Fly.io enables the deployment of containerized applications globally, allowing users to run headless Chrome instances as Firecracker VMs in various locations, such as Singapore, Sydney, Paris, and Chile, for tasks like web page loading and testing. The deployment process involves using tools like Docker and Fly's CLI to set up applications and secure them via WireGuard for private network communications. For service discovery and cluster management, HashiCorp's Serf is utilized, offering a simpler alternative to Consul by providing a decentralized system that manages cluster membership and health checks using the SWIM protocol. Serf also incorporates the Vivaldi algorithm to map network distances between nodes, enabling efficient service discovery without relying on DNS. This setup allows for scalable and secure management of distributed systems, providing a practical introduction to real-world implementation of these technologies on Fly.io's platform.