AWS service comparisons

Many exam questions come down to choosing between two or three services that sound alike. Each page puts them side by side, says when to pick which, and lists the traps, with free practice questions to test it.

• ALB vs NLB vs Gateway Load Balancer

  The Application Load Balancer routes HTTP requests by content, the Network Load Balancer handles TCP and UDP with static IPs and very low latency, and the Gateway Load Balancer inserts firewall appliances. Which to pick and why.

• CloudFront vs Global Accelerator

  Amazon CloudFront caches HTTP content at edge locations; AWS Global Accelerator gives two static anycast IPs and routes TCP and UDP traffic over the AWS network to the healthiest Regional endpoint. When to use each.

• CloudTrail vs CloudWatch vs AWS Config

  CloudTrail records who called which AWS API, CloudWatch watches performance through metrics, logs and alarms, and AWS Config tracks how resources are configured and whether they comply with rules. Which service answers which question.

• Cognito user pools vs identity pools

  An Amazon Cognito user pool signs users in and issues JWTs; an identity pool exchanges a sign-in for temporary AWS credentials. What each does and when an app needs one or both.

• EFS vs FSx vs S3

  Amazon EFS is a shared Linux file system, the FSx family covers Windows, high-performance and NetApp workloads, and S3 is object storage accessed through an API. Which storage fits which scenario.

• Kinesis Data Streams vs Amazon Data Firehose

  Kinesis Data Streams stores ordered records for your own real-time consumers to replay; Amazon Data Firehose loads streaming data into S3, Redshift and other destinations with no code. How to choose, and the exam traps.

• RDS vs Aurora vs DynamoDB

  Amazon RDS runs familiar relational engines, Aurora is AWS's cloud-built MySQL and PostgreSQL-compatible database, and DynamoDB is serverless key-value NoSQL. When to choose each for the exam.

• Savings Plans vs Reserved Instances vs Spot Instances

  Savings Plans and Reserved Instances cut prices for steady use in exchange for a one- or three-year commitment; Spot Instances use spare capacity at up to 90% off but can be interrupted. How to pick the right EC2 pricing option.

• Secrets Manager vs Parameter Store

  AWS Secrets Manager stores secrets with built-in automatic rotation and cross-account sharing; Systems Manager Parameter Store keeps configuration and secure strings cheaply, without rotation. Which one a question wants.

• Security groups vs network ACLs

  Security groups are stateful allow-only firewalls on each network interface; network ACLs are stateless subnet-level rules that can also deny. How they differ and which one a question needs.

• SQS vs SNS vs EventBridge

  Amazon SQS queues work for one consumer to pull, SNS pushes copies to many subscribers, and EventBridge routes events by their content. When to use each, ordering, retention and the exam traps.

• VPC peering vs Transit Gateway vs PrivateLink

  VPC peering links two VPCs directly, Transit Gateway is a hub that connects many VPCs and on-premises networks, and PrivateLink exposes a single service privately, even across overlapping IP ranges. How to choose.