Cloud Technology and Services
What you will learn
In this domain, you will learn the key AWS services across compute (EC2, Lambda), storage (S3, EBS, EFS), databases (RDS, DynamoDB), networking (VPC, Route 53), and operations (CloudWatch, CloudTrail). As the largest domain at 34% of the CLF-C02 exam, learning the correct mapping between service names and their purposes is the key to passing.
Key points
- Compute - the differences between EC2 (virtual servers), Lambda (serverless functions), and ECS / EKS (containers)
- Storage - choosing among S3 (object), EBS (block storage for EC2), EFS (shared file), and S3 Glacier (long-term archiving)
- Scalable web architectures - combining ELB (load balancing across multiple instances) with Auto Scaling (automatically adjusting the number of instances to demand)
- Application integration - SQS (message queues), SNS (publish / subscribe notifications), API Gateway (the front door for APIs), and Kinesis (real-time streaming)
- Databases - RDS (relational), DynamoDB (NoSQL), Aurora, and ElastiCache (in-memory)
- Networking - VPC is a virtual network, Route 53 is DNS, CloudFront is a CDN, and Direct Connect is a dedicated line
- Operations and monitoring - CloudWatch (metrics and logs), CloudTrail (API operation auditing), and Config (configuration change tracking)
- Deployment automation - CloudFormation (IaC) and Elastic Beanstalk (PaaS)
- Analytics - Athena (SQL queries against S3), Redshift (data warehouse), and QuickSight (BI)
Terms and concepts
Amazon EC2 and AWS Lambda
EC2 is a virtual server that you can configure freely from the OS level up and that suits long-running workloads. Lambda is an event-driven serverless function for which you only write code, with no infrastructure to manage. As a general rule, EC2 suits always-on workloads while Lambda suits intermittent processing.
→ Fundamentals of Lambda Serverless / → How to Use EC2 Instances
Amazon S3 and Amazon EBS
S3 is object storage accessed through HTTP(S) APIs. It is well suited to images, videos, and backups, and offers extremely high durability of 99.999999999% (eleven nines). EBS is block storage that you attach to EC2, suited to low-latency random access such as an OS disk or a database data area, but as a rule it can be used by only one EC2 instance at a time. S3 offers storage classes matched to access frequency, and moving rarely retrieved data to the S3 Glacier archive classes can cut storage costs dramatically.
→ Designing S3 Storage Classes / → Designing and Optimizing EBS / → Archiving Strategies with Glacier
Amazon RDS and Amazon DynamoDB
RDS is a managed service for relational databases (RDBs) such as MySQL, PostgreSQL, and Oracle, and it suits transactions and complex joins. DynamoDB is a NoSQL key-value store characterized by millisecond-level latency and virtually unlimited scaling.
Amazon VPC and Related Networking Services
A VPC is a virtual network you create within AWS, composed of subnets, route tables, and security groups. Route 53 is DNS, CloudFront is a CDN, Direct Connect is a dedicated line connecting AWS to on-premises, and VPN is an encrypted connection over the internet.
CloudWatch and CloudTrail
The two have similar names but serve different purposes. CloudWatch is a monitoring service that handles metrics, logs, and alarms. CloudTrail is an auditing service that records who called which API and when.
→ Monitoring with CloudWatch / → Audit Logging with CloudTrail
ELB and Auto Scaling
ELB (Elastic Load Balancing) is a load balancer that distributes requests across multiple EC2 instances, improving availability by spreading traffic across multiple AZs. Auto Scaling automatically adjusts the number of instances itself in response to demand. The combination - ELB spreads the load while Auto Scaling right-sizes the fleet - is the classic pattern for a scalable, highly available web architecture.
→ Choosing Among the Three ELB Types / → Auto Scaling Strategies
SQS / SNS / API Gateway (Application Integration)
SQS is a queue that temporarily holds messages, decoupling senders from receivers and absorbing bursts of work. SNS is a publish / subscribe notification service that fans a single message out to multiple destinations (email, Lambda, SQS, and so on) at once. API Gateway is a managed service that acts as the front door for REST / HTTP APIs, taking care of authentication and throttling on your behalf.
→ Message Queuing with SQS / → Publish / Subscribe with SNS / → Designing with API Gateway
Amazon Kinesis (Streaming Data)
Kinesis is a family of services for ingesting and processing continuously generated data - logs, clickstreams, IoT sensor readings - in real time. While both services "pass data along," SQS suits queuing individual messages, whereas Kinesis suits keeping a large volume of continuous data flowing in order.
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