PM2 is a process manager for Node.js applications that offers the ability to keep applications online, monitor performance, and manage environment variables, making it a viable alternative to Docker. The guide details how to set up the automation tool n8n using PM2, including step-by-step instructions for installation, configuration, and management on both Linux and Windows systems. It highlights the benefits of auto-restarting applications after updates or system reboots, configuring environment variables, and setting up Nginx with SSL for secure access. While n8n can be self-hosted for free under a fair-code license, the guide notes that Docker is the officially supported method for running n8n. Additionally, n8n users are encouraged to explore advanced configurations and domain customization to enhance their automation workflows.