System Design of Hotel Booking Applications: Microservices Architecture, Databases, and Messaging

Hotel Management Service

The hotel management service provides a portal for hotel owners or managers to create and update hotel information. Requests from the management app are routed through a load balancer to a cluster of service containers, which interact with a master‑slave database cluster (writes to the master, reads from the slave). Updates are propagated to a CDN and message‑queue systems such as Kafka or RabbitMQ for further processing.

Customer Service (Search + Booking)

This service is exposed to end‑users for searching and booking hotels. The client app calls APIs that pass through a load balancer to the appropriate micro‑service. Search queries retrieve data from Elasticsearch, while the booking service interacts with Redis for caching and a booking database cluster for persistence. The booking service also communicates with third‑party payment providers.

All changes to the database are sent to the message queue; a consumer reads the events and stores them in Cassandra for long‑term archival, as Cassandra handles large data volumes efficiently.

View Booking Service

This service displays current and historical bookings to both customers and managers. Requests go through the load balancer to the booking management servers, which fetch recent data from Redis (cache) and historical data from Cassandra, reducing latency and load on the primary databases.

Final Design

The complete architecture includes a Kafka consumer that sends notifications to customers or managers (e.g., new bookings or promotions). An Apache Streaming service pulls data from the message queue into Hadoop for big‑data analytics such as business analysis, lead generation, and audience segmentation.