Getting Access to EESSI¶

To get access to EESSI, it suffices to have CernVM-FS installed, and make it aware of the EESSI repository.

Is EESSI accessible?¶

EESSI can be accessed via a native (CernVM-FS) installation, or via a container that includes CernVM-FS.

Before you look into these options, check if EESSI is already accessible on your system.

Run the following command:

ls /cvmfs/software.eessi.io

If you see output like shown below, you already have access to EESSI on your system.

README.eessi  defaults  host_injections  init  versions

For starting to use EESSI, continue reading about Setting up environment.

If you see an error message as shown below, EESSI is not yet accessible on your system.

ls: /cvmfs/software.eessi.io: No such file or directory

Continue reading about the Native installation of EESSI, or accessing EESSI via a container.

Native installation¶

Setting up native access to EESSI, that is a system-wide deployment that does not require workarounds like using a container, requires the installation and configuration of CernVM-FS.

This requires admin privileges, since you need to install CernVM-FS as an OS package.

The following actions must be taken for a (basic) native installation of EESSI:

• Installing CernVM-FS itself, ideally using the OS packages provided by the CernVM-FS project (although installing from source is also possible);
• Installing the EESSI configuration for CernVM-FS, which can be done by installing the cvmfs-config-eessi package that we provide for the most popular Linux distributions (more information available here);
• Creating a small client configuration file for CernVM-FS (/etc/cvmfs/default.local); see also the CernVM-FS documentation.

The good news is that all of this only requires a handful commands :

# Installation commands for RHEL-based distros like CentOS, Rocky Linux, Almalinux, Fedora, ...

# install CernVM-FS
sudo yum install -y https://cvmrepo.s3.cern.ch/cvmrepo/yum/cvmfs-release-latest.noarch.rpm
sudo yum install -y cvmfs

# create client configuration file for CernVM-FS (no squid proxy, 10GB local CernVM-FS client cache)
sudo bash -c "echo 'CVMFS_CLIENT_PROFILE="single"' > /etc/cvmfs/default.local"
sudo bash -c "echo 'CVMFS_QUOTA_LIMIT=10000' >> /etc/cvmfs/default.local"
sudo bash -c "echo 'CVMFS_USE_CDN=yes' >> /etc/cvmfs/default.local"

# make sure that EESSI CernVM-FS repository is accessible
sudo cvmfs_config setup

# Installation commands for Debian-based distros like Ubuntu, ...

# install CernVM-FS
sudo apt-get update
sudo apt-get install -y lsb-release wget
wget https://cvmrepo.s3.cern.ch/cvmrepo/apt/cvmfs-release-latest_all.deb
sudo dpkg -i cvmfs-release-latest_all.deb
rm -f cvmfs-release-latest_all.deb
sudo apt-get update
sudo apt-get install -y cvmfs

# create client configuration file for CernVM-FS (no squid proxy, 10GB local CernVM-FS client cache)
sudo bash -c "echo 'CVMFS_CLIENT_PROFILE=single' > /etc/cvmfs/default.local"
sudo bash -c "echo 'CVMFS_QUOTA_LIMIT=10000' >> /etc/cvmfs/default.local"
sudo bash -c "echo 'CVMFS_USE_CDN=yes' >> /etc/cvmfs/default.local"

# make sure that EESSI CernVM-FS repository is accessible
sudo cvmfs_config setup

EESSI via a container¶

A small script can provide a very easy yet versatile means to access EESSI using a container.

#!/bin/bash

# honor $TMPDIR if it is already defined, use /tmp otherwise
if [ -z $TMPDIR ]; then
    export WORKDIR=/tmp/$USER
else
    export WORKDIR=$TMPDIR/$USER
fi

# Make directories required by CVMFS and mount bind them to the right locations
mkdir -p ${WORKDIR}/{var-lib-cvmfs,var-run-cvmfs}
export SINGULARITY_BIND="${WORKDIR}/var-run-cvmfs:/var/run/cvmfs,${WORKDIR}/var-lib-cvmfs:/var/lib/cvmfs"

# Use a temporary home directory since we want a playground
mkdir -p ${WORKDIR}/home
export SINGULARITY_HOME="${WORKDIR}/home:/home/$USER"

# Tell apptainer to fusemount EESSI using CVMFS
export EESSI_REPO="container:cvmfs2 software.eessi.io /cvmfs/software.eessi.io"

# Start a shell
singularity shell --fusemount "$EESSI_REPO" docker://ghcr.io/eessi/client:rocky8

This page guides you through an example scenario illustrating the use of the script.

Quickstart¶

Run the eessi_via_container.sh script to start a shell session in the container with EESSI available:

./eessi_via_container.sh

You should see output like

INFO:    Environment variable SINGULARITY_BIND is set, but APPTAINER_BIND is preferred
INFO:    Environment variable SINGULARITY_HOME is set, but APPTAINER_HOME is preferred
INFO:    Converting OCI blobs to SIF format
INFO:    Starting build...
INFO:    Fetching OCI image...
161.9KiB / 161.9KiB [===============================================================================] 100 % 3.1 MiB/s 0s
41.2MiB / 41.2MiB [=================================================================================] 100 % 3.1 MiB/s 0s
5.2MiB / 5.2MiB [===================================================================================] 100 % 3.1 MiB/s 0s
68.8MiB / 68.8MiB [=================================================================================] 100 % 3.1 MiB/s 0s
117.8MiB / 117.8MiB [===============================================================================] 100 % 3.1 MiB/s 0s
88.4MiB / 88.4MiB [=================================================================================] 100 % 3.1 MiB/s 0s
INFO:    Extracting OCI image...
2026/05/31 08:50:54  warn rootless{usr/libexec/openssh/ssh-keysign} ignoring (usually) harmless EPERM on setxattr "user.rootlesscontainers"
INFO:    Inserting Apptainer configuration...
INFO:    Creating SIF file...
[=============================================================================================================] 100 % 0s
CernVM-FS: pre-mounted on file descriptor 3

Apptainer>

In this environment, you should be able to access the EESSI software.eessi.io repository:

ls /cvmfs/software.eessi.io

To start using EESSI, see Using EESSI.

(back to overview page)