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Tuần 7 - Ngày 1: High Availability Architectures

Tuần 7 – Ngày 1

Tuần 7 - Ngày 1: High Availability Architectures

1. HA Design Principles

┌─────────────────────────────────────────────────────────┐│HAPRINCIPLES││││1.EliminateSinglePointsofFailure││-Multi-AZdeployments││-Redundantcomponents││││2.DesignforFailure││-Assumecomponentswillfail││-Implementhealthchecks││-Auto-healingmechanisms││││3.LooseCoupling││-Usequeuesbetweencomponents││-Asyncwherepossible││││4.StatelessApplications││-Storestateexternally││-Easyhorizontalscaling│└─────────────────────────────────────────────────────────┘

2. Multi-AZ Architecture

┌─────────────────────────────────────────────────────────┐│MULTI-AZWEBAPP││││┌───────────────┐│││Route53││││(DNS)│││└───────┬───────┘│││││┌───────┴───────┐│││ALB││││(Multi-AZ)│││└───────┬───────┘│││││┌───────────────┼───────────────┐││▼▼▼││┌──────────┐┌──────────┐┌──────────┐│││AZ-a││AZ-b││AZ-c││││┌──────┐││┌──────┐││┌──────┐│││││EC2││││EC2││││EC2│││││└──────┘││└──────┘││└──────┘│││└──────────┘└──────────┘└──────────┘│││││┌───────┴───────┐│││RDSMulti-AZ││││orAurora│││└───────────────┘│└─────────────────────────────────────────────────────────┘

3. Auto Scaling Strategies

SCALING POLICIES:

1. Target Tracking (Recommended)
   - Maintain CPU at 50%
   - Simple configuration

2. Step Scaling
   - Multiple thresholds
   - Different actions per step

3. Scheduled Scaling
   - Known traffic patterns
   - Time-based

4. Predictive Scaling
   - ML-based prediction
   - Proactive scaling

COOLDOWN PERIODS:
- Default: 300 seconds
- Prevents rapid scale in/out
- Can customize per policy

4. Session Management

STATELESSPATTERN:┌─────────────────────────────────────────────────────────┐│User──►ALB──►AnyEC2instance│││││▼││┌─────────────────────┐│││ElastiCache(Redis)││││SessionStore│││└─────────────────────┘││││Benefits:││-Instancecanfail││-Scalein/outfreely││-Nostickysessionsneeded│└─────────────────────────────────────────────────────────┘

5. Database HA Patterns

RDS:├──Multi-AZ(syncreplication,autofailover)├──ReadReplicas(async,manualpromotion)└──CombinationofbothAurora:├──6copiesacross3AZs├──Writer+upto15readers├──Autofailover<30seconds└──GlobalDatabaseforcross-regionDynamoDB:├──Multi-AZbydefault└──GlobalTablesformulti-region

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Ngày tiếp theo: Disaster Recovery Strategies