It is with great pleasure that I announce the general availability of Singularity version 2.2! Here’s what’s in store for version 2.2 from your favorite Git clone, download, or distribution vendor:

  • A complete rework of the back end source code to allow a much larger feature set, sanity, and facilitate contributions
  • The ability to execute completely unprivileged (does not support Singularity images) (thanks to Brian Bockelman)
  • Container execute by URI support (file, http, https, docker, etc..)
  • Integration with the Docker Registry Remote API (thanks to Vanessa Sochat):
    • stateless containers running ad-hoc
    • bootstrapping
    • importing
  • OverlayFS support - Allows for automatic creation of bind points within containers at runtime (thanks to Amanda Duffy and Jarrod Johnson)
  • Additional container formats supported (directories and archives)
  • New bootstrap definition format to handle much more complicated and intuitive recipes
  • All Singularity 2.x containers continue to be supported with this release.

Additionally I would like to extend thanks to the following organizations for being part of supporting scientific computing with Singularity:

  • Lawrence Berkeley National Laboratory (
  • Stanford University (
  • San Diego Supercomputing Center (
  • University of Nebraska-Lincoln (
  • Dartmouth (
  • Yale University (
  • University Of Liverpool (
  • Texas Advanced Computing Center (
  • Open MPI (
  • Ontropos (
  • Lenovo (
  • Intel (
  • Amazon (
  • R Systems (

Release tip: The best way to kill an idea is to take it to a meeting.