gh-ahmedasmar-devops-claude-skills-aws-cost-optimization/references/service_alternatives.md

AWS Service Alternatives - Cost Optimization Guide

When to use cheaper alternatives and cost-effective service options for common AWS services.

Table of Contents

1. Compute Alternatives
2. Storage Alternatives
3. Database Alternatives
4. Networking Alternatives
5. Application Services

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Compute Alternatives

EC2 vs Lambda vs Fargate

EC2 (Most Economical for Consistent Workloads)

• When to use: 24/7 workloads, predictable traffic, need full OS control
• Cost model: Hourly charges, cheaper with Reserved Instances
• Best for: Always-on applications, legacy apps, specific OS/kernel requirements
• Example: Web server handling steady traffic → EC2 with Reserved Instance

Lambda (Most Economical for Intermittent Work)

• When to use: Event-driven, sporadic usage, < 15 minute executions
• Cost model: Pay per execution and duration (GB-seconds)
• Best for: APIs with sporadic traffic, scheduled tasks, event processing
• Example: Image processing triggered by S3 upload → Lambda
• Break-even: ~20-30 hours/month execution time vs equivalent EC2

Fargate (Middle Ground)

• When to use: Containerized apps, variable traffic, don't want to manage servers
• Cost model: Pay for vCPU and memory allocated
• Best for: Microservices, batch jobs, variable load applications
• Example: Background worker that scales 0-10 containers → Fargate
• Tip: Fargate Spot offers up to 70% savings for fault-tolerant tasks

Decision Matrix

Consistent 24/7 load → EC2 with Reserved Instances
Variable load, containerized → Fargate (or Fargate Spot)
Event-driven, < 15 min → Lambda
Batch processing → Fargate Spot or EC2 Spot

EC2 Instance Alternatives

Standard vs Graviton (ARM64)

• Graviton Savings: 20% cheaper for same performance
• When to use: Modern applications, ARM-compatible workloads
• Alternatives:
  • t3.large → t4g.large (20% cheaper)
  • m5.xlarge → m6g.xlarge (20% cheaper)
  • c5.2xlarge → c6g.2xlarge (20% cheaper)
• Considerations: Test application compatibility first

Current vs Previous Generation

• Migration Savings: 5-10% cheaper, better performance
• Examples:
  • t2 → t3 (10% cheaper, better performance)
  • m4 → m5 → m6i (progressive improvements)
  • c4 → c5 → c6i (better price/performance)
• Action: Check detect_old_generations.py script

On-Demand vs Spot vs Reserved

• On-Demand: $X/hour, highest cost, full flexibility
• Spot: 60-90% discount, can be interrupted
• Reserved (1yr): 30-40% discount
• Reserved (3yr): 50-65% discount
• Decision: Use Spot for fault-tolerant, RI for predictable, On-Demand for rest

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Storage Alternatives

S3 Storage Classes

Frequently Accessed Data

S3 Standard → $0.023/GB/month
Use when: Accessing files multiple times per month

Infrequently Accessed Data

S3 Standard → S3 Standard-IA
$0.023/GB/month → $0.0125/GB/month (46% cheaper)
Retrieval cost: $0.01/GB
Break-even: < 1 access per month
Use when: Backups, disaster recovery, infrequently accessed files

Unknown Access Patterns

S3 Standard → S3 Intelligent-Tiering
$0.023/GB/month → Automatic optimization
Extra cost: $0.0025 per 1000 objects monitored
Use when: Unclear access patterns, don't want to manage lifecycle
Best for: Mixed workloads, analytics datasets

Archive Storage

S3 Standard → S3 Glacier Instant Retrieval
$0.023/GB → $0.004/GB (83% cheaper)
Retrieval: Milliseconds, $0.03/GB
Use when: Archive with immediate access needs (e.g., medical records)

S3 Standard → S3 Glacier Flexible Retrieval
$0.023/GB → $0.0036/GB (84% cheaper)
Retrieval: Minutes to hours, $0.01/GB
Use when: Archive data, acceptable retrieval delay

S3 Standard → S3 Glacier Deep Archive
$0.023/GB → $0.00099/GB (96% cheaper)
Retrieval: 12 hours, $0.02/GB
Use when: Long-term archive, regulatory compliance, rarely accessed

Decision Tree

Accessed daily → S3 Standard
Accessed monthly → S3 Standard-IA
Unknown pattern → S3 Intelligent-Tiering
Archive, instant access → Glacier Instant Retrieval
Archive, can wait hours → Glacier Flexible Retrieval
Archive, can wait 12 hours → Glacier Deep Archive

EBS Volume Types

General Purpose Volumes

gp2 → gp3
$0.10/GB → $0.08/GB (20% cheaper)
Additional benefits: Configurable IOPS/throughput independent of size
Action: Convert all gp2 to gp3 (no downtime required)

High Performance Workloads

io1 → io2
Same price, better durability and IOPS
io2 Block Express: For highest performance needs

Consider: Do you really need provisioned IOPS?
Many workloads perform fine on gp3 (up to 16,000 IOPS)
Test gp3 before committing to io2

Throughput-Optimized Workloads

gp3 → st1 (Throughput Optimized HDD)
$0.08/GB → $0.045/GB (44% cheaper)
Use when: Big data, data warehouses, log processing
Sequential access patterns, throughput more important than IOPS

Cold Data

gp3 → sc1 (Cold HDD)
$0.08/GB → $0.015/GB (81% cheaper)
Use when: Infrequently accessed data, lowest cost priority
Example: Archive storage, cold backups

EFS vs S3 vs EBS

S3 (Cheapest for Object Storage)

• Cost: $0.023/GB/month (Standard)
• When to use: Object storage, static files, backups
• Pros: Unlimited scale, integrates with everything
• Cons: Not a file system, higher latency

EBS (Best for Single-Instance Block Storage)

• Cost: $0.08/GB/month (gp3)
• When to use: Boot volumes, database storage, single EC2 instance
• Pros: High performance, low latency
• Cons: Single-AZ, attached to one instance

EFS (File System Across Multiple Instances)

• Cost: $0.30/GB/month (Standard), $0.016/GB/month (IA)
• When to use: Shared file storage across multiple instances
• Pros: Multi-AZ, grows automatically, NFSv4
• Cons: More expensive than EBS
• Optimization: Use EFS Intelligent-Tiering to auto-move to IA class

Decision Matrix

Single instance, block storage → EBS
Multiple instances, shared files → EFS (with Intelligent-Tiering)
Object storage, static files → S3
Large data, high throughput → FSx for Lustre
Windows file shares → FSx for Windows

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Database Alternatives

RDS vs Aurora vs Self-Managed

RDS PostgreSQL/MySQL (Baseline)

• Cost: Instance + storage
• When to use: Standard relational DB needs
• Example: db.t3.medium = ~$60/month + storage

Aurora PostgreSQL/MySQL (2-3x RDS Cost)

• Cost: Instance + storage + I/O charges
• When to use: Need high availability, auto-scaling storage, read replicas
• Pros: Better performance, automatic failover, up to 15 read replicas
• Cons: More expensive
• Break-even: High read traffic, need fast replication

Aurora Serverless v2 (Variable Workloads)

• Cost: Pay per ACU (Aurora Capacity Unit) per second
• When to use: Variable load, dev/test, infrequent usage
• Example: Dev database used 8 hours/day → 67% savings vs always-on
• Limitation: Min capacity charges apply

Self-Managed on EC2 (Cheapest for Experts)

• Cost: Just EC2 + EBS costs
• When to use: Full control needed, specific configuration, cost-sensitive
• Pros: Can be 50-70% cheaper than RDS
• Cons: You manage backups, patching, HA, monitoring
• Consideration: Factor in operational overhead

Decision Matrix

Standard workload, managed preferred → RDS
High availability, many reads → Aurora
Variable workload → Aurora Serverless v2
Cost-sensitive, have DBA expertise → Self-managed on EC2
Dev/test, intermittent use → Aurora Serverless v2

DynamoDB Pricing Models

On-Demand (Unpredictable Traffic)

• Cost: $1.25 per million writes, $0.25 per million reads
• When to use: Variable traffic, new applications, spiky workloads
• Pros: No capacity planning, scales automatically
• Example: New API with unknown traffic pattern

Provisioned Capacity (Predictable Traffic)

• Cost: $0.00065 per WCU/hour, $0.00013 per RCU/hour
• When to use: Predictable traffic patterns
• Savings: 60-80% cheaper than on-demand at consistent usage
• Example: Application with steady 100 req/sec

Reserved Capacity (Long-term Commitment)

• Cost: Additional 30-50% discount on provisioned capacity
• When to use: Known long-term capacity needs
• Commitment: 1-3 years

Break-Even Calculation

On-Demand: $1.25 per million writes
Provisioned: ~$0.47 per million writes (at capacity)
Break-even: ~65% consistent utilization

Action: Start with on-demand, switch to provisioned once patterns clear

Database Migration Options

From Commercial to Open Source

Oracle → Aurora PostgreSQL or RDS PostgreSQL
Savings: 90% on licensing costs
Consider: PostgreSQL compatibility, migration effort

SQL Server → Aurora PostgreSQL or RDS PostgreSQL/MySQL
Savings: 50-90% on licensing costs
Consider: Application compatibility, migration effort

From RDS to Aurora

Only if: High availability requirements, many read replicas needed
Cost increase: 20-50% more
Benefit: Better performance, automatic failover, scaling

From Aurora to RDS

When: Don't need Aurora features, cost-conscious
Savings: 20-50%
Downgrade if: Single-AZ sufficient, limited read replicas needed

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Networking Alternatives

NAT Gateway Alternatives

NAT Gateway (Default, Expensive)

• Cost: $32.85/month + $0.045/GB processed
• When to use: Production, high availability, easy management

VPC Endpoints (Cheaper for AWS Services)

• Gateway Endpoint (S3, DynamoDB): FREE
• Interface Endpoint: $7.20/month + $0.01/GB
• When to use: Accessing S3, DynamoDB, or other AWS services
• Savings: $25-30/month vs NAT Gateway
• Example: Lambda accessing S3 → Use S3 Gateway Endpoint

NAT Instance (Cheapest, More Work)

• Cost: Just EC2 cost (e.g., t3.micro = $7.50/month)
• When to use: Dev/test, cost-sensitive, low traffic
• Cons: Must manage, less resilient, manual HA setup
• Savings: 75% vs NAT Gateway

Decision Matrix

S3 or DynamoDB only → Gateway Endpoint (FREE)
Other AWS services → Interface Endpoint
Production, high availability → NAT Gateway
Dev/test, low traffic → NAT Instance or single NAT Gateway

Load Balancer Alternatives

Application Load Balancer (ALB)

• Cost: $16.20/month + LCU charges
• When to use: HTTP/HTTPS, path-based routing, microservices
• Features: Layer 7, content-based routing, Lambda targets

Network Load Balancer (NLB)

• Cost: $22.35/month + LCU charges
• When to use: TCP/UDP, extreme performance, static IPs
• Use case: Non-HTTP protocols, high throughput

Classic Load Balancer (Legacy)

• Cost: $18/month + data charges
• Recommendation: Migrate to ALB or NLB (better features, often cheaper)

CloudFront + S3 (Static Content)

• Cost: Much cheaper for static content
• When to use: Static website, single-page app
• Setup: S3 static hosting + CloudFront distribution
• Savings: 90% vs ALB for static content

API Gateway (REST APIs)

• Cost: Pay per request
• When to use: REST API, need API management features
• Alternative to: ALB for simple APIs

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Application Services

Message Queue Alternatives

SQS vs SNS vs EventBridge vs Kinesis

SQS (Point-to-Point, Cheapest)

• Cost: $0.40 per million requests (Standard), $0.50 (FIFO)
• When to use: Work queues, decoupling services
• Best for: Job processing, task queues

SNS (Pub/Sub, Cheap)

• Cost: $0.50 per million publishes
• When to use: Fan-out notifications, multiple subscribers
• Best for: Notifications, multiple consumers

EventBridge (Event Router)

• Cost: $1.00 per million events
• When to use: Event-driven architecture, complex routing
• Best for: Cross-account events, SaaS integrations

Kinesis (Streaming, Expensive)

• Cost: $0.015 per shard-hour + PUT charges
• When to use: Real-time streaming, ordered processing
• Best for: Logs, analytics, real-time processing
• Alternative: Kinesis Data Firehose (simpler, cheaper for basic needs)

Decision Matrix

Simple queue → SQS
Multiple consumers → SNS
Complex event routing → EventBridge
Real-time streaming → Kinesis
Log aggregation → Kinesis Firehose

Container Orchestration

ECS vs EKS vs Fargate

ECS on EC2 (Cheapest)

• Cost: Just EC2 costs (no ECS fee)
• When to use: AWS-native, simpler workloads
• Best for: Cost-sensitive, AWS-specific deployments

ECS on Fargate (Serverless, Easy)

• Cost: Pay per task (vCPU + memory)
• When to use: Variable load, don't want to manage servers
• Best for: Variable workloads, simpler operations

EKS (Kubernetes, Expensive)

• Cost: $73/month per cluster + node costs
• When to use: Need Kubernetes, multi-cloud, complex deployments
• Best for: Kubernetes expertise, need K8s ecosystem
• Tip: Consolidate workloads to fewer clusters

Decision Matrix

AWS-native, cost-sensitive → ECS on EC2
Variable load, easy management → ECS on Fargate
Need Kubernetes → EKS
Multiple environments → Consider single EKS cluster with namespaces

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Quick Reference: When to Switch

Immediate Actions (Low Risk)

• gp2 → gp3 (20% savings, no downtime)
• S3 Standard → Intelligent-Tiering (auto-optimization)
• NAT Gateway → VPC Endpoints for S3/DynamoDB (free)
• Old generation instances → New generation (10-20% savings)
• Intel → Graviton (20% savings, test first)

Medium Effort Actions

• On-Demand → Reserved Instances/Savings Plans (40-65% savings)
• Always-on EC2 → Lambda for intermittent work
• S3 Standard → Lifecycle policies (50-95% savings on old data)
• RDS On-Demand → Reserved Instances (40-65% savings)
• DynamoDB On-Demand → Provisioned (60-80% savings if predictable)

High Effort Actions (Evaluate Carefully)

• RDS → Aurora (usually more expensive, only if need features)
• Aurora → RDS (20-50% savings if don't need Aurora features)
• Commercial DB → PostgreSQL (90% savings, migration effort)
• EC2 → Lambda (case-by-case, break-even analysis needed)
• ECS → EKS (usually more expensive, only if need K8s)

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Cost Comparison Tool

Use this mental model when evaluating alternatives:

1. Calculate current monthly cost
2. Calculate alternative monthly cost
3. Estimate migration effort (hours × $cost)
4. Calculate payback period: Migration Cost / Monthly Savings
5. Decide: Payback < 3 months → Likely worth it
           Payback > 6 months → Evaluate carefully

Example:

Current: ALB for static site = $20/month
Alternative: CloudFront + S3 = $2/month
Savings: $18/month
Migration: 4 hours × $100/hour = $400
Payback: $400 / $18 = 22 months → Maybe not worth it

But if: Multiple sites, reusable pattern → Worth the investment