arXiv:2610.10544v1 Announce Type: cross Abstract: Integrating legacy industrial machinery into modern cloud infrastructures poses a significant software engineering challenge. Industrial Internet of Things (IIoT) deployments frequently rely on rigid and proprietary edge controllers that require extensive manual configuration. Open-source single-board computers (SBCs) offer a highly adaptable hardware alternative, but they still lack standardized software deployment frameworks capable of bridging localized serial protocols with global cloud environments. In this paper, we present a modular event-driven software architecture designed specifically for open-source IIoT edge gateways. We built a containerized web stack to provide a unified architecture that abstracts the complexities of Modbus-to-MQTT protocol translation, enabling rapid configuration of telemetry streams to cloud platforms such as Amazon Web Services (AWS) IoT. Furthermore, we designed a localized event engine that processes conditional logic directly at the edge layer, which significantly reducing network latency. The proposed architecture is preliminarily deployed and validated on an industrial-grade Raspberry Pi Compute Module 4 (CM4) to investigate its robustness, scalability and user-friendliness. Experimental results demonstrate a substantial reduction in system integration time and high operational stability, thus establishing a robust software foundation for real-time edge-based industrial automation. This paper contributes to extending the lifespan of legacy machinery by enabling seamless integration with modern industrial infrastructure.