Databases, App Integration, Management, Migration

Question 1

What is Amazon RDS?

Answer 1

Relational Database Service – managed relational DB service. Supports MySQL, PostgreSQL, MariaDB, Oracle, MS SQL Server, Aurora. AWS handles patching, backups, hardware provisioning, replication.

Question 2

What are the key features of RDS?

Answer 2

Multi-AZ (synchronous standby, HA not read scaling), Read Replicas (async, up to 5, for read scaling), Automated Backups (1-35 day retention), Manual Snapshots (retained until deleted), Encryption at rest (KMS) and in transit (SSL).

Question 3

What is RDS Multi-AZ and what is it for?

Answer 3

A synchronous standby replica in a different AZ. Provides automatic failover for high availability. NOT used for read scaling – that is what Read Replicas are for.

Question 4

What is RDS Read Replicas and what is it for?

Answer 4

Asynchronous copies of the primary database (up to 5). Used to scale read traffic. Can be in the same region, cross-region, or promoted to standalone DB.

Question 5

What is Amazon Aurora?

Answer 5

AWS-proprietary relational DB engine. MySQL and PostgreSQL compatible. 5× faster than MySQL, 3× faster than PostgreSQL. Storage auto-scales 10GB–128TB. Aurora Serverless: auto-scales compute. Aurora Global Database: multi-region with sub-second replication.

Question 6

What is Amazon DynamoDB?

Answer 6

Fully managed NoSQL database (key-value + document). Single-digit millisecond latency at any scale. Serverless. Scales to petabytes and millions of requests/second. Tables contain items (like rows) with attributes.

Question 7

What are the key DynamoDB concepts?

Answer 7

Table, Items (rows), Attributes (columns – flexible schema). Primary Key: Partition Key (required) + optional Sort Key. DynamoDB Streams: capture item changes. DAX: in-memory microsecond cache. Global Tables: multi-region multi-master.

Question 8

What is DynamoDB DAX?

Answer 8

DynamoDB Accelerator – an in-memory cache for DynamoDB delivering microsecond read latency (vs milliseconds without DAX).

Question 9

What is Amazon Redshift?

Answer 9

Fully managed petabyte-scale data warehouse. SQL-compatible, OLAP (Online Analytical Processing). Based on PostgreSQL. Great for running analysis and aggregation on large datasets. Redshift Spectrum: query S3 data without loading it in.

Question 10

What is Amazon ElastiCache?

Answer 10

Managed in-memory caching. Redis: rich data structures, persistence, replication, cluster mode. Memcached: simple, multi-threaded, horizontal scaling. Use cases: DB query caching, session storage, real-time leaderboards.

Question 11

SQL vs NoSQL databases – key differences?

Answer 11

SQL: structured/schema, ACID properties, vertically scaled, uses SQL. | NoSQL: unstructured/schema-less, BASE properties (basically available, soft state, eventual consistency), horizontally scaled.

Question 12

What are the specialty AWS database services?

Answer 12

DocumentDB (MongoDB-compatible, JSON documents), Neptune (graph DB, social networks), QLDB (immutable ledger, financial transactions), Timestream (serverless time-series), Keyspaces (Cassandra-compatible, IoT/time-series), OpenSearch (Elasticsearch clone, search/analytics).

Question 13

What is AWS DMS?

Answer 13

Database Migration Service – migrates databases to AWS with minimal downtime and zero data loss. Supports homogeneous migrations (same engine) and heterogeneous (different engine).

Question 14

What is AWS SCT?

Answer 14

Schema Conversion Tool – converts database schema from one engine to another (e.g. Oracle to PostgreSQL). Used alongside DMS for heterogeneous migrations.

Question 15

Self-managed vs managed databases – trade-offs?

Answer 15

Self-managed: full control, but you handle backups, HA, replication, patching, and scaling – high operational overhead. | Managed (RDS, Aurora): AWS handles infrastructure, HA, patching, backups – reduced control but far lower overhead.

Question 16

What is Amazon SQS?

Answer 16

Simple Queue Service – fully managed message queue. Decouples application components. Messages retained up to 14 days. Standard Queue: best-effort ordering, at-least-once delivery, unlimited throughput. FIFO Queue: exactly-once, ordered, up to 3,000 msg/sec.

Question 17

What is Amazon SNS?

Answer 17

Simple Notification Service – pub/sub messaging. One published message fans out to many subscribers simultaneously. Protocols: Email, SMS, HTTP/HTTPS, Lambda, SQS, Mobile Push. No message persistence.

Question 18

SQS vs SNS – full comparison?

Answer 18

SQS: queue (pull model), one consumer per message, persists up to 14 days, used for decoupling/buffering. | SNS: topic (push/fan-out), multiple subscribers receive same message, no persistence, used for broadcasts/notifications.

Question 19

What is Amazon EventBridge?

Answer 19

Serverless event bus for event-driven applications (formerly CloudWatch Events). Routes events between AWS services, SaaS apps, and custom apps using rules and event patterns. Supports cron/scheduled events.

Question 20

What is Amazon Kinesis?

Answer 20

Real-time data streaming. Kinesis Data Streams: capture/process/store data streams. Kinesis Data Firehose: load streaming data to S3/Redshift/OpenSearch. Kinesis Data Analytics: SQL or Flink analysis of streams. Use cases: IoT, log analytics, clickstream.

Question 21

What is AWS Step Functions?

Answer 21

Serverless visual workflow service. Coordinates multiple AWS services into state-machine workflows defined in Amazon States Language (JSON). Used to orchestrate Lambda functions, ETL jobs, and ML pipelines.

Question 22

What is Amazon API Gateway?

Answer 22

Fully managed service to create, publish, and maintain REST and WebSocket APIs. Integrates with Lambda, EC2, HTTP endpoints. Features: authentication, throttling, caching, monitoring.

Question 23

What is Elastic Load Balancing (ELB) in the context of application integration?

Answer 23

Distributes incoming traffic across multiple backend targets (EC2, ECS, EKS, Lambda). Acts as a single point of contact for clients. Works with Auto Scaling to handle varying load.

Question 24

What is Amazon MQ?

Answer 24

A managed message broker service for Apache ActiveMQ and RabbitMQ. For migrating existing applications that use these protocols without re-writing them to use SQS/SNS.

Question 25

What is AWS AppFlow?

Answer 25

Used to integrate data between SaaS applications and AWS services without writing code.

Question 26

What is Amazon CloudWatch?

Answer 26

Monitoring and observability service. Components: Metrics (time-series data), Logs (CloudWatch Logs), Alarms (trigger actions on thresholds), Dashboards (visualise metrics/logs), Log Insights (query logs), Container Insights (ECS/EKS/K8s monitoring).

Question 27

What are CloudWatch Alarms?

Answer 27

Trigger actions when a metric exceeds a threshold. Actions include: send SNS notification, trigger Auto Scaling, or invoke a Lambda function.

Question 28

What does AWS CloudTrail record and how?

Answer 28

Records all API calls in your AWS account: who did what, when, and from where. Includes management events (create/modify/delete), data events (S3 object-level, Lambda invoke), and insights events (unusual activity). Logs stored in S3. Default: 90-day event history in console without a trail.

Question 29

What is AWS Systems Manager?

Answer 29

Operations hub for AWS and on-premises resources. Key features: Session Manager (SSH/RDP without open ports or bastion hosts), Parameter Store (secure config/secrets storage), Patch Manager (automate OS patching), Automation (runbooks), Run Command (remote commands on multiple instances), Inventory (instance metadata).

Question 30

What is AWS Config?

Answer 30

Assesses, audits, and evaluates resource configurations for compliance. Configuration History tracks changes over time. Rules evaluate compliance policies (e.g. 'all S3 buckets must have encryption'). Supports auto-remediation of non-compliant resources.

Question 31

What is AWS Trusted Advisor?

Answer 31

Real-time guidance to provision resources following AWS best practices. 5 categories: Cost Optimisation, Performance, Security, Fault Tolerance, Service Limits. Basic/Developer: 6 core checks. Business/Enterprise: all ~140 checks.

Question 32

What is the AWS Health Dashboard?

Answer 32

Personalised view of AWS service health. Service Health: real-time status of all AWS services globally. Account Health: events specifically affecting your resources. Proactive notifications for planned maintenance. Available to all accounts at no cost.

Question 33

What is AWS OpsWorks?

Answer 33

Configuration management service providing managed instances of Chef and Puppet. Used to automate server configuration through code.

Question 34

What is AWS Service Catalog?

Answer 34

Allows organisations to create and manage catalogues of approved CloudFormation/Terraform templates that teams can use to deploy resources in a controlled, self-service way.

Question 35

What is AWS Control Tower?

Answer 35

Helps set up and govern a multi-account AWS environment following best practices. Builds on AWS Organizations and adds auditing, logging, and compliance guardrails.

Question 36

What are the 7 Rs of cloud migration?

Answer 36

Retire: decommission unused apps. | Retain: keep on-prem for now. | Rehost (Lift & Shift): move without changes. | Relocate: move to cloud hypervisor (e.g. VMware Cloud on AWS). | Replatform (Lift, Tinker & Shift): minor optimisations. | Repurchase: switch to SaaS. | Refactor/Re-architect: redesign as cloud-native.

Question 37

What is Rehosting (Lift and Shift)?

Answer 37

Moving an application to the cloud without making any changes. Allows companies to migrate quickly at scale. Example: move a VM directly to EC2.

Question 38

What is Replatforming?

Answer 38

Making a few cloud optimisations to gain tangible benefit without changing the core architecture. Example: move a self-managed DB to RDS.

Question 39

What is Refactoring/Re-architecting?

Answer 39

Reimagining how an application is architected using cloud-native features. Driven by need to add features, scale, or performance difficult to achieve in the existing environment. Example: migrate monolith to microservices. Highest effort, highest benefit.

Question 40

What is Repurchasing?

Answer 40

Moving from a traditional licence to a SaaS model. Example: migrating from a self-hosted CRM to Salesforce.

Question 41

What are the 6 perspectives of the AWS Cloud Adoption Framework (CAF)?

Answer 41

Business (value, risk), People (training, change management), Governance (portfolio, programme management), Platform (architecture, provisioning), Security (IAM, data protection), Operations (monitor, operate, manage).

Question 42

What is AWS Migration Hub?

Answer 42

Central location to track and manage migration progress across AWS migration services.

Question 43

What is AWS Application Discovery Service?

Answer 43

Discovers on-premises servers, maps dependencies, and gathers data to help plan cloud migrations.

Question 44

What is AWS Application Migration Service (MGN)?

Answer 44

Performs lift-and-shift server migrations by continuously replicating source servers to AWS and enabling test/live cutover with minimal downtime.

Question 45

What is AWS DataSync?

Answer 45

Automates and accelerates online data transfer between on-premises storage (NFS, SMB) and AWS storage services (S3, EFS, FSx). Encrypted in transit.

Question 46

What is the AWS Transfer Family?

Answer 46

Managed SFTP, FTPS, FTP, and AS2 file transfer service that connects to S3 or EFS backends.

Question 47

What is AWS Elastic Disaster Recovery?

Answer 47

Minimises downtime and data loss with fast recovery of on-premises and cloud-based applications using affordable storage, minimal compute, and point-in-time recovery.