Apptainer is a secure container technology designed to be used on for high performance compute clusters. This workshop will focus on how to use Apptainer as well as how to make use of tools such as Conda and Spack within Apptainer.By the end of these sessions, one:will have learnt about Apptainer and how it is installed and used on our computer clusters,how to build an Apptainer container image,how to install tools such as Conda/Spack from inside an Apptainer container shell, and,how to use Apptainer containers within job submission scripts.Level: IntroductoryLength: Two 3-Hour SessionsFormat: Lecture + Hands-onPrerequisites: Experience using Alliance compute clusters, e.g., using the BASH shell and submitting jobs.:: Thurs. June 13 ::09:00 to 12:0013:30 to 16:30----------------------------------------------------------------------Registration linkCompute Ontario Summer School is a series of online courses on Advanced Research Computing, High Performance Computing, Research Data Management, and Research Software. It runs from June 3 to June 21, 2024. The courses are delivered each workday from 9:00am to 4:30pm (EDT) with a lunch break,  in two parallel streams. Pick-and-choose the course(s) you want to attend. Registration is free. Please register early as  courses have a limited capacity. The Summer School is jointly delivered by SHARCNET, SciNet, Centre for Advanced Computing, in collaboration with the Alliance and RDM experts from across Ontario and Canada.