Leader: Valentin Volkl
🌐 cernvm.cern.ch 💻 github.com/cernvm 📅 meetings

The CernVM Appliance

CernVM is a Virtual Software Appliance for the CERN LHC experiments. The appliance represents a complete, portable and easy to configure user environment for developing and running LHC data analysis tasks locally and on institutional and commercial clouds (OpenStack, Amazon EC2, Google Compute Engine), independently of operating system software and hardware platform (Linux, Windows, MacOS).

The goal is to remove a need for the installation of the experiment software and to minimize the number of platforms (compiler-OS combinations) on which experiment software needs to be supported and tested.

CernVM-FS

The CernVM File System provides a scalable, reliable and low-maintenance software distribution service. It was developed to assist High Energy Physics (HEP) collaborations to deploy software on the worldwide-distributed computing infrastructure used to run data processing applications. CernVM-FS is implemented as a POSIX read-only file system in user space (a FUSE module). Files and directories are hosted on standard web servers and mounted in the universal namespace /cvmfs.

Internally, CernVM-FS uses content-addressable storage and Merkle trees in order to store file data and meta-data. CernVM-FS uses outgoing HTTP connections only, thereby it avoids most of the firewall issues of other network file systems. It transfers data and meta-data on demand and verifies data integrity by cryptographic hashes.