LPCT Cluster

Overview

Welcome to the LPCT Cluster, a HPC platform featuring a heterogeneous architecture with x86 CPUs and NVIDIA GPUs.

Cluster Specifications

Compute Nodes: Close to 250 nodes
Accelerated Nodes: About 100 nodes equipped with NVIDIA GPUs
Networking: 5 high-speed interconnect switches
Storage: Over 1 petabyte (PB) of disk space mounted via NFS

Fronted Nodes

Login Nodes

The cluster provides 4 login nodes:

lpct-login1.pct.site.univ-lorraine.fr
lpct-login2.pct.site.univ-lorraine.fr
lpct-login3.pct.site.univ-lorraine.fr
lpct-login4.pct.site.univ-lorraine.fr

Visualization Nodes

Dedicated nodes for graphical applications with GPU acceleration:

2 nodes with 2× NVIDIA RTX A5000:
- lpct-visu1.lpct.site.univ-lorraine.fr
- lpct-visu2.lpct.site.univ-lorraine.fr
1 node with 4× NVIDIA GeForce GTX 1070:
- ebam-login.pct.site.univ-lorraine.fr
1 node with 4× NVIDIA GeForce GTX TITAN:
- lia-login.pct.site.univ-lorraine.fr

Access is available via:

SSH: For command-line sessions
TurboVNC: For graphical applications (Graphical Session Guide)

Graphical Session

X11 Forwarding

The simplest way to access a graphical interface on the cluster is via X11 forwarding. Use the -X flag with SSH:

$ ssh -X USER@lpct-login

For better performance, enable compression by adding the -C flag:

$ ssh -XC USER@lpct-login

TurboVNC

For higher-performance remote desktop access, use TurboVNC. Note that, only securized sessions via SSH are allowed. The required TurboVNC client version is 3.2 and can be installed from the release website of turbovnc.

Setting up a TurboVNC session

On the login node, run:
```
$ /opt/TurboVNC/bin/vncpasswd
```
and choose your VNC password
Then run:
```
$ /opt/TurboVNC/bin/vncserver
```
to start a new session
A message like this should appear:
```
Desktop 'TurboVNC: lpct-login:n (USER)' started on display lpct-login:n
```
where the number n indicates the X display number of the TurboVNC session

Managing TurboVNC sessions

To see all your VNC sessions, run:
```
$ /opt/TurboVNC/bin/vncserver -list
```
To connect to a running session, run the following command on your local machine:
```
$ /opt/TurboVNC/bin/vncviewer -tunnel USER@lpct-login:n
```
You will be prompted to enter your login password, followed by your VNC password.
Note that this is equivalent to running:
```
$ ssh -L (5900+$n):localhost:(5900+$n) USER@lpct-login
```
and then, in a second terminal:
```
$ /opt/TurboVNC/bin/vncviewer localhost:n
```
The first method uses TurboVNC's internal SSH library to create the tunnel automatically. The second method uses your system's native SSH client to create the tunnel manually, giving you more explicit control over the SSH connection.
To kill a session, use:
```
$ /opt/TurboVNC/bin/vncserver -kill :n
```

External Access

To access the cluster from an external network, you must connect through the University of Lorraine's VPN using the Cisco Secure Client.

1. Download the Client

Use your UL account to authenticate on the university's VPN portal. Select the group Universite-de-Lorraine (remember to append @ul to your username). From here, you can download the Cisco Secure Client for your machine.

2. Configure the Connection

Open the Cisco Secure Client and configure a new connection with the following settings:

Server: vpn.lothaire.net
Group: Universite-de-Lorraine
Username: your_username@lpct
Password: Your UL password

Once configured, you can connect to the VPN and will then have access to the cluster network.