The container builder service in uses the :py~idmtools_platform_comps.utils.singularity_build.SingularityBuildWorkItem class, which can use as input a .def (Singularity container defiinition) file (the instructions or blueprint for building the container - .sif file), and then writes it to an asset collection id file to be available as part of an asset collection on . You can then use the built container for running simulations on .
For more information about Singularity builds on , see /platforms/comps/singularity_build.