Software Release Build Process and Components in ATLAS Offline.

ATLAS is one of the largest collaborations in the physical sciences. The collaboration involves 3000 scientists and engineers from 174 institutions in 38 countries. This geographically dispersed developer community produces a huge amount of software. The ATLAS Offline software code is organized in 10 projects and in this presentation we discuss how the software is built on variety of compiler and operating system combinations every night. File level parallelism and package level parallelism together with multi-core build servers are used to perform fast builds of the different platforms in several branches. We discuss the different tools involved during the software release build process and also the various mechanisms implemented to provide performance gains and error detection and retry mechanisms in order to counteract network and other instabilities that would otherwise degrade the robustness of the system. We provide to our developers and user quality software built as fast as possible ready for tests and production.