Singularity

• Official Website

• Application container for scientific experiments -- just for us!?

• Its internal seems similar to Docker

• Supports X11 forwarding out-of-the-box(, and GPU acceleration?)

• Can make a container image from a docker image

• Faster to initiate container than Docker

Issues?

• Each container is contained in a single file, which brings unnecessary duplicated common system files.
  • Singularity does not utilize layered container structure like Docker.
  • A storage waste from not sharing common packages installed is expected.
• Because there is no root ptiviledge in the container out-of-the-box. we cannot use apt-get (yum for Redhat) to install missing packages after building app image.

Solved issues

• Cannot convert from a docker image
  • it seems that bug was fixed in recent source code @2018.11.
  • Can load from local docker registry (w/o HTTPS) from v3.0.2 again Related issue
• It seems it still also requires root priviledges or docker priviledges, that could be a security threat...
  • It seems not right...! Singularity containers can be run without root or in docker group