network Load Balancer and set a failover routing policy with a health check.

Answer

Enable cross-zone load balancing on the Network Load Balancer and increase the Auto Scaling group desired capacity to four instances in the existing subnet.

Question 15

A healthcare company runs a critical patient-records API on Amazon EC2 instances behind an Application Load Balancer in a single AWS Region. The compliance team mandates that the API remain available even if an entire AWS Region becomes unavailable. The company wants a cost-effective solution that avoids running full production capacity in a second Region at all times. Which approach BEST meets these requirements?

Accepted Answer

Deploy the API in a second Region with a minimal warm standby environment, and use Amazon Route 53 failover routing with health checks to shift traffic when the primary Region fails.. A warm standby in a second Region with Route 53 failover routing provides cross-Region resilience while controlling cost. The standby runs at reduced capacity and can be scaled up during a Regional failure. Health checks trigger automatic DNS failover, so clients reach the surviving Region without manual intervention. This design directly addresses the need to survive a full Region outage without duplicating full production capacity at all times.

Answer

Create an Amazon CloudFront distribution with the existing ALB as the origin, and enable origin failover to a second ALB in another Region.

Answer

Take regular Amazon EBS snapshots of the EC2 instances and copy them to a second Region, then restore the instances manually if the primary Region fails.

Answer

Enable Multi-AZ deployment for the EC2 instances and the Application Load Balancer, and rely on the existing single-Region architecture to survive a Regional failure.