Apollo Configuration Center

Apollo is a reliable distributed configuration management system for microservice architectures, enabling centralized configuration with real-time push, version control, and environment isolation. Developed by Ctrip (headquartered in Shanghai, China) in 2016 and led by Song Shun Yuan, Apollo is widely adopted by enterprises including Didi, Weibo, and 360. Key features: unified configuration management across multiple environments (dev, fat, uat, pro), clusters, and namespaces, with hierarchical inheritance and override. Real-time configuration push: changes pushed to all instances within 1 second via long-polling HTTP, eliminating restarts. Version management: every change is versioned with full audit trail (who, what, when, why), with rollback to any version. Gray release: phased rollout to a subset of instances for safe testing, with configurable strategies (by IP, by weight). Permission management: RBAC with project, environment, and namespace-level permissions, supporting public and private namespaces. Configuration format: properties, XML, JSON, YAML, text. Client SDK: Java, .NET, Python, Node.js, Go, PHP, C++ with local file caching and automatic retry. Cluster management for multiple data centers. RESTful API for programmatic management. Change notifications via email, DingTalk, WeChat, webhook. High availability: multi-instance with no single point of failure. MySQL for persistence, Eureka for discovery. Open source under Apache-2.0.