Edge Container Orchestration Using Podman and Systemd in Industrial Networks

The Challenge of Edge Computing in Industrial Networks

Modern industrial automation increasingly relies on processing close to machines, a concept known as edge computing. In practice, this means placing small computers directly on the factory floor to read sensors, process quality data, and make split-second decisions without relying on cloud servers. However, these environments impose severe barriers: computers typically have low RAM, modest processors, and often operate under network instability. Bringing packaged modern applications to these locations requires strategies that avoid heavy enterprise solutions, prioritizing simplicity and extreme robustness.

Historically, container technology revolutionized how we package software, grouping the program and all its dependencies into a single isolated package. However, traditional large-scale orchestration tools like Kubernetes were designed for massive data centers and demand significant resources just to keep their basic infrastructure running. On an industrial computer with two gigabytes of RAM, dedicating half the resources solely to managing the container system is unfeasible. We must find a middle ground that offers container isolation without the operational weight of large platforms.

Why Replace the Traditional Daemon with Podman

Podman emerges as a direct and elegant alternative for resource-constrained scenarios by eliminating the need for a daemon, which is that central background program responsible for managing all containers. In traditional architecture, if this central process fails, the entire container system is compromised. Podman interacts directly with the Linux operating system kernel to create and isolate processes, operating in a fully decentralized manner. In practice, each container runs as a regular operating system process, which facilitates monitoring and drastically reduces memory and processing consumption on the edge machine.

Another significant gain of Podman in industrial environments is enhanced security by default. Since it does not require superuser privileges to run most operations, applications compromised by security flaws do not gain unrestricted access to the rest of the factory hardware. Furthermore, command compatibility with legacy tools facilitates the transition for teams already using other ecosystems. The learning curve becomes smaller, allowing automation engineers and field technicians to deploy software updates with the same level of confidence they handle local scripts.

Integrating the Container Lifecycle with Systemd

To ensure an industrial application runs uninterrupted, it must restart on its own if a power outage or software failure occurs. This is precisely where Systemd comes in, the default initialization and service manager for the vast majority of modern Linux distributions. Instead of introducing an external orchestration tool, we can turn our Podman-managed containers into native Systemd services. In practice, this means the operating system views the container exactly like a traditional database or a local web server, automatically controlling its health.

The integration process is based on creating simple configuration files known as service units. Podman itself has a built-in command that reads a container or a composition file and automatically generates the script needed for Systemd. Below, we exemplify how to structure a service file to keep an industrial application running at all times:

[Unit]
Description=Industrial Modbus Gateway Service
After=network.target network-online.target
Wants=network-online.target

[Service]
Type=simple
Restart=always
RestartSec=10
ExecStart=/usr/bin/podman start -a modbus-gateway
ExecStop=/usr/bin/podman stop -t 10 modbus-gateway

[Install]
WantedBy=multi-user.target

With this file properly positioned in the operating system's service directory, basic commands to enable and start the container are managed by native Linux infrastructure. If the container process crashes due to lack of memory or an internal error, Systemd waits ten seconds and attempts a new startup, guaranteeing the operational resilience demanded by the factory floor without constant human intervention.

Industrial Network Topology and Port Isolation

Factory environments require rigorous network segmentation to separate corporate traffic from field control buses, where protocols like Modbus TCP or OPC UA circulate. In edge nodes using Podman, correct network configuration prevents failures in visualization or metric collection services from compromising direct communication with PLCs (Programmable Logic Controllers). The use of software-defined networks at the Podman level allows creating isolated bridges and restricting traffic strictly to the ports necessary for operation.

In practice, configuring network isolation requires extra attention to port mapping parameters when starting containers. You should avoid exposing database services or administrative panels directly to the factory's general public network interface. Restricting local traffic through firewall rules integrated into the system ensures that only authorized supervisor IP addresses can establish connections with open ports at the edge, mitigating cyber risks in critical infrastructure. To explore these architectural concepts further in production, see our related technical analysis on Edge Device Orchestration with Industrial Protocols and Secure MQTT on Private Cellular Networks.

Final Considerations on Edge Maintainability

The joint adoption of Podman and Systemd in industrial networks demonstrates that it is entirely possible to achieve high availability and refined container control without resorting to complex and heavy architectures. By eliminating the need for centralized daemons and leveraging the native features of the Linux operating system itself, engineers gain predictability, low resource consumption, and ease of remote or local maintenance. This pragmatic approach consolidates edge computing as a viable, stable, and secure reality for industrial plants of any size.