singularity

HPC container runtime without root privileges

TLDR

Run container

$ singularity run [container.sif]

Execute command

$ singularity exec [container.sif] [command]

Shell into container

$ singularity shell [container.sif]

Build from definition

$ singularity build [output.sif] [definition.def]

Pull from registry

$ singularity pull [docker://ubuntu:latest]

Build sandbox

$ singularity build --sandbox [directory] [docker://ubuntu]

SYNOPSIS

singularity command [options] container [args]

Singularity (now Apptainer) is a container runtime designed for high-performance computing (HPC) environments where Docker's root-privilege model is not practical. Containers run as the invoking user without requiring a daemon or elevated privileges, making it safe for shared multi-tenant clusters.Unlike Docker, Singularity integrates tightly with the host system by default, sharing the user's home directory, network, and other filesystems. This makes it straightforward to use existing data and tools inside containers. Images are stored as single SIF files that are portable and can be built from Docker images, definition files, or pulled directly from registries.The tool enables reproducible science by packaging complete software environments into immutable containers that produce consistent results across different computing systems.

PARAMETERS

run

Run container.

exec

Execute command.

shell

Interactive shell.

build

Build container.

pull

Download image.

--sandbox

Writable directory.

--fakeroot

Rootless build.

INSTALL

sudo dnf install apptainer

sudo pacman -S apptainer

sudo apk add apptainer

sudo zypper install apptainer

brew install apptainer

nix profile install nixpkgs#apptainer

CAVEATS

Not Docker-compatible at runtime (no Docker socket, no daemon). Building SIF images traditionally requires root or user namespaces; use --fakeroot to build without root. Now maintained as two forks: Apptainer (Linux Foundation) and SingularityCE (Sylabs).

HISTORY

Singularity was created at Lawrence Berkeley Lab for running containers in HPC environments without privileged access.