Tera-architectures are extremely large-scale computing systems that self-assemble from components and implement resilience through a software architecture designed to detect, tolerate and automatically respond to component failure. Due to the scale (tens or hundreds of thousands of servers running the application), components are constantly breaking, and failures happen often, but the resilient design allows the service to be successfully delivered to users, despite the hidden internal failures. Software has to change or be written specifically to operate in such an environment.