1. System access

System Access

To ensure a secure login session, users must connect to the login node using the secure shell SSH protocol. Data movement must be done using the secure protocols sftp and/or scp.

Before any login sessions can be initiated using ssh, a working SSH client needs to be present in the local machine. Wikipedia is a good source of information on SSH in general and provides information on the various clients available for your particular operating system, but here we'll cover common examples for Windows 7, Ubuntu Linux and Mac OS Mavericks.

While you can send batch jobs to the whole SNOW cluster, user interactive sessions are restricted to the login node, called hpc.dtic.upf.edu 

Connecting to SNOW from a Windows client:

You need to install on your workstation a set of free tools to interact with the cluster:

  • Putty
  • XMing
  • FileZilla / WinSCP

Alternatively, you can choose the XManager Enterpsuite, that provides all tools on a single package. This tool is not free, but it will run without limitations for a 30-day period. 

Program URL Purpose
Putty www.putty.org Free SSH client
X-Ming sourceforge.net/projects/xming      X client, to be used with Putty
FileZilla www.filezilla.org FTP / FTPs / SFTP client
X-Manager enterprise   www.netsarang.com Enterprise class SSH suite. Includes all tools on a single package 

In this tutorial, we'll work with Putty and Xming. 

  • Download and install the Putty client. It's a single .exe file, place it on some folder on your hard disk
  • Execute putty, and configure X forwarding options

  • Download and install XMing. The following options are recommended:

  • Depending on your Windows firewall configuration, Windows will  need to be configured to have the ports open. If you use a firewall software, please refer to software manufacturer's support to allow a program through the firewall.

  • Open a ssh connection to the server hpc.dtic.upf.edu. The first time, you'll geta warning for the SSL signature key coming from hpc.dtic. Accept it permanently to avoid this window coming out every time:

  • Use your DTIC username and password to get access to the server. You'll get additional information about the DTIC username here.

Connecting to SNOW from a Linux client:

Connecting to SNOW from a linux machine is pretty easy, as everything is built in by default in every distribution. Simply open a terminal and type 'ssh -X username@hpc.dtic.upf.edu', where:

  • username is your DTIC user, in the usual form nsurname
  • -X tells your Linux client to forward and manage the graphical X sessions you eventually need to open over hpc.dtic.upf.edu
ivan@ubuntuvm1$ ssh -X ijimenez@hpc.dtic.upf.edu

Connecting to SNOW from a Mac OS client:

You'll need to install a couple of packages to be able to open SSH connections and make SFTP / FTPs connections:

Program URL Purpose
XQuartz xquartz.macosforge.org/landing/                   Free SSH client with X embedded support                                            
Cyberduck                         cyberduck.io Free FTPs / SFTP client
  • Download XQuartz from the project webpage
  • Double click to install the package with the default options
  • Once installed, the application will dock on the application menu. Click to launch it
  • Once opened, the procedure is similar to Linux. Type the following command (type your username in place of 'uhpc')
bash-3.2$ ssh -X uhpc@hpc.dtic.upf.edu