🎯 DVA-C02 — Exam Tips & Ultimate Cheatsheet

Use this page for your final review the day before the exam.

⚡ Keyword → Service Mapping

Keyword in question	Answer
Serverless	Lambda, DynamoDB, S3, API Gateway, Step Functions
No servers to manage	Lambda (code), Fargate (containers)
Decouple	SQS (queue), SNS (pub/sub), EventBridge
Real-time streaming	Kinesis Data Streams
Load streaming to S3	Kinesis Data Firehose
Fan-out	SNS → multiple SQS queues
Ordered messages	SQS FIFO or Kinesis (per shard)
Exactly-once delivery	SQS FIFO
Cache	ElastiCache Redis/Memcached, DAX (DynamoDB only)
Leaderboard / sorted data	ElastiCache Redis Sorted Sets
Sub-millisecond reads	DAX (DynamoDB)
Audit trail / who called what	CloudTrail
App performance metrics	CloudWatch
Distributed tracing	X-Ray
Secrets with auto-rotation	Secrets Manager
Configuration / cheap secrets	SSM Parameter Store
Encrypt data > 4KB	KMS Envelope Encryption (GenerateDataKey)
Cross-account access	IAM Role with trust policy + AssumeRole
Confused deputy protection	STS ExternalId
User auth (sign in to app)	Cognito User Pool
AWS credentials for users	Cognito Identity Pool
Custom JWT claims	Cognito Pre Token Generation trigger
Direct S3 upload from browser	S3 Presigned PUT URL
S3 bucket encryption audit	SSE-KMS (CloudTrail logs KMS calls)
S3 query without download	S3 Select
Prevent S3 accidental delete	S3 MFA Delete or Object Lock
Immutable Lambda deployment	Lambda Version + Alias
Gradual Lambda traffic shift	CodeDeploy Canary/Linear + Lambda Alias
API throttling per customer	API Gateway Usage Plans + API Keys
API response caching	API Gateway REST API cache
API max timeout	29 seconds (API Gateway hard limit)
Blue/Green on EC2	CodeDeploy or Elastic Beanstalk
IaC serverless	SAM (`Transform: AWS::Serverless-2016-10-31`)
IaC general	CloudFormation
Multi-account IaC	CloudFormation StackSets
Human approval in pipeline	CodePipeline Manual Approval
Background jobs from web tier	SQS + Worker tier (Beanstalk)
Orchestrate multi-step workflows	Step Functions
Long workflow (> 5 min)	Step Functions Standard
Short high-volume workflow	Step Functions Express
Human approval in workflow	Step Functions Callback (waitForTaskToken)
EC2 RAM metric	CloudWatch Agent (not default!)
Cold starts for Java Lambda	SnapStart, Provisioned Concurrency
Lambda shares code/libraries	Lambda Layers
Container without EC2 mgmt	ECS Fargate
Container app permissions	ECS Task Role (not Execution Role!)

🪤 Common Exam Traps

Trap	Correct Answer
"Lambda retries on S3 event failure"	2 retries (async), not 3
"SQS visibility timeout too short"	Messages processed twice
"EC2 MemoryUtilization alarm shows no data"	CloudWatch Agent not installed
"Secrets Manager vs Parameter Store"	Secrets Manager = rotation; SSM = cheap config
"DLQ vs Destinations"	Destinations = success + failure, more targets (prefer it)
"Lambda $LATEST in production"	Never — use published version + alias
"KMS encrypt large file"	Envelope encryption — KMS max 4KB
"CloudTrail vs CloudWatch"	CloudTrail = API calls; CloudWatch = metrics/logs
"Cognito User Pool vs Identity Pool"	User Pool = sign in; Identity Pool = AWS credentials
"ECS Task Role vs Execution Role"	Task Role = app perms; Execution Role = ECS agent perms
"SNS alone for job processing"	SNS has no retention — use SNS → SQS for reliability
"Standard Queue ordering"	Best-effort — use FIFO for guaranteed order
"Kinesis vs SQS for replay"	Kinesis supports replay; SQS messages deleted after consume
"API Gateway timeout"	29 seconds — NOT Lambda's 15 minutes
"SAM transform declaration"	`AWS::Serverless-2016-10-31` NOT `AWS::SAM-2016-10-31`

📊 Domain-Specific Priorities

Domain 1 — Development (32%)

Must-know services: Lambda, DynamoDB, S3, API Gateway, SQS/SNS/Kinesis, Step Functions, ElastiCache

Domain 2 — Security (26%)

Must-know services: IAM, Cognito, KMS, Secrets Manager, SSM, CloudTrail

Key patterns:

Use roles, never access keys
Least privilege
Encryption at rest + in transit
Audit everything (CloudTrail)

Domain 3 — Deployment (24%)

Must-know services: CodeCommit, CodeBuild, CodeDeploy, CodePipeline, CloudFormation, SAM, Beanstalk, ECS/Fargate

Key concepts: deployment strategies, blue/green, canary, rollback

Domain 4 — Troubleshooting & Optimization (18%)

Must-know services: CloudWatch, X-Ray, CloudTrail

Key patterns:

Metrics → Alarms → SNS actions
Logs → Metric Filters → Alarms
X-Ray Annotations for searchable traces
X-Ray Segments/Subsegments for distributed tracing

⏱️ Exam Time Management

Phase	Time
First pass (answer what you know)	~70 minutes
Review flagged questions	~40 minutes
Final review	~20 minutes
Buffer	~0 minutes (130 total)

Strategy:

Answer easy questions first (< 30 seconds)
Flag uncertain questions — don't spend > 2 min each
Eliminate wrong answers first for hard questions
Never leave blanks — guess if needed (no penalty)

🔄 Last-Minute Service Quick Facts

Service	Key Number
Lambda max timeout	15 minutes
Lambda max memory	10,240 MB
Lambda default concurrency	1,000 per region
API Gateway timeout	29 seconds
SQS standard max retention	14 days
SQS visibility timeout max	12 hours
SQS FIFO throughput	300 TPS (3,000 with batching)
DynamoDB max transaction items	100 items
DynamoDB TTL deletion SLA	within 48 hours
Kinesis default retention	24 hours (max 365 days)
Kinesis shard write	1 MB/s or 1,000 records/s
S3 presigned URL max expiry	7 days
KMS direct encrypt max size	4 KB
Cognito Access Token expiry	1 hour (default)
CloudTrail Event History	90 days
Step Functions Standard max	1 year
Step Functions Express max	5 minutes
CodeBuild cache type for Maven	S3 cache (`/root/.m2/*/`)

📚 Final Study Resources

Resource	Priority
TutorialsDojo Practice Exams	⭐⭐⭐ Must do
Stephane Maarek DVA-C02 (Udemy)	⭐⭐⭐ Must do
AWS Skill Builder Official Practice	⭐⭐ Recommended
AWS DVA-C02 Exam Guide	⭐⭐ Read once
AWS Workshops (hands-on)	⭐ Good for hands-on
Whizlabs Practice Tests	⭐ Extra practice

You've got this!

The best preparation is a combination of watching/reading all topics + hands-on practice in an AWS account + practice exams until you consistently score 80%+.

Target 80%+ on TutorialsDojo mocks before booking the real exam.

⚡ Keyword → Service Mapping​

🪤 Common Exam Traps​

📊 Domain-Specific Priorities​

Domain 1 — Development (32%)​

Domain 2 — Security (26%)​

Domain 3 — Deployment (24%)​

Domain 4 — Troubleshooting & Optimization (18%)​

⏱️ Exam Time Management​

🔄 Last-Minute Service Quick Facts​

📚 Final Study Resources​