Design the system to be fault-tolerant and resilient to failures

Designing a fault-tolerant and resilient flight ticket booking system involves implementing mechanisms to handle errors, recover from failures, and maintain system availability even in the face of unexpected issues. Here are some key strategies and mechanisms to achieve fault tolerance and resilience:

Redundancy and Replication:

• Use redundant components such as load balancers, web servers, and database servers to ensure high availability.
• Implement database replication (e.g., master-slave or master-master replication) to maintain a synchronized copy of data across multiple nodes.

Automated Failover:

• Implement automated failover mechanisms to switch to backup components or nodes in case of a failure.
• Use health checks and monitoring to detect failures and trigger failover processes automatically.

Graceful Degradation while Designing fault-tolerant and resilient system:

• Design the system to gracefully degrade functionality under high load or in the event of component failures.
• Identify critical and non-critical functionalities and prioritize them accordingly during periods of high demand or resource constraints.

Learn more about the challenges faced with external APIs “Expected Challenges while designing flight booking system with external APIs“

Circuit Breaker Pattern:

• Implement the circuit breaker pattern to prevent cascading failures by temporarily halting requests to a failing service.
• Use configurable thresholds for error rates and response times to open and close the circuit breaker.

Retry and Backoff Strategies:

• Implement retry and backoff strategies for handling transient errors such as network timeouts or service unavailability.
• Use exponential backoff to gradually increase the interval between retries to avoid overwhelming the system.

Distributed Tracing and Monitoring While Designing fault-tolerant and resilient System:

• Use distributed tracing tools to monitor the flow of requests across services and identify bottlenecks or failures in the system.
• Monitor system metrics such as CPU usage, memory utilization, and network latency to detect anomalies and performance issues.

Isolation and Containment:

• Design the system with isolation in mind to contain failures and prevent them from affecting other parts of the system.
• Use techniques such as containerization (e.g., Docker) and microservices architecture to isolate components and limit the blast radius of failures.

Rolling Updates and Blue-Green Deployments:

• Implement rolling updates and blue-green deployments to minimize downtime and mitigate the impact of updates or changes to the system.
• Gradually deploy updates to a subset of nodes while keeping the rest of the system operational, allowing for seamless transitions.

Disaster Recovery Planning:

• Develop a disaster recovery plan to handle catastrophic failures or outages that affect the entire system or data center.
• Implement off-site backups, data replication across geographically distributed regions, and failover to secondary data centers if necessary.

By incorporating these strategies and mechanisms into the design of the flight ticket booking system, you can create a resilient and fault-tolerant architecture that can withstand failures, recover gracefully, and maintain high availability for users.