This repository contains the framework for a very basic HPC cluster based on Vagrant, Ansible, and OpenHPC. It is just enough to build four nodes, a frontend, and a master node on your laptop or desktop system. From there, you can customize it however you wish!

1. Install Vagrant: https://www.vagrantup.com/
2. Clone this repository
3. Run the gensshkeys.sh script to generate ssh keys in the ansible repository
4. (Optional) Copy localenv.sh.in to localenv.sh and populate it with any local environment variables you need during the vagrant provisioning step (HTTP proxy information, for example)
5. Run vagrant up to fire up the cluster
6. Once the cluster is booted, you can run vagrant ssh master to log in to the master node, or vagrant ssh fe1 to log in to the frontend
7. Run sinfo on the frontend or master node to see if Slurm sees that your nodes are up. If they are not, run sudo scontrol update nodename=node[01-04] state=resume to wake them up.
8. Start using your cluster! At this point, you should be able to run a simple test across the cluster (srun -N 4 /bin/hostname) or run some more complex jobs.
9. When you are done, shut down your cluster by logging out of it and running vagrant halt.
10. If you want to completely rebuild your cluster, run vagrant destroy, and then run vagrant up again.

This virtual cluster is built around convenience, not security. It uses Vagrant's default ssh keys for convenience, and it contains some private keys (for munge, for example). This is good enough to run on an isolated desktop or laptop for experimentation, but you shouldn't plan to base an actual cluster configuration on its ansible repository without doing a good security sanity check.