On building scalable control planes
The article discusses the challenges and design decisions behind building scalable control planes, specifically through the author's experience working on EC2 and DSQL at AWS. The control plane, responsible for reconciling what should be true and what actually is, plays a crucial role in maintaining the stability and scalability of cloud services. The author emphasizes the importance of static stability, ensuring that running VMs continue to function uninterrupted. In EC2's control plane, this is achieved by maintaining a relational database that reflects the state of the service, allowing for rapid identification and correction of discrepancies. To achieve scalability, the control plane must continuously monitor and adapt to changes in the underlying infrastructure, while maintaining consistency and avoiding single points of failure. The author highlights the trade-offs inherent in designing control planes, weighing the need for static stability against the risk of system failures and disruptions. By sharing lessons learned from his experience, the author aims to provide insights for engineers working on control planes, emphasizing the importance of careful design, scalability, and res