Apptainer is an open source container platform designed to be 
simple, fast, and secure. Many container platforms are available, 
but Apptainer is designed for ease-of-use on shared systems and in 
high performance computing (HPC) environments. It features:

  An immutable single-file container image format, supporting 
cryptographic signatures and encryption.
  Integration over isolation by default. Easily make use of GPUs, 
high speed networks, parallel filesystems on a cluster or server.
  Mobility of compute. The single file SIF container format is easy 
to transport and share.
  A simple, effective security model. You are the same user inside a 
container as outside, and cannot gain additional privilege on the 
host system by default.

  Apptainer is open source software, distributed under the BSD 
License.

  Apptainer was formerly known as Singularity and is now a part of 
the Linux Foundation. When migrating from Singularity see the admin
migration documentation and user compatibility documentation.


  You shall install fakeroot for all functionalities.

  Usage example:
apptainer build slackware.sif \
  /usr/share/apptainer/examples/slackware/slackware.def