AWS DevOps High Availability 2 — Questions and Answers
Question 1: A DevOps team needs to ensure their ECS Fargate service automatically recovers from task failures across two Availability Zones. Which configuration achieves this?
- Set minimum healthy percent to 0 and enable circuit breaker
- Set desired count to 2 with tasks spread across AZs and enable ECS service auto-scaling (Correct answer)
- Use a single AZ with ECS task restart policies
- Configure ECS capacity providers with FARGATE_SPOT only
Correct answer: Set desired count to 2 with tasks spread across AZs and enable ECS service auto-scaling
Setting desired count to 2 with AZ spread and auto-scaling ensures tasks are distributed and recovered across multiple AZs for high availability.
Question 2: Which AWS service enables you to define a Route 53 health check that automatically fails over traffic from an unhealthy primary EC2 instance to a standby instance?
- AWS Global Accelerator
- Route 53 active-passive failover with health checks (Correct answer)
- Elastic Load Balancer with cross-zone load balancing
- AWS Transit Gateway with route tables
Correct answer: Route 53 active-passive failover with health checks
Route 53 active-passive failover routing policy uses health checks to automatically redirect traffic to a standby resource when the primary becomes unhealthy.
Question 3: A multi-AZ RDS deployment experiences a primary instance failure. What is the expected recovery behavior?
- A manual snapshot must be restored to a new instance
- RDS automatically promotes the standby replica with a DNS endpoint update, typically within 1-2 minutes (Correct answer)
- The application must update its connection string to the new endpoint
- A CloudFormation stack update is needed to point to the standby
Correct answer: RDS automatically promotes the standby replica with a DNS endpoint update, typically within 1-2 minutes
Multi-AZ RDS uses synchronous replication and automatically fails over to the standby by updating the DNS CNAME, requiring no manual intervention.
Question 4: Which combination of services provides the highest availability for a stateless web application serving global users?
- Single-region ALB with EC2 Auto Scaling and CloudFront
- Multi-region ALB with Route 53 latency routing and WAF
- CloudFront with Route 53 geolocation routing and multi-region ALBs with health checks (Correct answer)
- API Gateway with Lambda in a single region and ElastiCache
Correct answer: CloudFront with Route 53 geolocation routing and multi-region ALBs with health checks
CloudFront with Route 53 health-check-based routing across multi-region ALBs provides global distribution, caching, and automatic regional failover.
Question 5: In a CodeDeploy blue/green deployment to EC2, what happens to the original (blue) instances after a successful deployment and traffic shift?
- They are immediately terminated automatically
- They remain running for a configurable wait period before termination, allowing rollback if needed (Correct answer)
- They are converted to standby instances in the Auto Scaling group
- They are deregistered from the load balancer but kept running indefinitely
Correct answer: They remain running for a configurable wait period before termination, allowing rollback if needed
CodeDeploy retains blue instances for a configurable time window after the traffic shift, enabling quick rollback before they are terminated.
Question 6: An application deployed with AWS Elastic Beanstalk must remain available during deployments with zero downtime. Which deployment policy achieves this?
- All at once
- Rolling
- Immutable
- Rolling with additional batch (Correct answer)
Correct answer: Rolling with additional batch
Rolling with additional batch launches extra instances first, ensuring full capacity is maintained throughout the deployment with no downtime.
Question 7: Which AWS feature allows DynamoDB to automatically replicate data across multiple AWS Regions for high availability and disaster recovery?
- DynamoDB Streams with Lambda replication functions
- DynamoDB Global Tables (Correct answer)
- DynamoDB on-demand backup with cross-region restore
- DynamoDB DAX with multi-region cache clusters
Correct answer: DynamoDB Global Tables
DynamoDB Global Tables provide fully managed, multi-region, multi-active replication with automatic conflict resolution.
AWS DevOps High Availability 2
A DevOps team needs to ensure their ECS Fargate service automatically recovers from task failures across two Availability Zones.
Which configuration achieves this?