Please read the common steps first.


udocker is not Docker.

udocker provides four modes for running containers as a non-root user:

  1. Pn: Proot mode
  2. Fn: fakechroot mode
  3. Rn: rootless runc mode
  4. Sn: Singularity (now called Apptainer) mode

The third mode (Rn) falls into the scope of Rootless Containers, and the fourth mode (Sn) also does when it runs in non-setuid mode, but the others do not: Pn and Fn are not containers (in our view).

For futher information, see https://github.com/indigo-dc/udocker/