From Kubernetes to Knactor: A State-Centric Rethink of Service Integration

Microservices are increasingly used in modern applications, leading to a growing need for effective service integration solutions. However, we argue that traditional API-centric integration mechanisms (e.g., RPC, REST, and Pub/Sub) hamper the modularity of microservices. These mechanisms introduce rigid code-level coupling, scatter integration logic, and hinder visibility into cross-service state exchanges. Ultimately, these limitations complicate the maintenance and evolution of microservice-based applications. In response, we propose a rethinking of service integration and present Knactor, a new state-centric integration framework to restore the modularity that microservices were intended to offer. Knactor decouples service integration from service development, allowing integration to be implemented as explicit state exchanges among multiple services. Our initial case study suggests that Knactor simplifies service integration and creates new opportunities for optimizations.