Singularity to Apptainer renaming
Singularity has been renamed to Apptainer in 2022 due to legal constraints. In general, just the name has changed and all options are the same. Replacing the command `singularity` with `apptainer` should work on updated systems.
If you need a machine to build a Apptainer/Singularity container but you don't have a Linux machine at hand, where you can become root/do sudo, a way around can be a virtual machine.
Install Apptainer/Singularity
Apptainer/Singularity is available in the epel repository.
Check if you have this repo in your /etc/yum.repos.d/ directory
> grep -i "epel" /etc/yum.repos.de/*
Only if you don't find the EPEL repository, install it with
yum install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
With epel, you can install singularity straight forward
> yum clean all; yum update
> yum install -y singularity
Installing CVMFS
If you need files from CVMFS, you will have to do some more additional steps... your millage may vary and depend on your local environment.
To use CVMFS you will need a squid proxy in your network to talk to when asking for files in CVMFS - i.e., check in a machine in the same network with working CVMFS, what it's config file '/etc/cvmfs/default.local' says.
> yum install -y cvmfs cvmfs-config-default
# create/copy a config file
# e.g., if you are at CERN, you might be successful, if you copy the config file from a lxplus node
> /etc/cvmfs/default.local
# add cvmfs to the automount config
> echo "/cvmfs program:/etc/auto.cvmfs" >> /etc/auto.master
# enable and start the automounter unit
> systemctl enable autofs
> systemctl start autofs
# (reboot the box)
# run a test, if your box can reach the configured CVMFS repositories
> cvmfs_config probe