LearnApptainer.com is a free, unofficial interactive training platform for Apptainer — the rootless container runtime used on most of the world's HPC clusters. The entire simulator runs in your browser. No login required, nothing to install.
The trainer simulates a Rocky Linux 9.7 login node with Apptainer installed — exactly like logging in over SSH to a real HPC system. You get the correct bash prompt, filesystem layout, and a realistic container image cache.
| OS | Rocky Linux 9.7 (Blue Onyx) — kernel 5.14.0-427.13.1.el9_4.x86_64 |
| Apptainer | 1.3.3 — verified against apptainer.org documentation |
| Cluster | hpccluster — 12 nodes (8 compute, 3 GPU, 1 login) |
| GPUs | 12× NVIDIA A100 (3 GPU nodes, 4 GPUs each) |
| Storage | /home, /scratch, /project — bind-mountable paths |
| Cache | ~/.apptainer/cache — SIF blobs, OCI layers |
Type commands in the terminal — Apptainer commands, Linux commands — everything behaves as it would on a real HPC login node. Pull images with apptainer pull, build with apptainer build, write definition files with cat or vim, and run containers with apptainer exec.
The Commands panel in the sidebar lets you search for any command or flag. Click a result and it's pasted into the terminal — press Enter to run it.
LearnApptainer is part of a trio of companion sites covering the full HPC workflow: LearnSpack.com for building and installing software, LearnApptainer for containerizing it, and LearnSlurm.com for scheduling and running jobs on the cluster.
Unofficial community resource. Not affiliated with the Apptainer project or Lawrence Berkeley National Laboratory. Official documentation at apptainer.org/docs. Apptainer was formerly known as Singularity.
LearnApptainer, LearnSpack, and LearnSlurm are all free, with no ads or tracking. If any of the sites have saved you time — a coffee keeps the servers running and new content coming.