Gracefully putting a service into maintenance without nginx configuration (Part 1) - Kurly Tech Blog

Kolly’s engineering team built AccessBlock to block user actions during maintenance when nginx-based blocking wasn’t available.

The first version used MySQL tables and frontend route checks to redirect users to a maintenance page.

They later moved the blocking state to Redis, reducing reliance on the primary database during outages or heavy maintenance.

The system improves service stability by handling warehouse and database maintenance more safely and flexibly.