Microsoft Certified: DevOps Engineer ExpertImplement a Site Reliability Engineering (SRE) strategyHard
A financial services company uses Azure Kubernetes Service (AKS) for its core banking application. They need a disaster recovery strategy that provides a relatively fast recovery time (RTO of 2-4 hours) and ensures data consistency, but they want to keep costs lower than a full active-active deployment. They are willing to accept a brief period of reduced capacity during recovery. Which DR strategy is most appropriate?
- AHot Standby (Active-Active)
- BWarm Standby
- CBackup and Restore
- DPilot Light
Show answer & explanationAnswer & explanation
Correct answer: D. Pilot Light
Pilot Light is the most appropriate strategy. It involves deploying a minimal, pre-configured infrastructure (the 'pilot light') in a secondary region with data continuously replicated. When a disaster occurs, the compute resources are provisioned and scaled up, allowing for an RTO of 2-4 hours. This is more cost-effective than Warm Standby or Hot Standby while being faster than Backup and Restore.
Why the other options are wrong
- A. Hot Standby (Active-Active) provides near-zero RTO but is the most expensive option, directly conflicting with the goal of keeping costs lower.
- B. Warm Standby maintains a scaled-down but running environment, which would be faster than Pilot Light but also more expensive, exceeding the 'lower cost' objective for a 2-4 hour RTO.
- C. Backup and Restore typically has a much higher RTO (many hours to days) and RPO (hours to days), making it unsuitable for a 2-4 hour RTO.
Pilot Light DR Strategy
A disaster recovery strategy where a minimal, critical set of resources and continuously replicated data are maintained in a secondary region, ready to be fully provisioned and scaled up upon disaster.
- Balances cost and RTO/RPO.
- Core infrastructure always running, compute provisioned on demand.
- Faster recovery than Backup & Restore, slower than Warm/Hot Standby.
Memory trick: Pilot Light keeps the engine warm, ready for takeoff, but not full speed.