Disaster recovery and high availability design in Serverless architecture need to consider redundancy mechanisms provided by cloud providers and business continuity requirements:
High availability architecture design:
1. Multi-AZ deployment
- Automatic redundancy: Cloud providers automatically deploy function instances across multiple availability zones
- Failover: Automatic switch when a single availability zone fails
- Data redundancy: Use multi-AZ databases and storage services
2. Load balancing
- API Gateway: Automatically distribute traffic to multiple function instances
- CDN acceleration: Use CloudFront to distribute global traffic
- Health checks: Automatically detect and remove unhealthy instances
3. Auto-scaling
- Elastic scaling: Automatically scale function instances based on traffic
- Reserved concurrency: Reserve concurrency instances for critical functions
- Rate limiting: Prevent service unavailability due to traffic overload
Disaster recovery strategies:
1. Data backup
- Automatic backup: Enable automatic database backup
- Cross-region replication: Replicate data to different regions
- Version control: Use S3 version control to protect data
2. Failover
- Multi-region deployment: Deploy applications in multiple regions
- DNS switching: Use Route53 for failover
- Blue-green deployment: Keep two versions running simultaneously
3. Recovery plan
- RPO/RTO: Define Recovery Point Objective and Recovery Time Objective
- Drill testing: Regularly conduct disaster recovery drills
- Documentation: Document recovery processes and contacts in detail
Monitoring and alerting:
1. Health monitoring
- Service availability: Monitor service availability
- Performance metrics: Monitor response time, error rate and other metrics
- Resource usage: Monitor CPU, memory, storage usage
2. Alerting mechanisms
- Multi-level alerts: Set different levels of alerts
- Multi-channel notifications: Send alerts via email, SMS, Slack, etc.
- Automatic response: Trigger automatic recovery processes
Best practices:
- Minimize dependencies: Reduce dependence on single services
- Idempotent design: Ensure operations can be safely retried
- Degradation strategies: Implement service degradation to ensure core functions
- Regular drills: Regularly conduct disaster recovery drills
Candidates should be able to share high availability and disaster recovery experience from actual projects.