Designing a scalable framework for declarative automation on distributed systems

As distributed systems grow in scale and complexity, the need for flexible automation of systems management functions also grows. We outline a framework for building tools that provide distributed, scalable, declarative, modular, and continuous automation for distributed systems. We focus on four points of design: 1) a state-management approach that prescribes source-of-truth for configured and discovered system states; 2) a technique to solve the declarative unification problem for a class of automation problems, providing state convergence and modularity; 3) an eventual-consistency approach to state synchronization which provides automation at scale; 4) an event-driven architecture that provides always-on state enforcement. We describe the methodology, software architecture for the framework, and constraints for these techniques to apply to an automation problem. We overview a reference application built on this framework that provides state-aware system provisioning and node lifecycle management, highlighting key advantages. We conclude with a discussion of current and future applications.