RCS-knowledge-base/singularity/20210629.Singularity-overlay.md

Overlay for Singularity Containers

"Persistent Overlays" https://sylabs.io/guides/3.5/user-guide/persistent_overlays.html

"Persistent overlay directories allow you to overlay a writable file system on an immutable read-only container for the illusion of read-write access. You can run a container and make changes, and these changes are kept separately from the base container image."