Real-Time Performance Evaluation of Containerized Virtual PLCs: A Comparative Study of Docker and Podman for Industrial Automation

The integration of Information Technology (IT) and Operational Technology (OT) in modern production systems requires flexible, scalable, and deterministic control systems. Virtual Programmable Logic Controllers (vPLCs), deployed in containerized environments, are gaining traction as a cost-effective and adaptable alternative to traditional hardware PLCs. However, ensuring real-time performance in virtualized environments remains a critical challenge, especially under varying system loads and resource constraints. This paper presents a comparative evaluation of two vPLC platforms, CODESYS Control and OpenPLC, running within Docker and Podman containers on a Linux system with the PREEMPT-RT real-time kernel. The analysis covers both default and real-time-optimized configurations, focusing on timing precision, jitter, and deadline violations under increasing computational workloads. Experimental results reveal that Podman offers more predictable and stable real-time behavior than Docker, particularly in untuned scenarios. These findings emphasize the importance of running-time selection and system-level tuning to achieve deterministic execution for industrial automation. ... mehrThe results provide practical guidance for the deployment of containerized control workloads on the industrial edge and contribute to the broader goal of reliable hardware-agnostic systems in time-sensitive environments.