# 3. Setup Singularity¶

The Singularity image may be downloaded from Singularity Hub by users without sudoer rights by running the following:

singularity pull --name rserver-launcher-centos7.simg shub://OSC/centos7-launcher

Note

The Singularity guest needs to be the same operating system type and major version as the compute host. The provided image is for CentOS 7.

## Alternatively, Build The Singularity Image¶

Running a build is trivial but does require sudoer access to the build host.

Where Singularity is the file that defines the image. The image is just the base CentOS 7 packages plus a run script. This simplicity is because the actual executables and libraries must be bound and mounted into the container/guest at runtime from the host. By bind-mounting executables and libaries from the host system we are able to swap RStudio versions at launch time without having to update the Singuarlity image.

Likewise the runscript defined in the image uses the host $PATH which is propagated into the guest’s environment as$USER_PATH.

An example Singularity file for running RStudio:

# Ensure that the guest is the same OS type as the compute hosts that it will run on
# Here we use CentOS 7
Bootstrap: yum
OSVersion: 7
MirrorURL: http://mirror.centos.org/centos-%{OSVERSION}/%{OSVERSION}/os/$basearch/ Include: yum %labels Maintainer OSC Gateways %help This will run RStudio Server which must be mounted with dependencies into the container %apprun rserver if ! [[ "$USER_PATH" = "" ]]; then
export PATH="$USER_PATH" fi exec rserver "${@}"

%runscript
if ! [[ "$USER_PATH" = "" ]]; then export PATH="$USER_PATH"
fi

exec rserver "\${@}"