Remotely building

Actually possible with Singularity account. More details at https://sylabs.io/guides/3.6/user-guide/cloud_library.html

singularity remote login

Create account and tokenfile at [https://cloud.sylabs.io/](Sylabs Cloud)

singularity remote login --tokenfile mytokenfile

Build an image

singularity build --remote focal.sif docker://ubuntu:focal