Distributed filesystem layer
For the distribution of the software stack we are using the CernVM File System, the CernVM File System provides a scalable, reliable and low-maintenance software distribution service
The CernVM File System (CernVM-FS) is a read-only file system designed to deliver scientific software onto virtual machines and physical worker nodes in a fast, scalable, and reliable way. Files and file metadata are downloaded on demand and aggressively cached. For the distribution of files, CernVM-FS uses a standard HTTP transport, which allows exploitation of a variety of web caches, including commercial content delivery networks. CernVM-FS ensures data authenticity and integrity over these possibly untrusted caches and connections. The CernVM-FS software comprises client-side software to mount “CernVM-FS repositories” as well as a server-side toolkit to create such distributable CernVM-FS repositories.
CernVM-FS is a web-based, global, and versioning file system optimized for software distribution. The file system content is installed on a central web server from where it can be mirrored and cached by other web servers and web proxies. File system clients download data and meta-data on demand and cache them locally. Data integrity and authenticity is ensured by cryptographic hashes and digital signatures.
Detailed information about how we configure CVMFS is available at https://github.com/EESSI/filesystem-layer .