Singularity

Background

Singularity is a container solution created by necessity for scientific and application driven workloads. The Singularity containers can be used to package entire scientific workflows, software and libraries, and even data. This means that you don’t have to ask your cluster admin to install anything for you - you can put it in a Singularity container and run.

(see webpage https://www.sylabs.io and/or http://singularity.lbl.gov/ for details)

Build a Singularity Container

Build a container from a Singularity recipe (ubuntu1604-cuda92-ompi400.def)

wget https://wiki.ncsa.illinois.edu/download/attachments/82518873/ubuntu1604-cuda92-ompi400.def
singularity build ubuntu1604-cuda92-ompi400.simg ubuntu1604-cuda92-ompi400.def

Pull a container from Singularity Hub or Docker Hub

singularity pull docker://nvidia/cuda-ppc64le:9.2-cudnn7-devel-ubuntu16.04

Run a Singularity Container

Run a container with "exec" command

mpirun -n 4 singularity exec --nv /opt/apps/samples-image/ubuntu1604-cuda92-ompi400.simg hostname

Run a container with shell

singularity shell --nv /opt/apps/samples-image/ubuntu1604-cuda92-ompi400.simg

Build a writable Singularity container

By default, the Singularity container filesystem is read-only. There are 2 options to build a writable Singularity container.

The "--sandbox" option allows users to create a container within a writable directory (called a sandbox). It’s possible to create a sandbox without root privileges, but to ensure proper file permissions it is recommended to do so as root.

singularity build --sandbox cuda-ppc64le/ docker://nvidia/cuda-ppc64le:9.2-cudnn7-devel-ubuntu16.0
singularity shell --writable cuda-ppc64le/

The "--writable" option allows users to create a writable ext3 image. You must create writable containers as root.

singularity build --writable cuda-ppc64le.simg docker://nvidia/cuda-ppc64le:9.2-cudnn7-devel-ubuntu16.04
singularity shell --writable cuda-ppc64le.simg

Build a writable Singularity container based on a existing read-only image

Convert it to a writable directory (a sandbox):

singularity build --sandbox cuda-ppc64le-mod/ cuda-ppc64le.simg
singularity shell --writable cuda-ppc64le-mod/

Use an existing container as a target to build a new container

singularity build --writable cuda-ppc64le-mod.simg cuda-ppc64le.simg
singularity shell --writable cuda-ppc64le-mod.simg

Frequently Asked Questions

Can I run a Singularity container with x86 architecture image on an IBM ppc64le system?

Answer: Singularity can not directly run x86 binaries on a IBM Power system because the bytes of machine code are different. Users need to make sure their own images are built for "ppc64le" rather than "x86".