Classic Solution Architectures

info

These were the topics I created flashcards for (Remnote) and would revise them using spaced repetition. The formatting is an export from Remnote.

WhatsTheTime.com - WELL ARCHITECTED FRAMEWORK (stateless) #Stateless
MyClothes.com - 3-TIER WEB ARCHITECTURE (stateless)
- Problem case: managing customer and data as stateless as possible. #Stateless
- Solutions Applied
```
1. Session Affinity i.e. "sticky sessions" or Cookies
2. "Cookies" (stateless)
3. "Server Session" - store session data to DB (Cache)
4. "Store User Data" - store user data to DB
5. "Scale Reads" OR "Cache Write-through"
6. "Survive Disaster" use Multi-AZ
7. "Ensure Security" use Security Groups restrict what can talk to what.
```
- Questions about this architecture
  - The three tiers
    - Web Tier
      - ELB - can do stick sessions, "duration-based" and "application-based"
      - Web clients - can store session "Cookies"
    - Application Tier
      - EC2 ‒ nothing special here.
    - Database Tier
      - Elasticache ‒ session data, DB cache, Multi-AZ capable.
      - RDS ‒ user data, Read Replicas to scale, Multi-AZ (DR)
  - Security Groups
MyWordPress.com STATEFUL WEB APP SCALABLE
- Aurora Database
  - Multi-AZ for DR
  - Read Replicas for scale
- Data in EBS (single)
  - fast but tightly-coupled
- Data in EFS (distributed)
  - distributed decoupled
Init Apps Quickly
- Golden AMI
- Userdata Scripts
- Hybrid
  - Golden AMI
  - Userdata Scripts
Beanstalk - get developers up & running quickly + fully featured, autoscaling, health checks