Usage of a HPC cluster

Here we collect some general (and by no means complete) information about usage and policies of a HPC cluster.

Structure of a HPC cluster

The structure of a HPC system is sketched in the picture above. These are the main logical building blocks:

a login node is exposed to users for access (typically via ssh),
a dedicated scheduler (the queuing system) dispatches computational jobs to the compute nodes
computation happens therefore asynchronously (in batch mode), and not on the login node.
a specific software environment is provided on the login node and on the compute node to run parallel jobs
the above cluster structure is used from commodity local machines to large scale HPC architectures (as shown below for the Summit machine at Oak-Ridge Natl Lab (ORNL), TN, USA)

Unless other means are provided, you typically connect using the ssh protocol.

From a shell terminal or a suitable app:

 ssh -Y <user>@<machine_host_name>  or
 ssh -Y -l <user> <machine_host_name>

 <user>:  Unix username on the cluster login node