This document will cover various environment variables that you can set to control the build of your image. If you are looking for the admin setup for Singularity on a shared resource, see the separate Singularity Administration Guide.

Cache Folders

To make download of layers for import and pull faster and less redundant, we use a caching strategy. By default, the Singularity software will create a set of folders in your $HOME directory for docker layers, Singularity Hub images, and Docker metadata, respectively:

$HOME/.singularity
$HOME/.singularity/docker
$HOME/.singularity/shub
$HOME/.singularity/metadata

Fear not, you have control to customize this behavior! If you don’t want the cache to be created (and a temporary directory will be used), set SINGULARITY_DISABLE_CACHE to True/yes, or if you want to move it elsewhere, set SINGULARITY_CACHEDIR to the full path where you want to cache. Remember that when you run commands as sudo (for example, with bootstrap this will use root’s home at /root and not your user’s home.

Pull Folder

For details about customizing the output location of pull, see thepull docs. You have the similar ability to set it to be something different, or to customize the name of the pulled image.

Support

Have a question, or need further information? Reach out to us.