SOA-C02 Reliability and Business Continuity Practice Test 3 — 15 Questions

Question 1

Refer to the exhibit. An IAM policy is attached to a group. A SysOps Administrator in that group tries to terminate an EC2 instance with the tag 'Environment=production'. The action fails. What is the most likely reason?

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

Accepted Answer

The instance does not have the tag 'Environment=production'.. The IAM policy explicitly uses a condition key `ec2:ResourceTag/Environment` with `StringEquals` to restrict the `ec2:TerminateInstances` action to only instances tagged with `Environment=production`. If the instance does not have that exact tag, the condition fails, and the action is denied. The SysOps Administrator is in the group that has this policy attached, so the failure is most likely due to the instance lacking the required tag.

Answer

The condition key 'ec2:ResourceTag/Environment' is invalid.

Answer

The policy does not allow the ec2:TerminateInstances action.

Answer

The condition uses 'StringEquals' instead of 'StringLike'.

Question 2

A company is using AWS CloudFormation to manage infrastructure. They want to ensure that if a stack update fails, the stack automatically rolls back to the last known good state. Which two steps should the company take? (Choose TWO.)

Accepted Answer

Set the 'Rollback on failure' option to 'Yes' in the stack update options.. Option B is correct because CloudFormation's stack update options include a 'Rollback on failure' setting (equivalent to the --rollback-configuration / DisableRollback=false behavior); when set to 'Yes', CloudFormation automatically rolls the stack back to the last known good state if the update fails. Option C is correct because creating a change set lets you preview exactly what changes CloudFormation will make, and executing the reviewed change set applies those changes as a single update that still honors rollback-on-failure, so failures revert to the prior good state. Option A is not correct because a stack policy only denies or allows updates to specified resources; it prevents changes rather than restoring the last known good state after a failed update. Option D is not correct because termination protection only blocks accidental stack deletion, not update failures or rollbacks. Option E is not correct because an SNS topic merely notifies you of failure events; it does not perform the automatic rollback.

Answer

Define a stack policy that prevents updates to critical resources.

Answer

Enable termination protection on the stack.

Answer

Configure an Amazon SNS topic to send notifications when the stack update fails.

Question 3

A company wants to ensure that its Amazon S3 data is resilient to an accidental deletion of an entire bucket. Which two actions should the company take? (Choose TWO.)

Accepted Answer

Configure Cross-Region Replication to replicate objects to a bucket in another AWS Region.. Option A is correct because Cross-Region Replication (CRR) copies objects to a bucket in a different AWS Region, so if an entire bucket is accidentally deleted in the source Region, the replicated copies in the destination bucket remain intact and recoverable. Option D is correct because enabling S3 Versioning keeps all versions of every object, so even if objects are deleted (creating delete markers) or overwritten, prior versions can be restored, protecting against accidental deletion of object data. Option B is incorrect because a lifecycle transition to S3 Glacier only changes the storage class of objects and does not protect against deletion of the bucket or its contents. Option C is incorrect because MFA Delete adds an authentication requirement for permanently deleting versions or changing versioning state, but it does not by itself provide a separate copy of the data and does not protect against deletion of the entire bucket. Option E is incorrect because S3 Transfer Acceleration only speeds up uploads and downloads using AWS edge locations and provides no data-resilience or deletion-protection capability.

Answer

Configure a lifecycle policy to transition objects to S3 Glacier after 30 days.

Answer

Enable MFA Delete on the bucket.

Answer

Enable S3 Transfer Acceleration on the bucket.

Question 4

A company runs a critical application on a fleet of EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The application uses an Amazon RDS MySQL Multi-AZ DB instance for persistent storage. The SysOps administrator recently configured a lifecycle hook on the Auto Scaling group to perform a custom action before instance termination. During a recent scale-in event, the administrator noticed that some requests were still being routed to the terminating instance, causing errors. The ALB's deregistration delay is set to 300 seconds. The lifecycle hook has a default timeout of 3600 seconds. The administrator wants to ensure that the instance completes its custom action and that all in-flight requests are drained before the instance is terminated. The custom action typically takes 120 seconds. What should the administrator do to resolve this issue?

Accepted Answer

Reduce the lifecycle hook timeout to 120 seconds. Keep the deregistration delay at 300 seconds.. Reducing the lifecycle hook timeout to 120 seconds ensures the custom action completes and the instance proceeds to termination promptly. Keeping the ALB deregistration delay at 300 seconds provides sufficient time to drain in-flight requests after deregistration. This prevents the instance from remaining in the terminating:wait state while still receiving traffic, avoiding request errors.

Answer

Change the lifecycle hook to use the 'Replace and terminate' type instead of 'Terminate'.

Answer

Disable the lifecycle hook and rely solely on the ALB's deregistration delay to drain connections.

Answer

Increase the deregistration delay to 600 seconds. Keep the lifecycle hook timeout at 3600 seconds.

Question 5

A company uses Amazon S3 to store sensitive financial documents. The company's compliance team requires that all objects be encrypted at rest using server-side encryption with AWS KMS managed keys (SSE-KMS). Additionally, the compliance team requires that if an object is not accessed for 90 days, it should be automatically moved to Amazon S3 Glacier to reduce costs. The SysOps administrator is tasked with implementing these requirements. The administrator creates an S3 bucket and enables default encryption with SSE-KMS. Then, the administrator creates a lifecycle policy with a transition action to Glacier after 90 days. During testing, the administrator notices that objects uploaded to the bucket are not being transitioned to Glacier after 90 days. What is the most likely cause of this issue?

Accepted Answer

The lifecycle policy requires additional KMS permissions to transition SSE-KMS encrypted objects.. When objects are encrypted with SSE-KMS, S3 lifecycle transitions to Glacier require the lifecycle role to have permissions to decrypt the object with the KMS key and re-encrypt it with the destination storage class's key. If the KMS key policy or the lifecycle execution role lacks these permissions, the transition silently fails. This is the most likely cause of objects not moving to Glacier after 90 days.

Answer

The bucket has S3 Versioning enabled, and the lifecycle policy does not apply to previous versions.

Answer

The bucket's default encryption setting overwrites the lifecycle policy.

Answer

The bucket has S3 Object Lock enabled, which prevents objects from being transitioned to Glacier.

Question 6

A company runs a containerized application on Amazon ECS with the Fargate launch type. The application is deployed across two Availability Zones and uses an Application Load Balancer (ALB) to distribute traffic. The application stores state in an Amazon ElastiCache Redis cluster. Recently, the development team deployed a new version of the application that introduced a memory leak. The leak causes the ECS tasks to consume more memory over time until they are OOM-killed. The SysOps administrator is asked to ensure that the application remains available and responsive. The administrator has configured an ECS service auto scaling based on average CPU utilization, but the memory leak causes tasks to fail before CPU utilization triggers scaling. Which action should the administrator take to automatically detect and replace failing tasks?

Accepted Answer

Create a custom CloudWatch metric for memory utilization and configure an ECS service auto scaling with a step scaling policy that adds tasks when memory exceeds a threshold.. Creating a custom CloudWatch metric for memory utilization (e.g., from the CloudWatch agent) and configuring an ECS service auto scaling with a step scaling policy that adds tasks when memory exceeds a threshold allows scaling out before tasks are OOM-killed. Option A is wrong because increasing the task memory limit does not prevent the leak; it only delays failure. Option B is wrong because CPU-based scaling does not address memory issues. Option C is wrong because an ALB health check only detects HTTP failures, not memory exhaustion if the process is still responding.

Answer

Increase the task memory limit to the maximum allowed for the Fargate task size. This will prevent OOM-kills.

Answer

Configure an ECS service auto scaling with a target tracking policy based on average CPU utilization. Set the target value to 50%.

Answer

Configure the ALB health check to use a more sensitive path that fails when memory is low. The ECS service will automatically replace unhealthy tasks.

Question 7

A company has a production AWS account with multiple IAM users. The SysOps administrator needs to ensure that all IAM users have multi-factor authentication (MFA) enabled for console access. If a user does not have MFA enabled, they should be denied access to all AWS services except for the ability to enable MFA on their own account. The administrator has created an IAM policy that denies all actions if MFA is not present, but the policy is not working as expected; users without MFA can still access the S3 console. The administrator attaches the policy to all users. What is the most likely reason the policy is not effective?

Accepted Answer

The policy's condition is not properly configured to check for MFA. The condition should use 'aws:MultiFactorAuthPresent' with a value of 'false'.. The correct condition key for MFA enforcement in IAM policies is aws:MultiFactorAuthPresent, and to deny access when MFA is absent you must use a Bool condition with value 'false' (or use Null to check for absence). If the policy uses the wrong key or the wrong boolean value, the Deny never matches and users retain access. The question states the policy denies all actions if MFA is not present but is not working, pointing to a misconfigured condition.

Answer

The policy includes an Allow statement that grants access to all services, which overrides the Deny statement.

Answer

The policy uses the condition key 'aws:MFAPresent' instead of 'aws:MultiFactorAuthPresent'.

Answer

The policy is attached to an IAM group, but the users are not members of that group.

Question 8

A company runs a stateless API on Amazon EC2 instances in an Auto Scaling group that spans two Availability Zones. The SysOps administrator must configure the group so that the application remains available if one Availability Zone fails, without over-provisioning instances during normal operation. The group currently has a minimum size of 2 and a maximum size of 6, with a desired capacity of 4. Which configuration change should the administrator make?

Accepted Answer

Distribute the desired capacity evenly across the two Availability Zones and ensure each zone can handle the full load.. The correct approach is to ensure the Auto Scaling group is balanced across both Availability Zones and that each zone has sufficient capacity to carry the full application load. That way, a zone failure does not reduce total capacity below what is needed. Simply raising the maximum size or enabling rebalancing without adjusting effective per-zone capacity does not achieve the required resilience.

Answer

Enable AZ rebalancing and set the desired capacity to 2.

Answer

Configure the group to use only one Availability Zone and rely on EC2 Auto Recovery.

Answer

Increase the maximum size to 12 and leave the desired capacity at 4.

Question 9

A SysOps administrator manages a production Amazon RDS for PostgreSQL DB instance. The company requires a recovery point objective (RPO) of 5 minutes and a recovery time objective (RTO) of 1 hour. The database is currently a Single-AZ deployment with automated backups retained for 7 days. Which change should the administrator implement to meet both the RPO and RTO requirements?

Accepted Answer

Convert the DB instance to a Multi-AZ deployment and enable automated backups with a 7-day retention period.. Multi-AZ deployment maintains a synchronous standby that can take over automatically with minimal data loss, satisfying the tight RPO and RTO. Automated backups with point-in-time recovery provide an additional safety net for logical errors, but the standby is what ensures high availability and rapid failover. The other options either rely on asynchronous replication or manual processes that cannot meet the required objectives.

Answer

Take manual snapshots every 5 minutes using a scheduled Lambda function.

Answer

Increase the automated backup retention period to 35 days and keep the Single-AZ configuration.

Answer

Enable a read replica in a different Availability Zone and promote it during a failure.

Question 10

An application uses an Amazon DynamoDB table with on-demand capacity. The SysOps administrator needs to ensure the table remains available during an AWS regional outage. Which strategy should be used?

Accepted Answer

Use DynamoDB global tables.. DynamoDB global tables provide multi-region, multi-active replication, ensuring the table remains available during an AWS regional outage by automatically replicating data across selected AWS Regions. This is the only option that addresses regional fault tolerance by design, as it uses DynamoDB's built-in replication to maintain availability and data durability across regions.

Answer

Enable DynamoDB Accelerator (DAX).

Answer

Create a read replica in another region.

Answer

Increase read and write capacity units.

Question 11

A SysOps administrator is testing the failover of an Amazon RDS for PostgreSQL Multi-AZ DB instance. The application currently writes to the primary instance in us-east-1a. Which action will manually trigger a failover to the standby instance in us-east-1b?

Accepted Answer

Reboot the DB instance and select 'Reboot with failover'.. The 'Reboot with failover' option in the Amazon RDS console explicitly triggers a failover by rebooting the primary DB instance and forcing the Multi-AZ configuration to promote the standby instance in us-east-1b to become the new primary. This is the designed method for manually testing or initiating a failover in a Multi-AZ deployment.

Answer

Modify the DB instance to Single-AZ and then back to Multi-AZ.

Answer

Reboot the DB instance without selecting any failover option.

Answer

Promote the standby instance using the Amazon RDS console.

Question 12

A company runs a web application on Amazon EC2 instances in a single Availability Zone. The SysOps administrator wants to increase the availability of the application so that it can survive an Availability Zone failure. Which action is the most effective?

Accepted Answer

Launch EC2 instances in two different Availability Zones and place them behind an Application Load Balancer.. Deploying EC2 instances across two different Availability Zones and placing them behind an Application Load Balancer (ALB) provides fault isolation. If one AZ fails, the ALB automatically routes traffic to the healthy instances in the other AZ, ensuring the application remains available. This architecture directly addresses the goal of surviving an AZ failure by eliminating the single point of failure at the AZ level.

Answer

Deploy an additional EC2 instance in the same Availability Zone.

Answer

Enable termination protection on all EC2 instances.

Answer

Use an Amazon RDS Multi-AZ deployment for the database tier.

Question 13

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?

Accepted Answer

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. 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.

Answer

Use an Application Load Balancer with an Auto Scaling group and a launch configuration that includes the Elastic IP

Answer

Create a CloudFormation template that launches a new instance and associates the Elastic IP

Answer

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

Question 14

A company runs a critical production database on Amazon RDS for MySQL with a Multi-AZ deployment. The database experiences a primary instance failure. The SysOps administrator needs to understand exactly how the failover process worked and why the application experienced a longer-than-expected downtime. Which AWS service or feature should the administrator use to review detailed events and actions during the failover?

Accepted Answer

AWS Personal Health Dashboard. AWS Personal Health Dashboard provides a personalized view of the health of AWS services and resources, including detailed event logs for RDS Multi-AZ failovers. It surfaces the exact sequence of actions (e.g., DNS record update, failover initiation, completion) and any underlying AWS infrastructure issues that caused the extended downtime, such as degraded hardware or network latency. This is the correct tool because it gives the administrator a chronological, AWS-side account of the failover process, which is not available through other services.

Answer

Amazon RDS Performance Insights

Answer

Amazon CloudWatch Logs

Answer

AWS CloudTrail

Question 15

A company runs a stateless web application on Amazon EC2 instances in an Auto Scaling group with a minimum of 2 and maximum of 10 instances. The instances are behind an Application Load Balancer (ALB). The SysOps administrator needs to ensure that the application can survive the failure of an entire AWS Availability Zone (AZ) in the region. Which configuration is necessary?

Accepted Answer

Configure the Auto Scaling group with subnets in at least two Availability Zones and ensure the ALB has subnets in the same AZs.. Deploying the Auto Scaling group across multiple Availability Zones (AZs) and ensuring the ALB has subnets in the same AZs allows the application to continue serving traffic even if one entire AZ fails. The ALB can route requests to healthy instances in the remaining AZs, and the Auto Scaling group will replace failed instances in other AZs as needed, maintaining the minimum instance count. This architecture is a fundamental pattern for high availability in AWS.

Answer

Increase the Auto Scaling group minimum to 10 instances to absorb the failure.

Answer

Use larger instance types to handle the load of a failed AZ.

Answer

Use multiple Application Load Balancers in different AZs.