How systemd turned a routine restart script into an infinite deadlock

The author analyzes a critical infrastructure issue caused by the interaction between systemd and routine automation scripts. A standard setup, where a script generates a configuration and restarts a service, resulted in an infinite deadlock between units. Due to default timeout settings and a lack of self-monitoring for the data collection system, the issue went unnoticed for several weeks. The article details the failure mechanics, referencing systemd documentation, and provides diagnostic methods for similar scenarios. The key takeaway emphasizes the need for rigorous monitoring of infrastructure tools and a deeper understanding of system service manager behavior. The article includes 'before/after' diagrams and a set of commands to check existing configurations for similar vulnerabilities, highlighting the importance of reliability even in the simplest automated processes.