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CCNA Reliability and Business Continuity Questions

35 questions · Reliability and Business Continuity · All types, answers revealed

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1
MCQmedium

A company runs a stateful web application on a single Amazon EC2 instance. The application stores session state in memory and writes critical data to an Amazon EBS volume. The SysOps administrator needs to implement a highly available architecture that can tolerate an Availability Zone (AZ) failure. The administrator plans to use an Auto Scaling group and an Application Load Balancer (ALB). Which combination of steps is required to make the application highly available while preserving session and data durability across AZ failures?

A.Create an AMI of the current instance, configure an Auto Scaling group with a launch template that uses the AMI, and attach the existing EBS volume to new instances.
B.Create a multi-AZ Auto Scaling group and use sticky sessions (session affinity) on the ALB to tie users to specific instances.
C.Use an Auto Scaling group across multiple AZs, migrate session storage to Amazon ElastiCache (multi-AZ), and migrate application data from EBS to Amazon EFS (file system mounted across AZs).
D.Use an Auto Scaling group in a single AZ and use a Multi-AZ RDS instance for data storage.
AnswerC

ElastiCache provides a shared, cross-AZ in-memory session store. EFS provides a shared, cross-AZ file system. The Auto Scaling group launches instances in multiple AZs, and the ALB distributes traffic. This architecture survives an AZ failure.

Why this answer

It addresses both session state and data durability across AZ failures. Migrating session storage to ElastiCache (multi-AZ) ensures session data survives instance failure, and migrating application data from EBS to EFS provides a shared, multi-AZ file system that persists independently of any single EC2 instance. This combination allows the Auto Scaling group to launch new instances in any AZ and immediately access both session and application data.

Exam trap

The trap here is that candidates often assume sticky sessions (session affinity) alone are sufficient for high availability, but they fail to realize that sticky sessions do not replicate session state across instances, so an instance failure still loses the session data.

How to eliminate wrong answers

Option A is wrong because attaching the existing EBS volume to new instances is not possible across AZs (EBS volumes are AZ-scoped) and does not provide a shared, durable data layer; it also fails to address session state persistence. Option B is wrong because sticky sessions alone do not preserve session data if the instance fails; they only route traffic to the same instance, and if that instance goes down, the session is lost. Option D is wrong because using a single AZ for the Auto Scaling group cannot tolerate an AZ failure, and while Multi-AZ RDS handles database durability, it does not address the application's in-memory session state or EBS-stored data.

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2
MCQmedium

A company runs a critical production database on Amazon RDS for MySQL with Multi-AZ deployment. The SysOps administrator needs to be automatically notified when a failover event occurs, and also capture the exact time and reason for the failover for compliance purposes. Which AWS service or feature should be used to capture the failover event details with the least operational overhead?

A.Create an Amazon CloudWatch Events rule that matches the 'RDS DB Instance Event' for 'failover' and sends the event to an Amazon SNS topic for notification and logging.
B.Enable detailed monitoring on the RDS instance and stream the logs to Amazon CloudWatch Logs where a metric filter can detect failover patterns.
C.Configure AWS CloudTrail to log all RDS API calls and analyze the logs for the 'Failover' event type.
D.Use AWS Config to create a config rule that evaluates whether the 'DBInstanceStatus' changes to 'failover' and then trigger a remediation action.
AnswerA

Amazon CloudWatch Events (now part of Amazon EventBridge) natively integrates with RDS event notifications, emitting a structured event whenever a DB instance experiences a failover. By creating a rule that matches the 'RDS DB Instance Event' source and the specific detail type for failover, you can route that event to an SNS topic in near-real time, enabling automated alerting, logging, and downstream remediation. This is the intended, low-overhead approach because RDS already publishes these lifecycle events, and no polling or custom detection logic is required.

Why this answer

Amazon CloudWatch Events (now part of Amazon EventBridge) can match RDS DB Instance events, including 'failover', and route them to an SNS topic for notification and to CloudWatch Logs for logging. This approach requires no custom scripting or polling, providing the least operational overhead while capturing the exact time and reason for the failover directly from the RDS event stream.

Exam trap

The trap here is that candidates confuse CloudTrail (which logs API calls) with RDS events (which log internal service events), leading them to choose CloudTrail even though automatic failovers are not API-driven and thus not recorded by CloudTrail.

How to eliminate wrong answers

Option B is wrong because detailed monitoring on RDS provides enhanced metrics (e.g., CPU, memory) but does not generate failover events or detect failover patterns; metric filters on CloudWatch Logs would require RDS to log failover details to CloudWatch Logs, which RDS does not do by default. Option C is wrong because AWS CloudTrail logs API calls (e.g., FailoverDBInstance), not internal failover events triggered by AWS; a Multi-AZ failover is an automatic process, not an API call, so CloudTrail will not capture it. Option D is wrong because AWS Config evaluates resource configuration changes (e.g., DBInstanceStatus) but does not natively detect a 'failover' status change; the DBInstanceStatus transitions through multiple states (e.g., 'creating', 'available', 'resetting-master-credentials') and 'failover' is not a valid status—Config rules would require custom logic and still not capture the exact reason for the failover.

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3
Multi-Selecteasy

Which TWO actions should a SysOps administrator take to ensure high availability of a web application running on EC2 instances? (Choose two.)

Select 2 answers
A.Enable termination protection on all EC2 instances.
B.Launch all EC2 instances in a single Availability Zone.
C.Use a larger instance type for all EC2 instances.
D.Configure an Auto Scaling group with a health check to replace unhealthy instances.
E.Deploy EC2 instances across multiple Availability Zones.
AnswersD, E

Auto Scaling automatically replaces unhealthy instances.

Why this answer

An Auto Scaling group with a health check can automatically detect and replace unhealthy EC2 instances, ensuring that the web application remains available even if an instance fails. The health check can be configured to use Elastic Load Balancing (ELB) health checks or EC2 status checks to determine instance health, and the Auto Scaling group will launch a new instance to replace any that fails the health check.

Exam trap

The trap here is that candidates often confuse termination protection (a safety feature) with high availability, or think that larger instance types inherently provide fault tolerance, when in fact only redundancy across multiple Availability Zones and automated health-based replacement ensure high availability.

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4
MCQmedium

A company runs a critical web application on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The application uses session stickiness (sticky sessions) to maintain user sessions. The SysOps administrator notices that when instances are replaced during a scale-in or failure event, users lose their session data. The administrator needs to preserve session data across instance failures without losing stickiness benefits. What should the administrator do?

A.Disable sticky sessions on the ALB and configure the application to store session data in an external session store like Amazon ElastiCache for Redis.
B.Increase the stickiness duration to a very high value so that sessions are not lost during brief interruptions.
C.Change the Auto Scaling group to use a larger instance type to handle more sessions per instance, reducing the likelihood of session loss.
D.Configure the Auto Scaling group to use a larger minimum size and a lower maximum, so instances are less likely to be terminated.
AnswerA

Disabling sticky sessions and moving session state to an external service like ElastiCache for Redis decouples user session data from individual EC2 instance lifecycles. When an ALB routes requests to any healthy instance, the instance can retrieve the session from Redis, so a failed or terminated instance does not lose state. Because ElastiCache replicates across AZs, sessions also survive single-cache-node failures, making the app tier effectively stateless and highly resilient.

Why this answer

It eliminates the dependency on stickiness by storing session data externally in Amazon ElastiCache for Redis. This way, if an instance fails or is scaled in, any other instance can retrieve the session data from the shared cache, preserving the user session. Disabling sticky sessions is necessary because with external storage, stickiness is no longer needed and can cause uneven load distribution.

Exam trap

The trap is that candidates may think they need to keep stickiness active, but the correct solution is to remove stickiness and store session data externally. Stickiness only provides routing affinity, not data persistence, and with external storage, any instance can serve any session.

How to eliminate wrong answers

Option B is wrong because increasing the stickiness duration does not preserve session data when an instance is terminated or fails; it only controls how long the ALB remembers the routing cookie, but the session data stored locally on the instance is still lost. Option C is wrong because using a larger instance type does not solve the fundamental problem of session data being stored locally; it only reduces the frequency of scale-in events but does not protect against instance failures or replacements. Option D is wrong because adjusting the Auto Scaling group's minimum and maximum sizes does not prevent session loss during scale-in or failure events; it only changes the number of instances running, but any instance that is terminated or replaced will still lose its locally stored session data.

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5
MCQmedium

A company runs a stateful web application on a single Amazon EC2 instance. The SysOps administrator needs to implement a high availability architecture that can tolerate an Availability Zone (AZ) failure. The application stores session state in memory and also writes critical data to an Amazon EBS volume. The administrator wants to use an Auto Scaling group and an Application Load Balancer (ALB). Which combination of steps is required to make the application highly available?

A.Create an Auto Scaling group that spans at least two Availability Zones, attach the existing EBS volume to the new instances, and use an ALB to distribute traffic.
B.Migrate session state to Amazon ElastiCache for Redis, store critical data in Amazon EFS, create an Auto Scaling group across multiple AZs, and place it behind an ALB.
C.Place the EC2 instance in an Auto Scaling group with a minimum and maximum of 1 in the same AZ, and attach an Elastic IP to the instance.
D.Use an ALB with the existing single instance as the target, and enable cross-zone load balancing.
AnswerB

This option makes the application stateless at the compute layer by externalizing session state to ElastiCache for Redis, which all instances can access, and storing critical application data on Amazon EFS, a shared regional file system. An Auto Scaling group spanning multiple Availability Zones ensures that an instance failure or entire AZ outage triggers replacement, while the ALB distributes traffic only to healthy instances and performs health checks. This architecture achieves both high availability and horizontal scalability because no unique state is tied to any individual EC2 instance.

Why this answer

It addresses both the stateless requirement for horizontal scaling and the persistence of critical data across AZ failures. Migrating session state to ElastiCache for Redis removes the dependency on local instance memory, allowing any instance to handle any request. Storing critical data on Amazon EFS provides a shared, NFS-based file system that is accessible from all instances across multiple AZs, unlike EBS which is tied to a single AZ.

Combining these with a multi-AZ Auto Scaling group and an ALB ensures the application can survive an entire AZ outage.

Exam trap

The trap here is that candidates assume EBS volumes can be shared across instances or AZs, or that a single-instance setup with an ALB provides high availability, when in fact EBS is a single-AZ resource and the ALB requires multiple healthy targets to tolerate failures.

How to eliminate wrong answers

Option A is wrong because EBS volumes are AZ-scoped and cannot be attached to instances in a different AZ; attaching the existing EBS volume to new instances in another AZ is impossible without snapshotting and recreating, which defeats high availability. Option C is wrong because keeping a single instance in one AZ with an Elastic IP does not provide fault tolerance for an AZ failure; the Auto Scaling group with min/max of 1 cannot replace the instance in a different AZ automatically, and the Elastic IP does not reroute traffic to a healthy instance. Option D is wrong because using an ALB with a single instance as the target and enabling cross-zone load balancing does not add redundancy; if the instance or its AZ fails, the ALB has no other targets to route traffic to, so the application becomes unavailable.

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6
MCQhard

A company runs a critical web application on Amazon EC2 instances that are part of an Auto Scaling group. The application receives unpredictable traffic spikes. The SysOps administrator needs to ensure that when a scale-out event occurs, new instances are ready to serve traffic quickly to minimize latency spikes. Currently, the instance launch and configuration process (including software installs and cache warming) takes about 5 minutes. The administrator wants to reduce the time it takes for new instances to start serving traffic. Which combination of Auto Scaling features should be used?

A.Use a launch template that includes a pre-warmed Amazon Machine Image (AMI) with all software pre-installed, and configure the Auto Scaling group to use a larger instance type to reduce initialization time.
B.Implement an Auto Scaling warm pool with a minimum number of pre-initialized instances in a 'Stopped' state. Configure the scaling policy to move instances from the warm pool to the Auto Scaling group when needed.
C.Use scheduled scaling to predictively launch instances before the traffic spikes based on historical patterns.
D.Configure lifecycle hooks to add a wait time during instance launch so that the instance is fully configured before it is placed behind the load balancer.
AnswerB

A warm pool maintains instances that have been fully launched and configured but are stopped or in a standby state. When scale-out occurs, instances from the warm pool are started or moved into service quickly, drastically reducing the time to handle traffic.

Why this answer

An Auto Scaling warm pool maintains a pool of pre-initialized instances in a 'Stopped' state that are fully configured (software installed, cache warmed) and ready to serve traffic. When a scale-out event occurs, instances from the warm pool are moved to the Auto Scaling group and transitioned to 'Running' state, bypassing the 5-minute launch and configuration delay, thereby minimizing latency spikes.

Exam trap

The trap here is that candidates often confuse warm pools with lifecycle hooks or pre-warmed AMIs, assuming that reducing software install time alone is sufficient, when the real bottleneck is the entire instance initialization process that warm pools bypass.

How to eliminate wrong answers

Option A is wrong because using a pre-warmed AMI reduces software installation time but does not eliminate the instance launch and initialization overhead (e.g., kernel boot, network setup, cache warming), and using a larger instance type does not inherently reduce initialization time—it may even increase it due to more hardware resources to initialize. Option C is wrong because scheduled scaling relies on predictable traffic patterns and cannot handle unpredictable traffic spikes; it would either over-provision or under-provision for unexpected demand. Option D is wrong because lifecycle hooks add a wait time during instance launch, which would increase the time before the instance is ready to serve traffic, contradicting the goal of reducing latency spikes.

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7
MCQhard

A company runs a critical database workload on an Amazon RDS for MySQL DB instance with Multi-AZ deployment in the us-east-1 region. The SysOps administrator must design a disaster recovery strategy that can recover from a complete regional outage. The Recovery Time Objective (RTO) is 2 hours and the Recovery Point Objective (RPO) is 1 hour. Which solution meets these requirements at the lowest cost?

A.Create manual snapshots of the DB instance every hour and copy them to another AWS Region.
B.Enable automated backups with a retention period of 35 days and restore to a different Region when needed.
C.Create a cross-Region read replica in another Region and promote it to a standalone DB instance during a disaster.
D.Use AWS Database Migration Service (DMS) to continuously replicate data to a DB instance in another Region.
AnswerC

A cross-Region read replica provides continuous asynchronous replication with low lag (typically seconds). In a disaster, promoting the replica to a primary instance takes only minutes, meeting the RTO and RPO requirements with minimal cost.

Why this answer

A cross-Region read replica continuously replicates data from the primary RDS MySQL instance to another Region with minimal lag, typically achieving an RPO of seconds to minutes, well within the 1-hour requirement. Promoting the replica to a standalone instance during a disaster can be done in minutes, meeting the 2-hour RTO. This approach is the lowest cost among the viable options as it uses existing replication infrastructure without additional data transfer fees for snapshots or DMS replication instances.

Exam trap

The trap here is that candidates often choose Option B (automated backups) because they assume backups can be restored cross-Region, but automated backups are Region-specific and do not support cross-Region restore without additional snapshot copy configuration, which is not mentioned in the option.

How to eliminate wrong answers

Option A is wrong because manual snapshots taken every hour would incur significant storage costs for storing and copying snapshots across Regions, and the copy process can take longer than 1 hour, potentially exceeding the RPO. Option B is wrong because automated backups with a 35-day retention period are stored only in the source Region and cannot be restored to a different Region; cross-Region snapshot copy must be explicitly configured and is not part of automated backups. Option D is wrong because AWS DMS incurs additional costs for a replication instance and data transfer, making it more expensive than a cross-Region read replica, and it adds operational complexity for continuous replication that is unnecessary when native MySQL replication can achieve the same RPO/RTO.

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8
Multi-Selectmedium

A SysOps administrator is troubleshooting an issue where an Application Load Balancer (ALB) is returning 503 errors to clients. The target group has healthy EC2 instances. Which THREE possible causes should the administrator investigate? (Choose three.)

Select 3 answers
A.The load balancer is not attached to a subnet.
B.The security group for the load balancer is blocking traffic.
C.The load balancer has reached its capacity limit.
D.The target group has no registered targets.
E.The target group health check is misconfigured.
AnswersA, B, C

Incorrect because the load balancer must be attached to subnets to function; if not, it would fail to provision, but the ALB is already running and returning 503, so this is not a likely cause.

Why this answer

If the load balancer is not attached to a subnet, it cannot route traffic to targets and may return 503 errors. Option B is correct because the load balancer's security group must allow inbound traffic from clients; if it blocks HTTP/HTTPS traffic, the ALB cannot forward requests and returns 503 errors. Option C is correct because an ALB has a capacity limit; once reached, it cannot handle new requests and returns 503 errors.

Option D is incorrect because the stem explicitly states the target group has healthy EC2 instances, meaning registered targets exist. Option E is incorrect because the health check is functioning correctly since targets are healthy; a misconfigured health check would cause targets to be unhealthy, contradicting the given information.

Exam trap

The trap is that candidates often assume a 503 error always indicates unhealthy targets, but the question explicitly states healthy instances, so they must consider other causes like security group misconfiguration, ALB capacity limits, or the load balancer not being attached to a subnet.

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9
Multi-Selecthard

A company wants to implement a disaster recovery solution for its on-premises database using AWS. The solution must have an RPO of less than 1 hour and an RTO of less than 4 hours. Which THREE steps should the SysOps administrator take? (Choose THREE.)

Select 3 answers
A.Set up a cross-Region read replica for the RDS instance.
B.Launch an EC2 instance with the database software and configure replication.
C.Use AWS Database Migration Service (DMS) to replicate data to an RDS instance.
D.Use AWS DataSync to sync the database files to Amazon S3.
E.Configure the RDS instance with Multi-AZ.
AnswersA, B, C

A cross-Region read replica creates a continuously updated, asynchronous replicate of an RDS database in a different AWS Region, with typical replication lag well under the 1-hour RPO. Promoting the replica makes it a standalone writable instance, a process that generally completes within minutes and satisfies the RTO. This is a solid DR approach, but it presupposes that the database is already running on RDS; for an on-premises source, you would need an initial migration into RDS before this option becomes viable.

Why this answer

A cross-Region read replica for an RDS instance provides asynchronous replication to a secondary Region. After promoting the replica, the RTO can be under 4 hours, and the RPO is typically less than 1 hour. Option B is correct by launching an EC2 instance with the same database software and configuring continuous replication (e.g., log shipping or mirroring) from the on-premises database.

This allows failover to the EC2 instance within the RPO and RTO targets. Option C is correct as AWS DMS can perform ongoing replication from the on-premises database to an RDS instance, meeting the RPO requirement with minimal data loss. Together, these steps form a multi-layered DR strategy: DMS for continuous replication, EC2 as a standby, and a cross-Region replica for regional resilience.

Exam trap

Candidates often assume Multi-AZ (Option E) is a valid DR solution. However, Multi-AZ only provides high availability within a single Region, with synchronous replication and automatic failover. It does not protect against Region-wide outages or on-premises failures, and does not meet the cross-Region disaster recovery requirement implied by the need for an RPO < 1 hour and RTO < 4 hours for an on-premises database.

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10
MCQhard

A company runs a critical database on an RDS for PostgreSQL instance in a single Availability Zone. The database experiences high write latency. The SysOps Administrator needs to improve the database's reliability and performance without downtime. Which solution meets these requirements?

A.Modify the RDS instance to be Multi-AZ with a standby in another Availability Zone.
B.Create a Multi-AZ deployment in the same Availability Zone.
C.Increase the allocated storage for the RDS instance.
D.Create a read replica in another Availability Zone and redirect read traffic.
AnswerA

Modifying the RDS instance to a Multi-AZ deployment provisions a synchronous standby replica in a different Availability Zone, and Amazon RDS automatically fails over to that standby if an AZ outage or primary instance failure occurs. This change can typically be applied without downtime, as it only requires a metadata modification and provisioning of the standby. This gives the database the high availability and automatic failover that the company needs.

Why this answer

Enabling Multi-AZ for an RDS for PostgreSQL instance provisions a standby replica in a different Availability Zone and synchronously replicates data to it. This eliminates the single point of failure, improving reliability. The modification is performed as a zero-downtime operation via a DNS update, meeting the requirement for no downtime.

Note that Multi-AZ improves availability but does not reduce write latency; performance improvement may come from offloading backups and other administrative tasks to the standby.

Exam trap

The trap here is that candidates confuse Multi-AZ (synchronous replication for high availability) with read replicas (asynchronous replication for read scaling), assuming a read replica can improve write performance or reliability when it only helps with read traffic.

How to eliminate wrong answers

Option B is wrong because Multi-AZ requires the standby to be in a different Availability Zone; deploying in the same AZ provides no fault isolation and does not improve reliability. Option C is wrong because increasing allocated storage addresses capacity or IOPS limits but does not improve reliability through redundancy or reduce write latency caused by synchronous replication overhead. Option D is wrong because a read replica is asynchronous and does not improve write latency or reliability for the primary database; it only offloads read traffic, leaving the primary as a single point of failure.

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11
Multi-Selectmedium

Which TWO steps should a SysOps administrator take to ensure that an RDS for MySQL instance can withstand an Availability Zone failure? (Choose 2)

Select 1 answer
A.Enable Multi-AZ deployment.
B.Create a read replica in a different AZ.
C.Enable automated backups with a short retention period.
D.Enable deletion protection on the DB instance.
E.Enable provisioned IOPS for the DB instance.
AnswersA

Enable Multi-AZ deployment. This provisions a synchronous standby replica in a different AZ and provides automatic failover, ensuring the instance can withstand an AZ failure.

Why this answer

To withstand an Availability Zone failure, the RDS instance must provide automatic failover to a standby in a different AZ. Only Multi-AZ deployment (Option A) achieves this by provisioning a synchronous standby replica and enabling automatic failover. Automated backups (Option C) are for point-in-time recovery, not high availability, so they do not help during an ongoing AZ failure.

Exam trap

The trap here is that candidates often confuse read replicas with Multi-AZ deployments, assuming a read replica in a different AZ provides automatic failover, when in fact read replicas are asynchronous and require manual promotion, making them unsuitable for automatic AZ failure recovery.

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12
MCQeasy

A company stores critical data in an S3 bucket. The SysOps administrator needs to ensure that the data is durable and can be recovered if an entire AWS Region becomes unavailable. What is the MOST cost-effective solution?

A.Use AWS Backup to manually copy the bucket to another Region.
B.Enable S3 Versioning on the bucket.
C.Use S3 Standard storage class.
D.Configure S3 Cross-Region Replication to a bucket in another Region.
AnswerD

CRR replicates data to another Region for disaster recovery.

Why this answer

D is correct because S3 Cross-Region Replication (CRR) automatically replicates objects to a bucket in another AWS Region, ensuring data durability and recoverability even if an entire Region becomes unavailable. This is the most cost-effective solution for cross-region disaster recovery as it only incurs replication costs and storage fees in the destination Region, without requiring manual intervention or additional infrastructure.

Exam trap

The trap here is that candidates often confuse S3 Versioning (which protects against accidental deletion within a Region) with Cross-Region Replication (which protects against Regional outages), leading them to select Option B as a cheaper alternative without understanding that versioning does not provide geographic redundancy.

How to eliminate wrong answers

Option A is wrong because AWS Backup does not support manual copying of S3 buckets to another Region; it automates backup policies but does not provide a direct 'copy bucket' feature, and manual copying would be inefficient and error-prone. Option B is wrong because enabling S3 Versioning protects against accidental deletion or overwrite within the same Region but does not protect against a Regional outage, as all versions remain in the same Region. Option C is wrong because using the S3 Standard storage class provides high durability (99.999999999%) within a single Region but does not replicate data across Regions, so it cannot recover data if the entire Region becomes unavailable.

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13
MCQmedium

A company runs a web application on Amazon EC2 instances in an Auto Scaling group that spans two Availability Zones. The application uses an Application Load Balancer (ALB) that is deployed across the same Availability Zones. The SysOps administrator wants to ensure the application remains available if an entire Availability Zone fails. Which configuration is essential for this high availability?

A.Configure the Auto Scaling group with at least one instance in each Availability Zone.
B.Enable cross-zone load balancing on the Application Load Balancer.
C.Use an Amazon Route 53 health check to route traffic away from a failed AZ.
D.Attach an Elastic IP address to each instance in the Auto Scaling group to ensure IP persistence.
AnswerA

Configuring the Auto Scaling group to maintain at least one instance in each Availability Zone (AZ) ensures that if an entire AZ becomes unavailable, the remaining AZs still have healthy instances to serve traffic. Auto Scaling also performs AZ rebalancing, which automatically detects when one AZ has fewer instances and launches replacements in that AZ to maintain a balanced distribution. This is the fundamental mechanism for achieving fault tolerance at the AZ level within a single region, which is exactly what the requirement demands.

Why this answer

For high availability across an Availability Zone (AZ) failure, the Auto Scaling group must have at least one healthy instance in each AZ. This ensures that if one AZ becomes unavailable, the ALB can route traffic to instances in the remaining AZ. Without this minimum distribution, a single AZ failure could leave the application with zero healthy targets if all instances were in the failed AZ.

Exam trap

The trap here is that candidates often confuse cross-zone load balancing (which balances traffic) with instance distribution across AZs (which ensures survival), leading them to select Option B instead of recognizing that without instances in each AZ, no load balancing can save the application.

How to eliminate wrong answers

Option B is wrong because cross-zone load balancing distributes traffic evenly across all registered instances in all AZs, but it does not protect against an entire AZ failure—it only balances load, not ensures instance survival. Option C is wrong because Route 53 health checks can route traffic away from a failed AZ at the DNS level, but they do not guarantee that instances exist in the surviving AZ; the Auto Scaling group must already have instances there. Option D is wrong because Elastic IP addresses are not used with Auto Scaling groups (which use dynamic scaling and replacement) and do not provide high availability; they are static IPs for individual instances, not for AZ failure resilience.

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14
MCQmedium

A company runs a global e-commerce application that uses Amazon DynamoDB as its primary database. The application requires single-digit millisecond read and write latency from any region and must continue to operate during a regional outage with minimal data loss. Which DynamoDB feature should the SysOps administrator enable to meet these requirements?

A.DynamoDB Accelerator (DAX)
B.DynamoDB global tables
C.DynamoDB Point-in-Time Recovery (PITR)
D.DynamoDB Auto Scaling
AnswerB

DynamoDB global tables automatically replicate each item write to all selected AWS Regions, creating active-active replica tables with multi-region read and write capability. This cross-region replication gives users low-latency access because they can be served by a nearby replica, and it provides business continuity by allowing another Region to continue serving traffic during a Regional outage without manual data restore. Because every replica holds a full copy of the data, a Region failure is effectively transparent at the table level, assuming your application can reroute traffic.

Why this answer

DynamoDB global tables provide multi-Region, multi-active replication, enabling single-digit millisecond reads and writes from any Region while offering automatic failover and recovery during a regional outage. This feature uses DynamoDB Streams to replicate data across Regions with eventual consistency, meeting the requirement for continued operation with minimal data loss.

Exam trap

The trap here is that candidates often confuse DynamoDB Accelerator (DAX) with global tables, assuming a caching layer can provide multi-Region availability, but DAX is Region-specific and does not replicate data across Regions.

How to eliminate wrong answers

Option A is wrong because DynamoDB Accelerator (DAX) is an in-memory cache that reduces read latency but does not provide multi-Region replication or write availability during a regional outage. Option C is wrong because Point-in-Time Recovery (PITR) enables backup restoration to any point within the last 35 days but does not provide real-time failover or cross-Region read/write capability. Option D is wrong because Auto Scaling adjusts provisioned throughput based on traffic but does not replicate data across Regions or ensure availability during a regional outage.

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15
MCQeasy

A production RDS MySQL database stores financial records. The team needs the ability to restore the database to any point within the last 7 days in case of accidental data deletion. Automated backups are currently disabled. What must be configured?

A.Enable automated backups and set the backup retention period to 7 days
B.Create a manual DB snapshot every night using the AWS CLI on a schedule
C.Enable Multi-AZ to maintain a synchronous standby replica in a second Availability Zone
D.Enable RDS read replicas and promote one if data deletion occurs
AnswerA

Automated backups with a 7-day retention period keep daily snapshots and transaction logs for 7 days. Any point within the retention window is recoverable. Transaction logs allow recovery to any 5-minute interval within that window. Setting the period to 0 disables automated backups and PITR entirely.

Why this answer

To restore an RDS MySQL database to any point within the last 7 days, you must enable automated backups and set the backup retention period to 7 days. Automated backups enable point-in-time recovery (PITR), which allows restoration to any second within the retention window using binary logs. Without automated backups, RDS cannot perform PITR, even if manual snapshots exist.

Exam trap

The trap here is that candidates often confuse manual snapshots with automated backups, not realizing that only automated backups enable point-in-time recovery, while manual snapshots are static and cannot be used for granular restoration.

How to eliminate wrong answers

Option B is wrong because manual DB snapshots capture only a single point in time and do not provide the continuous binary log data needed for point-in-time recovery to any arbitrary moment within 7 days. Option C is wrong because Multi-AZ provides high availability and automatic failover, but it does not create backups or enable point-in-time recovery; it only maintains a synchronous standby replica. Option D is wrong because RDS read replicas are designed for read scaling and, while they can be promoted to a standalone instance, they do not provide point-in-time recovery capabilities and rely on the same backup configuration as the source instance.

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16
MCQeasy

Refer to the exhibit. An IAM policy is attached to an IAM user. Which action can the user perform?

A.Start an EC2 instance.
B.Describe EC2 instances.
C.Stop an EC2 instance.
D.Terminate an EC2 instance.
AnswerC

StopInstances is explicitly allowed and not denied.

Why this answer

The IAM policy grants the ec2:StopInstances action, which allows the user to stop EC2 instances. The condition restricts the action to instances with a specific tag, but the core permission is for stopping instances, making option C correct.

Exam trap

The trap here is that candidates may confuse the ec2:StopInstances action with ec2:TerminateInstances, as both involve changing instance state, but only StopInstances is granted in the policy.

How to eliminate wrong answers

Option A is wrong because the policy does not include ec2:RunInstances, which is required to start a new EC2 instance. Option B is wrong because the policy does not include ec2:DescribeInstances, which is needed to list or describe EC2 instances. Option D is wrong because the policy does not include ec2:TerminateInstances, which is required to terminate an EC2 instance.

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17
MCQmedium

A company uses AWS CloudFormation to deploy its infrastructure. The SysOps administrator needs to ensure that the application stack can be recreated in another AWS Region in the event of a disaster. The stack includes an RDS MySQL database and an EC2 instance running a web server. The administrator wants to automate the backup of the RDS database and the EC2 instance configuration. What is the MOST efficient way to achieve this?

A.Use S3 to store database dump files and instance configuration scripts.
B.Create manual snapshots of the RDS database and EC2 instance every day and copy them to the secondary region.
C.Store the CloudFormation template in S3 and use it to recreate the stack in the secondary region.
D.Use AWS Backup to create backup plans that include the RDS instance and EC2 instance, and copy backups to the secondary region.
AnswerD

AWS Backup provides a fully managed, policy-based backup solution that can target both RDS instances and EC2 instances (via Amazon Machine Images) within a single backup plan. You can schedule automated backups, apply retention and lifecycle policies, and configure cross-region replication to the secondary region, ensuring consistent disaster recovery without custom scripting or manual snapshots. This is the most efficient and reliable approach because it centralizes backup management and automates the entire DR copy process.

Why this answer

AWS Backup provides a centralized, automated backup service that can back up RDS databases (with automated backups) and EC2 instances (via AMIs). It supports cross-region copy, making it ideal for disaster recovery. Option A is wrong because storing database dump files and scripts in S3 is not a fully automated or integrated solution; it requires custom scripting and does not capture incremental changes efficiently.

Option B is wrong because manual snapshots require manual intervention and are not automated. Option C is wrong because the CloudFormation template only captures infrastructure configuration, not the database data or EC2 instance state.

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18
Multi-Selectmedium

A company is designing a backup strategy for its on-premises file servers to AWS. Which TWO services can be used to back up data to AWS? (Choose TWO.)

Select 2 answers
A.AWS Backup
B.AWS Snowball
C.AWS Storage Gateway (File Gateway)
D.Amazon EFS
E.S3 Transfer Acceleration
AnswersA, C

AWS Backup is the correct answer because it natively supports backing up on-premises workloads via the AWS Backup Gateway, which connects your on-premises virtual machines to AWS Backup. This service allows you to define backup policies, retention rules, and lifecycle management in a single place, covering both cloud and on-premises resources. Unlike simple data replication or file syncing tools, AWS Backup provides a centralized, scheduled, and auditable backup solution that ensures recoverability of on-premises VMs.

Why this answer

AWS Backup is correct because it provides a fully managed, policy-based backup service that can centrally automate and manage backups for on-premises file servers via the AWS Backup Gateway (formerly Storage Gateway Virtual Tape Library). It integrates with AWS Storage Gateway to back up on-premises data to S3 and Glacier, supporting file-level recovery without needing custom scripts.

Exam trap

The trap here is that candidates confuse data transport services (Snowball) or storage targets (EFS) with backup services, or mistake a performance feature (S3 Transfer Acceleration) for a backup solution, when the question specifically asks for services that can be used to back up data to AWS.

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19
MCQhard

A company runs a critical stateful web application on Amazon EC2 instances in a single AWS region. The application stores user session data in an Amazon ElastiCache for Redis cluster. The SysOps administrator must design a disaster recovery (DR) strategy that can survive a complete regional outage with a Recovery Point Objective (RPO) of 15 minutes and a Recovery Time Objective (RTO) of 1 hour. The application must be able to redirect users to the DR region with minimal manual effort. Which combination of actions meets these requirements?

A.Use Amazon Route 53 with weighted routing to distribute traffic between the two regions. Use a global DynamoDB table for session data, and launch EC2 instances in the DR region only when a failure is detected using AWS CloudFormation StackSets.
B.Create a read replica of the ElastiCache Redis cluster in the DR region using the native cross-region replication feature. Use Route 53 with failover routing to point to the DR region ALB when the primary health check fails. Pre-configure EC2 instances in an Auto Scaling group in the DR region.
C.Use an Amazon CloudFront distribution with multiple origins (primary and DR). Enable session stickiness at the CloudFront level. Use EC2 instances in both regions behind separate ALBs. No special data replication is needed because sessions are stored in Redis.
D.Use EC2 instances with an Auto Scaling group in both regions. Schedule a Lambda function to take snapshots of the Redis cluster every 15 minutes and copy them to the DR region. Use Route 53 latency routing to direct users to the nearest region.
AnswerB

Global Datastore for Redis provides cross-Region replication with low RPO. Pre-configured Auto Scaling groups in the DR region ensure that compute capacity is ready. Route 53 failover routing automatically redirects traffic when the primary ALB health check fails. This combination meets the RPO and RTO requirements with minimal manual effort.

Why this answer

ElastiCache for Redis supports cross-region replication via a read replica in the DR region, which can keep session data synchronized with minimal lag, meeting the 15-minute RPO. Route 53 failover routing with health checks on the primary region's ALB automatically redirects traffic to the pre-configured DR region EC2 instances and ALB, achieving the 1-hour RTO with minimal manual effort. Pre-configuring the DR region with an Auto Scaling group ensures compute capacity is ready, while the read replica provides the required data availability.

Exam trap

The trap here is that candidates may assume snapshot-based replication (Option D) is sufficient for a 15-minute RPO, but they overlook the inherent latency and potential data loss from periodic snapshots, and that latency routing (Option D) does not provide health-based failover, while weighted routing (Option A) lacks automatic failover capability.

How to eliminate wrong answers

Option A is wrong because weighted routing does not automatically fail over during a regional outage; it distributes traffic based on weights, not health, and using a global DynamoDB table for session data is unnecessary since the application uses ElastiCache for Redis, not DynamoDB. Option C is wrong because CloudFront does not natively support session stickiness based on ElastiCache session data, and without cross-region replication of Redis, the DR region would have no session data, violating the RPO. Option D is wrong because scheduling snapshots every 15 minutes and copying them to the DR region cannot guarantee an RPO of 15 minutes due to snapshot timing and transfer delays, and latency routing does not provide automatic failover during a regional outage; it routes based on latency, not health.

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20
MCQmedium

A company runs a stateless web application on Amazon EC2 instances in an Auto Scaling group across two Availability Zones. The SysOps administrator needs to ensure that the application can tolerate a failure of an entire Availability Zone. Which configuration is required?

A.Use an Application Load Balancer (ALB) that spans both Availability Zones with health checks enabled.
B.Enable termination protection on all Amazon EC2 instances.
C.Place the Amazon EC2 instances in a cluster placement group.
D.Associate an Elastic IP address with the primary instance.
AnswerA

An Application Load Balancer (ALB) is a regional service that spans all Availability Zones (AZs) in its subnet configuration and actively sends health-check requests to each registered target. When an EC2 instance or an entire AZ fails health checks, the ALB automatically stops routing new traffic to that target and continues serving requests from healthy instances in other AZs. Coupled with an Auto Scaling group that spans multiple AZs, this design provides both elasticity and zone-failure tolerance, because the ALB constantly updates its target membership based on instance health and scaling events.

Why this answer

An Application Load Balancer (ALB) that spans both Availability Zones with health checks enabled distributes incoming traffic across EC2 instances in multiple AZs. If an entire AZ fails, the ALB automatically routes traffic only to healthy instances in the remaining AZ, ensuring the stateless web application remains available. Health checks detect instance or AZ failure and remove unhealthy targets from the load balancer's target group, which is essential for fault tolerance.

Exam trap

The trap here is that candidates often confuse high availability with data durability or instance protection, leading them to choose termination protection or Elastic IPs, when the core requirement is automatic traffic rerouting across AZs, which only a load balancer with health checks can provide.

How to eliminate wrong answers

Option B is wrong because termination protection prevents accidental deletion of an instance but does not provide any resilience against an Availability Zone failure; it does not reroute traffic or maintain application availability. Option C is wrong because a cluster placement group is designed for low-latency, high-throughput networking within a single AZ; it actually increases the risk of simultaneous failure if that AZ goes down, as all instances are in the same AZ. Option D is wrong because associating an Elastic IP with the primary instance only provides a static public IP, which does not survive an AZ failure and does not offer automatic failover or load balancing across AZs.

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21
MCQhard

An EC2 instance runs a database on a 2 TB EBS gp3 volume. After a corruption event, the team must restore from a snapshot. When they detach the corrupted volume, attach a new volume restored from the snapshot, and start the database, performance is 10 to 20 times lower than normal for the first two hours. What causes this behavior, and what feature eliminates it?

A.Enable Fast Snapshot Restore (FSR) on the snapshot in the target Availability Zone before creating the replacement volume
B.Use a Provisioned IOPS (io2) volume type instead of gp3 to get higher IOPS during initialization
C.Run a full dd or fio pre-warm pass over the volume after attaching it but before starting the database
D.Increase the EBS volume size to 4 TB when restoring from the snapshot to get double the throughput baseline
AnswerA

FSR fully initializes the volume's block index immediately upon creation. The first I/O to any block is served from EBS at full throughput rather than waiting for lazy initialization from S3. For a 2 TB database volume where I/O latency determines restore time, FSR eliminates the 2-hour performance degradation period entirely.

Why this answer

When you create an EBS volume from a snapshot, the volume's data blocks are lazily loaded from Amazon S3 on first access. This causes high latency and low IOPS until all blocks are fetched. Fast Snapshot Restore (FSR) pre-initializes the volume in a specific Availability Zone, eliminating the need for lazy loading and providing full performance immediately.

Exam trap

The trap here is that candidates assume performance issues are due to volume type (gp3 vs io2) or size, rather than recognizing the fundamental lazy-load initialization behavior of EBS snapshots and the specific feature (FSR) designed to mitigate it.

How to eliminate wrong answers

Option B is wrong because Provisioned IOPS (io2) volumes do not eliminate the lazy-load initialization penalty; they only provide consistent IOPS after the volume is fully initialized, but the initial access still suffers from the same on-demand fetch from S3. Option C is wrong because running dd or fio pre-warms the volume manually, but this is a workaround, not a feature that eliminates the behavior, and it still requires the same time-consuming initialization process. Option D is wrong because increasing the volume size to 4 TB does not change the lazy-load behavior; it only increases the baseline throughput for the volume after initialization, but the initial performance degradation remains until all blocks are loaded.

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22
Multi-Selectmedium

A company is designing a highly available architecture for a web application. The application uses an Application Load Balancer (ALB) and an Auto Scaling group of EC2 instances. Which TWO steps should the company take to ensure the architecture is resilient to an Availability Zone failure? (Select TWO.)

Select 2 answers
A.Set the Auto Scaling group's desired capacity to a high number.
B.Create a CloudWatch alarm that triggers if the ALB has elevated 5xx errors.
C.Configure the Auto Scaling group to launch instances in at least two Availability Zones.
D.Use a single EC2 instance type for all instances.
E.Configure the ALB to be internet-facing and enable cross-zone load balancing.
AnswersC, E

Distributing instances across AZs ensures availability if one AZ fails.

Why this answer

Launching EC2 instances in at least two Availability Zones (AZs) ensures that if one AZ fails, the Auto Scaling group can continue to serve traffic from instances in the remaining AZ(s). This is a fundamental design pattern for high availability within a single AWS Region, as it distributes the application across physically separate data centers.

Exam trap

The trap here is that candidates often confuse scaling capacity (Option A) or monitoring (Option B) with the architectural requirement of distributing resources across multiple Availability Zones, which is the only way to survive an AZ failure.

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23
MCQhard

A company runs a critical MySQL database on an Amazon RDS DB instance in a single Availability Zone. The SysOps administrator needs to implement a disaster recovery solution with a Recovery Point Objective (RPO) of 5 minutes and a Recovery Time Objective (RTO) of 1 hour, while minimizing costs. Which solution meets these requirements?

A.Enable Multi-AZ deployment with a synchronous standby replica in another Availability Zone
B.Create a cross-Region read replica and promote it to a standalone DB instance during a disaster
C.Enable cross-Region automated backups to another Region
D.Take daily automated snapshots and copy them to another Region manually
AnswerC

Enabling cross-Region automated backups continuously replicates both automated snapshots and transaction logs to a chosen destination Region without running any compute resources there. This service-managed feature provides a typical RPO of about 5 minutes because transaction logs are shipped frequently, and an RTO of under 1 hour by restoring the latest snapshot and rolling forward logs. Since you only pay for storage in the destination Region until you actually perform a restore, this is the most cost-effective and operationally simple way to meet the stated DR requirements.

Why this answer

Cross-Region automated backups replicate transaction logs to another AWS Region with a typical lag of a few minutes, enabling point-in-time recovery (PITR) that can meet an RPO of 5 minutes. When a disaster occurs, you can restore the automated backup to a new DB instance in the destination Region, and the RTO depends on the restore time, which can be under 1 hour for a properly sized instance. This solution minimizes costs by avoiding the continuous compute and storage overhead of a standby replica or read replica.

Exam trap

The trap here is that candidates often confuse cross-Region read replicas (asynchronous, higher RPO) with cross-Region automated backups (log-based, lower RPO), or assume Multi-AZ provides cross-Region disaster recovery when it only covers AZ failures within a single Region.

How to eliminate wrong answers

Option A is wrong because Multi-AZ with a synchronous standby replica only protects against an Availability Zone failure within the same Region, not a cross-Region disaster, and it incurs the cost of a full standby instance. Option B is wrong because a cross-Region read replica is asynchronous and can have replication lag exceeding 5 minutes, making it unable to guarantee an RPO of 5 minutes; additionally, promoting a read replica to a standalone instance can take longer than 1 hour due to the need to stop replication and apply pending changes. Option D is wrong because daily automated snapshots provide an RPO of up to 24 hours, far exceeding the required 5-minute RPO, and manual copying adds operational overhead and delay.

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24
MCQmedium

Regulatory requirements mandate that all RDS and EBS backups are replicated to a secondary AWS region within 24 hours of creation. The company has workloads in us-east-1 and must replicate backups to eu-west-1. Restoring from the secondary region must be possible without manual copying steps during a disaster. What service and configuration implements this requirement?

A.Create an AWS Backup plan with a cross-Region copy rule that replicates recovery points to a backup vault in eu-west-1 within 24 hours
B.Schedule a Lambda function that calls CreateDBSnapshot and CopyDBSnapshot to replicate RDS snapshots, and CreateSnapshot and CopySnapshot for EBS volumes to eu-west-1
C.Enable RDS automated backups with cross-region replication and configure EBS snapshot copy separately using Data Lifecycle Manager
D.Use S3 Cross-Region Replication to replicate the backup bucket containing RDS and EBS snapshots to eu-west-1
AnswerA

AWS Backup's cross-Region copy rule runs automatically after each successful backup job. The copy is encrypted with the destination vault's KMS key. In a disaster, operators restore directly from the eu-west-1 vault — no manual cross-region data transfer is needed. A single backup plan can cover multiple resource types (RDS and EBS), satisfying the consolidated requirement.

Why this answer

AWS Backup is the correct service because it natively supports cross-Region copy rules that automatically replicate recovery points (including RDS snapshots and EBS snapshots) to a backup vault in a secondary Region within a specified time window. This meets the 24-hour replication requirement and enables direct restores from the secondary Region without manual copying, as the backup vault in eu-west-1 contains the replicated recovery points ready for use.

Exam trap

The trap here is that candidates often assume they need to use separate services (like Lambda or DLM) for each resource type, missing that AWS Backup provides a unified, managed solution that handles both RDS and EBS snapshots with cross-Region replication and direct restore capabilities.

How to eliminate wrong answers

Option B is wrong because while a Lambda function could technically replicate snapshots, it requires custom code, error handling, and scheduling, and does not provide the native, managed cross-Region restore capability without manual steps; it also lacks the built-in compliance tracking of AWS Backup. Option C is wrong because RDS automated backups with cross-Region replication only apply to RDS, not EBS volumes, and Data Lifecycle Manager (DLM) for EBS snapshots does not support cross-Region copy natively; DLM only copies within the same Region, so EBS snapshots would not be replicated to eu-west-1. Option D is wrong because S3 Cross-Region Replication replicates objects in an S3 bucket, but RDS and EBS snapshots are not stored as S3 objects by default; they are stored in AWS-managed snapshot storage, and even if you manually copy snapshots to S3, the replication would not create usable snapshots in the secondary Region for direct restore.

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25
MCQmedium

A company runs a web application on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The application stores session state in memory on each instance. The SysOps administrator wants to make the application highly available across multiple Availability Zones without losing session data when instances are terminated or replaced. The solution must minimize application changes. Which approach should the administrator take?

A.Use sticky sessions (session affinity) on the ALB and configure the Auto Scaling group with a larger min size.
B.Store session data in a shared Amazon ElastiCache cluster and modify the application to read/write session state to ElastiCache.
C.Deploy the application in multiple AWS Regions and use Amazon Route 53 with latency-based routing.
D.Store session data in an Amazon RDS for MySQL database and configure the application to read/write session state to the database.
AnswerB

ElastiCache provides a centralized, in-memory data store (such as Redis) that can be shared by all EC2 instances in the Auto Scaling group. By moving session state to ElastiCache, the application becomes stateless at the instance level, so any instance can serve any user request without losing session data. ElastiCache supports replication and automatic failover, making session data highly available across Availability Zones. This directly satisfies the HA requirement and is the best practice for a decoupled web tier.

Why this answer

Storing session state in a shared Amazon ElastiCache cluster decouples session data from individual EC2 instances, allowing any instance in the Auto Scaling group to serve any user request without losing session data when instances are terminated or replaced. This approach requires minimal application changes (only modifying the session handler to point to ElastiCache) and supports high availability across multiple Availability Zones by using a replicated ElastiCache cluster (e.g., Redis with replication).

Exam trap

The trap here is that candidates often choose sticky sessions (Option A) because they seem to solve session affinity without code changes, but they fail to realize that sticky sessions do not persist session data across instance terminations, which is the core requirement for high availability without data loss.

How to eliminate wrong answers

Option A is wrong because sticky sessions (session affinity) bind a user's session to a specific EC2 instance; if that instance is terminated or replaced, the session data stored in memory is lost, violating the requirement to not lose session data. Option C is wrong because deploying across multiple AWS Regions with Route 53 latency-based routing does not address session state persistence within a single region; it introduces cross-region latency and complexity without solving the fundamental issue of in-memory session loss on instance termination. Option D is wrong because while storing session data in Amazon RDS for MySQL would persist session state, it introduces significant overhead (e.g., database connection management, schema design, and slower read/write compared to in-memory caching) and requires more extensive application changes than using ElastiCache, which is purpose-built for session storage.

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26
MCQeasy

A company wants to ensure that its Amazon RDS database can withstand the loss of an entire Availability Zone. Which feature should the SysOps administrator enable?

A.Enable automated backups with a retention period of 35 days.
B.Enable Multi-AZ deployment.
C.Take manual snapshots and copy them to another Region.
D.Create a read replica in a different Availability Zone.
AnswerB

Multi-AZ provides automatic failover to a standby in another AZ.

Why this answer

Multi-AZ deployment for Amazon RDS automatically provisions and maintains a synchronous standby replica in a different Availability Zone. If the primary AZ fails, Amazon RDS automatically fails over to the standby, ensuring database availability without manual intervention. This is the only option that directly protects against an entire AZ loss by maintaining a hot standby in a separate AZ.

Exam trap

The trap here is that candidates often confuse a read replica with a Multi-AZ standby, assuming that a read replica in a different AZ can be promoted for failover, but read replicas are asynchronous and require manual promotion, whereas Multi-AZ provides automatic synchronous failover.

How to eliminate wrong answers

Option A is wrong because automated backups with a retention period of 35 days only provide point-in-time recovery to a specific time, not automatic failover or high availability; they do not protect against AZ loss as they are stored within the same Region but not in a separate AZ for immediate failover. Option C is wrong because manual snapshots copied to another Region provide disaster recovery across Regions, not high availability within a Region; they require manual restoration and do not offer automatic failover if an AZ fails. Option D is wrong because a read replica in a different AZ is an asynchronous copy used for offloading read traffic, not for automatic failover; it does not provide synchronous replication or automatic promotion to primary in case of AZ failure, and promoting it requires manual intervention.

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27
MCQmedium

A company hosts a critical web application on Amazon EC2 instances in a single AWS Region (us-east-1). The SysOps administrator needs to implement a Disaster Recovery (DR) solution using a different AWS Region (us-west-2). The DR plan requires a Recovery Time Objective (RTO) of 1 hour and a Recovery Point Objective (RPO) of 15 minutes. The application uses an Amazon Aurora MySQL DB cluster and static assets stored in an Amazon S3 bucket. Which combination of actions should the administrator take to meet these requirements?

A.Create an Aurora cross-Region read replica in us-west-2. Configure S3 Cross-Region Replication from the source bucket to a destination bucket in us-west-2. During DR, promote the read replica to a primary cluster and update DNS.
B.Take a manual snapshot of the Aurora DB cluster every 15 minutes and copy it to us-west-2. Use S3 batch operations to copy assets to us-west-2 daily.
C.Enable Aurora Multi-AZ in us-east-1 and configure S3 transfer acceleration to us-west-2.
D.Use AWS Database Migration Service (DMS) for continuous replication to a DB instance in us-west-2. Use S3 versioning to keep previous object versions.
AnswerA

A cross-Region read replica provides continuous replication for the database, achieving RPO seconds. Promoting it can be done in minutes, meeting RTO of 1 hour. S3 CRR replicates objects asynchronously, typically within minutes, satisfying the RPO.

Why this answer

Aurora cross-Region read replicas provide asynchronous replication with an RPO typically under 1 second, easily meeting the 15-minute RPO requirement. Promoting the read replica to a primary cluster in us-west-2 can be completed within minutes, satisfying the 1-hour RTO. S3 Cross-Region Replication (CRR) automatically replicates static assets to the destination bucket in us-west-2 with near-real-time latency, ensuring the S3 data is also current within the RPO window.

Exam trap

The trap here is that candidates often confuse Multi-AZ (which provides high availability within a single region) with cross-region disaster recovery, or they assume manual snapshots and DMS are simpler alternatives without considering the RPO/RTO constraints and operational overhead.

How to eliminate wrong answers

Option B is wrong because taking manual snapshots every 15 minutes is operationally impractical and cannot guarantee an RPO of 15 minutes due to snapshot creation and copy latency; also, copying assets daily via S3 batch operations far exceeds the 15-minute RPO. Option C is wrong because Aurora Multi-AZ in us-east-1 only provides high availability within a single region, not cross-region disaster recovery, and S3 Transfer Acceleration only improves upload speed to a single bucket, not replication to another region. Option D is wrong because AWS DMS for continuous replication to a DB instance in us-west-2 introduces additional complexity and potential lag that may not meet the 15-minute RPO as reliably as Aurora native replication; S3 versioning alone does not replicate objects to another region, so it fails to provide cross-region DR for static assets.

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28
Drag & Dropmedium

Drag and drop the steps to set up an Amazon S3 bucket policy to grant cross-account access into the correct order.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4

Why this order

Identify the bucket and account, write the policy with correct principal and actions, save, and test.

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29
MCQmedium

An Auto Scaling group launches new EC2 instances when CPU exceeds 70 percent. The instances take 4 minutes to bootstrap (install software, register with a service discovery system, and warm up caches). Without a hook, the load balancer routes traffic to new instances before they are ready, causing 503 errors. What is the correct solution?

A.Add a lifecycle hook on the autoscaling:EC2_INSTANCE_LAUNCHING transition; signal CompleteLifecycleAction(CONTINUE) when bootstrap finishes
B.Increase the load balancer health check grace period to 10 minutes to give instances time to bootstrap
C.Increase the warm-up time in the Auto Scaling group's instance refresh configuration
D.Use a weighted target group with 0 weight for new instances until they are confirmed healthy
AnswerA

The hook holds the instance in Pending:Wait, outside the target group, until the signal arrives. The load balancer never routes traffic to the instance during its Pending:Wait phase. After the CONTINUE signal, the instance enters InService and the load balancer registers it normally. The heartbeat timeout (default 1 hour, configurable) should exceed the bootstrap time.

Why this answer

Lifecycle hooks allow the Auto Scaling group to pause instance launch until a custom action (e.g., bootstrap completion) is finished. By adding a hook on the autoscaling:EC2_INSTANCE_LAUNCHING transition, the instance is held in a 'pending:wait' state. Once the bootstrap script calls CompleteLifecycleAction with the CONTINUE result, the instance transitions to 'InService' and can then be registered with the load balancer, preventing premature traffic and 503 errors.

Exam trap

The trap here is that candidates often confuse the health check grace period (which only delays health checks, not registration) with lifecycle hooks (which actually control when the instance becomes available to the load balancer).

How to eliminate wrong answers

Option B is wrong because increasing the load balancer health check grace period only delays when the load balancer starts checking health; it does not prevent the load balancer from routing traffic to the instance before it is ready. The instance is still added to the target group immediately, and the grace period only affects health check status, not registration. Option C is wrong because the warm-up time in an instance refresh configuration controls how long new instances are given to become healthy during a rolling update, not the initial launch or bootstrap process for a scaling event triggered by CPU.

Option D is wrong because weighted target groups distribute traffic based on weights; setting 0 weight for new instances would prevent all traffic, but the instances would still be registered and could receive traffic if the weight is later changed manually, and this approach does not automatically signal readiness after bootstrap.

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30
MCQmedium

A company runs a stateful web application on a single Amazon EC2 instance with an Elastic IP address. The SysOps administrator needs to increase availability so that if the instance fails, a new instance can be launched quickly with the same configuration and the same IP address. The administrator also needs to ensure data is not lost. Which solution meets these requirements with the least operational overhead?

A.Use an Application Load Balancer with an Auto Scaling group and a launch configuration that includes the Elastic IP
B.Create an AMI from the instance, store data on an Amazon EFS file system, and use an Auto Scaling group with a lifecycle hook to associate the Elastic IP
C.Create a CloudFormation template that launches a new instance and associates the Elastic IP
D.Place the instance in an Auto Scaling group with a minimum of 1 and a maximum of 1, and set the health check to replace unhealthy instances
AnswerB

The AMI provides a pre-configured launch template. EFS provides durable, shared storage for application data. The Auto Scaling group automatically launches a new instance if the current one fails, and the lifecycle hook script associates the Elastic IP to the new instance, ensuring continuity with the same IP.

Why this answer

It separates the stateful data (stored on Amazon EFS) from the compute instance, ensuring data persistence even if the instance fails. Creating an AMI from the instance captures the configuration, and an Auto Scaling group with a lifecycle hook can associate the Elastic IP to the new instance automatically, providing a quick failover with minimal operational overhead.

Exam trap

The trap here is that candidates often assume an Auto Scaling group alone can handle Elastic IP association, but without a lifecycle hook or custom script, the new instance will not automatically receive the Elastic IP, leading to IP address changes and potential downtime.

How to eliminate wrong answers

Option A is wrong because an Application Load Balancer (ALB) does not support Elastic IP addresses; ALBs use DNS names and are designed for distributing traffic, not for preserving a static IP for a stateful application. Option C is wrong because a CloudFormation template requires manual or automated invocation to launch a new instance and associate the Elastic IP, which introduces additional operational overhead and does not automatically handle instance failure detection and replacement. Option D is wrong because placing the instance in an Auto Scaling group with a minimum and maximum of 1 does not automatically launch a new instance with the same configuration or data; it only replaces the instance if it becomes unhealthy, but without a lifecycle hook to associate the Elastic IP or a mechanism to preserve stateful data, the solution fails to meet the requirements.

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31
MCQmedium

A company runs a production Amazon RDS for PostgreSQL DB instance in a single Availability Zone (AZ). The SysOps administrator needs to improve database availability so that in the event of a database failure or AZ outage, a standby instance is automatically promoted with minimal downtime. Which configuration should the administrator enable?

A.Enable automated backups with a retention period of 35 days.
B.Create a read replica in another Availability Zone.
C.Enable Multi-AZ deployment on the DB instance.
D.Schedule manual snapshots to be taken every hour and restore from the latest snapshot when needed.
AnswerC

Enabling Multi-AZ on an Amazon RDS for PostgreSQL DB instance provisions a synchronous standby replica in a different Availability Zone and automatically maintains a synchronous physical replication stream. In the event of an infrastructure failure, an availability zone outage, or a database patching event, Amazon RDS automatically performs a failover to the standby, typically completing within 60–120 seconds and preserving your data because all commits are synchronous. The DNS endpoint remains unchanged, so application connections are transparently redirected without manual intervention. This configuration meets the requirement for automatic failover and high availability.

Why this answer

Multi-AZ deployment automatically creates and maintains a synchronous standby replica in a different Availability Zone. In the event of a failure or AZ outage, Amazon RDS automatically fails over to the standby, typically within 60–120 seconds, with no manual intervention required. This meets the requirement for automatic promotion with minimal downtime.

Exam trap

The trap here is that candidates confuse read replicas (which are for read scaling and require manual promotion) with Multi-AZ (which provides automatic failover), or they overestimate the speed and automation of backups and snapshots for disaster recovery.

How to eliminate wrong answers

Option A is wrong because automated backups only provide point-in-time recovery (PITR) to restore the database to a specific time, not automatic failover with minimal downtime; restoration is a manual process that can take hours. Option B is wrong because a read replica is designed for read scaling and asynchronous replication, not automatic failover; promoting a read replica requires manual intervention and can result in data loss due to replication lag. Option D is wrong because manual snapshots require scheduling and manual restoration, which involves significant downtime and does not provide automatic failover or minimal disruption.

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32
Drag & Dropmedium

Drag and drop the steps to set up an AWS Site-to-Site VPN connection into the correct order.

Drag steps to the numbered slots on the right, or tap a step then tap a slot.

Steps
Order
1Step 1
2Step 2
3Step 3
4Step 4

Why this order

First create and attach the virtual private gateway, then define the customer gateway, then create the VPN connection, configure the on-premises router, and verify the tunnel.

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33
MCQhard

A company runs a critical application on Amazon EC2 instances across multiple Availability Zones. The application stores state data on a shared Amazon EFS file system. The SysOps administrator needs to ensure that the file system remains available if an entire Availability Zone fails. The file system must also provide low-latency access from all instances. Which configuration meets these requirements?

A.Create an EFS file system with the One Zone storage class and mount it from all instances.
B.Create an EFS file system with the Standard storage class, enable replication to another Region, and use DNS failover.
C.Create an EFS file system with the Standard storage class in the same Region, and mount it from all instances using the regional mount target.
D.Create an EFS file system with the Standard storage class, and enable Multi-AZ deployment.
AnswerC

The Standard storage class automatically replicates file system data redundantly across multiple Availability Zones within the Region, providing built-in resilience against an AZ failure. The regional mount target is a single DNS name that resolves to mount targets in each AZ, so instances in any AZ can mount the same file system with low-latency access. If one AZ becomes unavailable, the DNS/ELF service continues to route instances to healthy mount targets, satisfying the high availability requirement.

Why this answer

The EFS Standard storage class stores data redundantly across multiple Availability Zones (AZs) within a Region, ensuring high availability and durability even if an entire AZ fails. By mounting the file system using the regional mount target (which resolves to the EFS file system's regional DNS name), instances in any AZ can access the file system with low latency, as EFS automatically routes traffic to the most appropriate mount target in the same AZ. This configuration meets both the availability and low-latency requirements without additional replication or failover complexity.

Exam trap

The trap here is that candidates confuse EFS's Standard storage class with RDS's Multi-AZ deployment feature, or incorrectly assume that cross-Region replication is necessary for AZ-level fault tolerance, when in fact EFS's regional storage class already provides Multi-AZ redundancy within a single Region.

How to eliminate wrong answers

Option A is wrong because the One Zone storage class stores data only within a single Availability Zone, so if that AZ fails, the file system becomes unavailable, violating the requirement for continued availability during an AZ failure. Option B is wrong because enabling cross-Region replication does not provide low-latency access from all instances within the same Region; it introduces additional latency for cross-Region data access and requires DNS failover, which is not designed for intra-Region AZ failures and adds unnecessary complexity. Option D is wrong because EFS does not support a 'Multi-AZ deployment' configuration; the term 'Multi-AZ' applies to Amazon RDS, not EFS, and EFS inherently provides Multi-AZ redundancy through the Standard storage class, not through a separate deployment option.

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34
MCQhard

A company runs a production web application on AWS using Auto Scaling groups (ASGs) behind an Application Load Balancer (ALB). The application state is stored in an Amazon RDS for MySQL Multi-AZ DB instance. The application experiences periodic traffic spikes, and the current ASG uses a simple scaling policy based on average CPU utilization. Recently, during a spike, the application became unresponsive for several minutes. The CloudWatch metrics show that the CPU utilization on the RDS instance peaked at 80%, and the DB Connections metric reached the maximum allowed. The read replica lag increased to over 10 seconds during the spike. The web servers are stateless and scale out quickly. The operations team needs to improve the reliability and performance of the application to handle future spikes. Which solution should the team implement?

A.Increase the desired capacity of the ASG and add more read replicas to distribute the database load.
B.Increase the DB instance size to a larger instance class and implement an Amazon ElastiCache cluster to cache frequent database queries.
C.Migrate the database to Amazon DynamoDB with auto scaling and rewrite the application to use a serverless architecture with AWS Lambda.
D.Reduce the maximum connections parameter on the RDS instance to prevent connection exhaustion and modify the application code to reduce the number of database queries.
AnswerB

Scaling the DB instance to a larger class directly increases available vCPU, memory, and the maximum connection limit, giving the primary database the headroom needed to absorb the current CPU spike. Implementing an ElastiCache cluster (for example, Redis or Memcached) in front of the database caches the results of frequent, repetitive queries, so those reads never reach the RDS instance, which lowers CPU usage and frees connections for writes and less frequent queries. Together these actions provide both immediate compute capacity and durable read-path relief, exactly matching the incident's requirements.

Why this answer

Increasing the DB instance size provides more CPU and memory capacity to handle the load, and caching with ElastiCache reduces read load on the database by serving frequent queries from cache. This directly addresses high CPU and connection limits on RDS, and reduces read replica lag. Option A is wrong because increasing ASG size and adding more read replicas may increase database load further due to more connections and replication overhead.

Option C is wrong because switching to DynamoDB and Lambda would require significant application changes and DynamoDB may not be suitable for complex queries. Option D is wrong because reducing MaxConnections on RDS would make the problem worse, and modifying application code to reduce queries is not a quick fix.

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35
MCQmedium

A SysOps administrator creates the above IAM policy for a user. The user reports that they cannot delete an object in the bucket 'my-bucket' even though they are using MFA. What is the likely cause?

A.The resource ARN is missing the bucket-level permission.
B.The condition key aws:MultiFactorAuthPresent is incorrectly spelled.
C.The user is not using MFA when making the API call.
D.The policy does not include s3:DeleteObjectVersion.
AnswerC

The condition likely sets `aws:MultiFactorAuthPresent` to `false` or uses the `Bool` operator to deny access when MFA is absent. Because the user made the API call without an MFA token, the condition evaluates to `false`, triggering the `Deny` statement. This is the explicit reason why the delete request fails, as the policy mandates MFA for all actions by this user.

Why this answer

The policy requires MFA for all s3:DeleteObject actions, as indicated by the condition key aws:MultiFactorAuthPresent set to 'true'. If the user reports they cannot delete an object despite using MFA, the most likely cause is that they are not actually using MFA when making the API call — for example, they may have authenticated with long-term credentials (access key/secret key) without a multi-factor authentication session. The condition key checks the presence of an MFA-authenticated session token, not just whether the user has MFA enabled on their account.

Exam trap

The trap here is that candidates confuse 'having MFA enabled on the user account' with 'using MFA in the API call session' — the condition key aws:MultiFactorAuthPresent checks the latter, not the former.

How to eliminate wrong answers

Option A is wrong because the resource ARN 'arn:aws:s3:::my-bucket/*' correctly specifies object-level permissions for all objects in the bucket, and bucket-level permissions (e.g., s3:ListBucket) are not required for the s3:DeleteObject action. Option B is wrong because the condition key 'aws:MultiFactorAuthPresent' is correctly spelled — it is case-sensitive and matches the official AWS documentation. Option D is wrong because s3:DeleteObjectVersion is a separate action for deleting a specific version of an object, and the policy already includes s3:DeleteObject, which covers deleting the current version of an object (the most common operation).

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