Getting Started

This section describes how to install the CernVM-FS client. The CernVM-FS client is supported on x86, x86_64, and ARM architectures running Linux or Mac OS X \(\geq 10.12\). There is experimental support for Power 8 and RISC-V.


The CernVM-FS repositories are located under /cvmfs. Each repository is identified by a fully qualified repository name. On Linux, mounting and un-mounting of the CernVM-FS is usually controlled by autofs and automount. That means that starting from the base directory /cvmfs different repositories are mounted automatically just by accessing them. A repository will be automatically unmounted after some automount-defined idle time. On macOS, mounting and un-mounting of the CernVM-FS is done by the user with sudo mount -t cvmfs /cvmfs/... commands.

Getting the Software

The CernVM-FS source code and binary packages are available from the CernVM website. However it is recommended to use the available package repositories that are also provided for the supported operating systems.

Scientific Linux/CentOS

To add the CVMFS repository and install CVMFS run

sudo yum install
sudo yum install -y cvmfs


To add the CVMFS repository and install CVMFS run

sudo dpkg -i cvmfs-release-latest_all.deb
rm -f cvmfs-release-latest_all.deb
sudo apt-get update
sudo apt-get install cvmfs


To install the CVMFS package run

sudo dnf install

Mac OS X

Install the CernVM-FS package by opening the .pkg file.

Seting up the Software

Configure AutoFS

For the basic setup, run cvmfs_config setup. This ensures that /cvmfs /etc/auto.cvmfs is set in /etc/auto.master and that the autofs service is running. Reload the autofs service in order to apply an updated configuration.

Mac OS X

On Mac OS X, CernVM-FS is based on OSXFuse. It is not integrated with autofs hence mount the individual repositories using

sudo mkdir -p /cvmfs/
sudo mount -t cvmfs /cvmfs/

Create default.local

Create /etc/cvmfs/default.local and open the file for editing. Select the desired repositories by setting CVMFS_REPOSITORIES=repo1,repo2,.... For ATLAS, for instance, set,,

Specify the HTTP proxy servers on your site with


If you’re unsure about the proxy names, set CVMFS_HTTP_PROXY=DIRECT. This should only be done for a small number of clients (< 5), because large numbers can put a heavy load on the Stratum 1 servers and result, amongst others, in poorer performance for the client. For the syntax of more complex HTTP proxy settings, see Network Settings.

Verify the file system

Check if CernVM-FS mounts the specified repositories by cvmfs_config probe. If the probe fails, try to restart autofs with sudo systemctl restart autofs.

Building From Source

The CernVM-FS client is not relocatable and needs to be installed under /usr. On Intel architectures, it needs a gcc \(\geq 4.2\) compiler, on ARMv7 a gcc \(\geq 4.7\) compiler. In order to compile and install from sources, use the following commands

cd <source directory>
mkdir build && cd build
cmake ../
sudo make install


In order to check for common misconfigurations in the base setup, run

cvmfs_config chksetup

CernVM-FS gathers its configuration parameter from various configuration files that can overwrite each others settings (default configuration, domain specific configuration, local setup, …). To show the effective configuration for, run:

cvmfs_config showconfig

In order to exclude autofs/automounter as a source of problems, you can try to mount manually with the following

mkdir -p /mnt/cvmfs
mount -t cvmfs /mnt/cvmfs

In order to exclude SELinux as a source of problems, you can try mounting after SELinux has been disabled by

/usr/sbin/setenforce 0

Once the issue has been identified, ensure that the changes are taken by restarting autofs

systemctl restart autofs