Architecting on AWS Certification Architecting on AWS Certification High Availability & Fault Tolerance 3

Question 1

Which AWS service enables you to create a pilot-light disaster recovery strategy by maintaining a minimal version of your environment running in a secondary Region?

Accepted Answer

AWS Elastic Disaster Recovery

Answer

AWS Backup

Answer

AWS CloudFormation StackSets

Answer

Amazon Data Lifecycle Manager

Question 2

Which CloudWatch metric would an architect monitor to detect that an Application Load Balancer has no healthy targets available?

Accepted Answer

HealthyHostCount

Answer

RequestCount

Answer

TargetResponseTime

Answer

HTTPCode_ELB_5XX_Count

Question 3

An application must maintain session state even if the EC2 instance serving a user is replaced. Which solution achieves this with the least application change?

Accepted Answer

Store sessions in Amazon ElastiCache

Answer

Store sessions in an EC2 instance store

Answer

Use sticky sessions on the load balancer

Answer

Write sessions to local disk with snapshots

Question 4

What RTO (Recovery Time Objective) characteristic distinguishes a warm standby DR strategy from a pilot light strategy?

Accepted Answer

Warm standby has a shorter RTO because a scaled-down but fully functional environment is already running

Answer

Warm standby has a longer RTO because more services need to start

Answer

Both strategies have the same RTO

Answer

Warm standby requires more manual steps than pilot light

Question 5

Which AWS Global Infrastructure feature ensures that an EC2 instance placed in a specific Availability Zone is physically isolated from instances in other AZs within the same Region?

Accepted Answer

AZ physical separation

Answer

VPC peering

Answer

Placement groups

Answer

Security groups

Question 6

An architect designs a multi-AZ architecture for an RDS database. Which statement about automated failover is correct?

Accepted Answer

Failover updates the DB endpoint DNS record to point to the standby

Answer

Failover requires a manual snapshot restore

Answer

Failover requires the application connection string to change

Answer

Failover takes approximately 30 minutes to complete