Apptainer

Apptainer is the renamed, community-governed continuation of Singularity, the container platform originally developed at Lawrence Berkeley National Laboratory for scientific computing. The project was renamed to Apptainer after the Singularity name was acquired by Sylabs, and the open-source community continued development under the new name.

Apptainer is designed for high-performance computing and shared cluster environments where users typically do not have root privileges, and its containers run as a single file without a daemon process. Docker, by contrast, requires a root-level daemon and is oriented toward enterprise application deployment rather than scientific reproducibility.

Yes, Apptainer can pull and convert Docker images from Docker Hub and other OCI-compatible registries into its native SIF (Singularity Image Format). This allows researchers to reuse existing containerized workflows built for Docker.

Apptainer is used to package scientific applications and their dependencies into portable, reproducible containers that can run across different HPC systems and supercomputing environments. Its single-file container format makes it easy to transfer and run complex computational workflows on shared computing clusters.