Compute

EC2

Focused AWS Solutions Architect Associate notes from the Compute domain.

ec2#

Amazon EC2 Overview#

  • Definition: Elastic Compute Cloud (EC2) is a web service that provides scalable compute capacity in the cloud.
  • Key Concepts:
    • Instances: Virtual servers running in AWS.
    • AMIs (Amazon Machine Images): Templates for instance OS and software.
    • Instance Types: Variations in CPU, memory, storage, and networking.
  • Use Cases: Web hosting, app servers, batch processing, machine learning.

1. EC2 Instance Types#

EC2 offers families optimized for different workloads, critical for performance and cost optimization.

General Purpose (e.g., T3, M5)#

  • Purpose: Balanced compute, memory, and networking.
  • Examples: T3 (burstable), M5 (consistent performance).
  • Use Case: Web servers, small databases.

Compute Optimized (e.g., C5)#

  • Purpose: High-performance CPU.
  • Features: Ideal for compute-intensive tasks.
  • Use Case: Gaming servers, scientific modeling.

Memory Optimized (e.g., R5)#

  • Purpose: Large memory capacity.
  • Features: High memory-to-CPU ratio.
  • Use Case: In-memory databases (e.g., Redis), big data analytics.

Storage Optimized (e.g., I3, D2)#

  • Purpose: High I/O or dense storage.
  • Features: NVMe SSDs (I3) or HDDs (D2).
  • Use Case: NoSQL databases, data warehousing.

Accelerated Computing (e.g., G4, P3)#

  • Purpose: GPU/FPGA acceleration.
  • Features: High-performance graphics or ML.
  • Use Case: Machine learning, video rendering.

Key Notes:#

  • Performance: Match instance type to workload (e.g., C5 for CPU-bound apps).
  • Exam Tip: Memorize family purposes (e.g., “C” for compute).

2. EC2 Storage Options#

EC2 integrates with various storage types for resilience and performance.

Elastic Block Store (EBS)#

  • Purpose: Persistent block storage for EC2.
  • Types:
    • gp3: General-purpose SSD (cost-effective, configurable IOPS).
    • gp2: General-purpose SSD (older, IOPS tied to size).
    • io1/io2: Provisioned IOPS SSD (high performance).
    • st1: Throughput-optimized HDD (big data).
    • sc1: Cold HDD (infrequent access).
  • Features: Snapshots, encryption, Multi-Attach (io1/io2).
  • Use Case: Databases, boot volumes.

Instance Store#

  • Purpose: Temporary block storage.
  • Features: Physically attached to host, lost on stop/termination.
  • Use Case: Caches, scratch data.
  • Note: Ephemeral, not resilient.

EFS (Elastic File System)#

  • Purpose: Shared file storage for multiple EC2 instances.
  • Features: NFS protocol, scales automatically.
  • Use Case: Content management, shared workloads.

Key Notes:#

  • Resilience: EBS snapshots for backups, EFS for multi-instance access.
  • Exam Tip: Compare EBS vs. Instance Store durability.

3. EC2 Security#

Security is a key focus for SAA-C03.

Security Groups#

  • Purpose: Virtual firewall for instances.
  • Features: Stateful, allow rules only (no deny).
  • Example: Allow port 80 from 0.0.0.0/0 for web traffic.
  • Use Case: Control inbound/outbound traffic.

IAM Roles#

  • Purpose: Grant EC2 instances permissions.
  • Features: Attach role to instance, no static credentials.
  • Use Case: Allow EC2 to access S3 buckets.

Key Pairs#

  • Purpose: SSH access to instances.
  • Features: Public key stored by AWS, private key with user.
  • Note: Lost private key = no access.

Key Notes:#

  • Secure Design: Use least privilege in IAM roles, restrict security groups.
  • Exam Tip: Practice security group rules for scenarios.

4. EC2 Resilience Features#

Resilience ensures high availability and fault tolerance.

Auto Scaling#

  • Purpose: Automatically adjust instance count.
  • Components:
    • Launch Template: Defines instance config (AMI, type).
    • Scaling Policies: Target tracking (e.g., CPU at 50%), step scaling.
  • Use Case: Handle traffic spikes.

Elastic Load Balancing (ELB)#

  • Types:
    • Application Load Balancer (ALB): HTTP/HTTPS, path-based routing.
    • Network Load Balancer (NLB): TCP/UDP, low latency.
    • Classic Load Balancer: Legacy.
  • Features: Distributes traffic across instances.
  • Use Case: High availability web apps.

Placement Groups#

  • Types:
    • Cluster: Low-latency group in single AZ.
    • Spread: Instances across distinct hardware (max 7 per AZ).
    • Partition: Multiple partitions per AZ (e.g., Hadoop).
  • Use Case: Optimize performance or resilience.

Key Notes:#

  • Resilience: Auto Scaling + ELB for multi-AZ deployments.
  • Exam Tip: Know when to use Spread vs. Cluster.

5. EC2 Performance Features#

High-performing architectures leverage EC2 optimizations.

Enhanced Networking#

  • Purpose: Higher bandwidth, lower latency.
  • Options: Elastic Network Adapter (ENA), Elastic Fabric Adapter (EFA).
  • Use Case: HPC, big data.

Instance Type Selection#

  • Purpose: Match workload to resources.
  • Example: C5 for CPU-heavy tasks, R5 for memory-intensive.

EBS Optimization#

  • Purpose: Improve I/O performance.
  • Features: Enabled by default on many instances.
  • Use Case: Databases with high IOPS.

Key Notes:#

  • Performance: Enhanced Networking + right instance type.
  • Exam Tip: Identify workload needs in scenarios.

6. EC2 Cost Optimization#

Cost optimization is critical for SAA-C03.

Pricing Models#

  • On-Demand: Pay per hour/second, no commitment.
  • Reserved Instances (RI): 1- or 3-year commitment, up to 72% savings.
  • Spot Instances: Bid on unused capacity, up to 90% savings.
  • Savings Plans: Flexible RI alternative.
  • Dedicated Hosts: Physical server, per-host billing.

Spot Fleet#

  • Purpose: Manage multiple Spot Instances.
  • Features: Diversifies across instance types/AZs.
  • Use Case: Batch processing.

Auto Scaling#

  • Purpose: Scale down to reduce costs.
  • Use Case: Shut down unused instances overnight.

Key Notes:#

  • Cost Savings: Spot for interruptible workloads, RI for steady-state.
  • Exam Tip: Calculate costs for mixed pricing scenarios.

7. EC2 Networking#

Networking integrates EC2 with VPCs.

Elastic Network Interface (ENI)#

  • Purpose: Virtual NIC for instances.
  • Features: Attach multiple ENIs, move between instances.
  • Use Case: Failover, multi-IP setups.

Elastic IP (EIP)#

  • Purpose: Static public IP.
  • Features: Reassignable, no charge when attached.
  • Use Case: Persistent public access.

VPC Integration#

  • Purpose: Place EC2 in private/public subnets.
  • Features: Route tables, NAT Gateway for outbound.
  • Use Case: Secure app tier in private subnet.

Key Notes:#

  • Networking: ENI for flexibility, EIP for consistency.
  • Exam Tip: Design VPC with EC2 placement.

8. EC2 Use Cases#

Understand practical applications.

Web Hosting#

  • Setup: EC2 + ALB + Auto Scaling.
  • Features: Scalable, resilient web servers.

Batch Processing#

  • Setup: Spot Instances + SQS.
  • Features: Cost-effective, fault-tolerant.

High-Performance Computing (HPC)#

  • Setup: Cluster placement group + C5 instances.
  • Features: Low-latency, high CPU.

Key Notes:#

  • Versatility: EC2 fits many roles with proper config.
  • Exam Tip: Match use case to features.

Quick Reference Table#

FeaturePurposeKey DetailExam Relevance
Instance TypesWorkload optimizationT3, C5, R5, etc.Performance, Cost
EBSPersistent storagegp3, io2, snapshotsResilience, Performance
Security GroupsTraffic controlStateful, allow-onlySecurity
Auto ScalingDynamic scalingLaunch templates, policiesResilience, Cost
ELBLoad distributionALB, NLBResilience, Performance
Pricing ModelsCost managementSpot, RI, On-DemandCost Optimization
Enhanced NetworkingBetter performanceENA, EFAPerformance
ENI/EIPNetworking flexibilityMultiple IPs, static addressingNetworking, Resilience

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