Managing Thousands of API/Batch Servers with a Single Configuration System

A single small typo in a configuration file can lead to serious infrastructure failures, such as settlement errors worth billions of won. Especially in environments operating thousands of API and Batch servers, configuration duplication is a major cause of bugs and outages.

To address this, we introduced an Overlay Architecture. Configuration values are managed in layers such as global, cluster, phase, and application, designed so that lower layers have higher priority, thereby preventing duplication.

We also applied a Template Pattern to solve the problem of difficulty modifying only specific values within long strings. By using variables like {{MAX_HEAP}} to fill in values within configuration settings, we secured flexibility in configuration and minimized the risk caused by typos.