Getting Started

Prerequisites

Before accessing the Prometheus cluster, you need:

• A valid cluster account (contact your MRG leader)
• SSH client installed on your local machine
• Basic familiarity with Linux command line

Generate SSH Keys

The Prometheus cluster uses RSA key authentication for secure access. You need to generate a public/private key pair:

Step 1: Create SSH Key Pair

Open your terminal and run:

ssh-keygen

Follow the on-screen instructions. This creates:

• Private key: ~/.ssh/id_rsa (keep this secure!)
• Public key: ~/.ssh/id_rsa.pub (share this with administrators)

Step 2: Secure Your Private Key

For Linux/Mac users, set proper permissions:

chmod 600 ~/.ssh/id_rsa

Step 3: Request Cluster Access

1. Send your public key to your MRG leader
2. Request a Prometheus account
3. Wait for account confirmation

Step 4: Add Passphrase (Optional but Recommended)

For additional security, add a passphrase to your key:

ssh-keygen -p -f ~/.ssh/id_rsa

Connect to Prometheus

Configure SSH Client

Create or edit ~/.ssh/config file with the following content:

Host prometheus
  Hostname prometheus.cyens.org.cy
  User <your-username>
  IdentityFile ~/.ssh/id_rsa

Replace <your-username> with your actual cluster username.

Connect via SSH

Once your account is activated, connect using:

ssh prometheus

You should now be logged into the Prometheus head node!

First Login Setup

Check Your Environment

# Check current directory
pwd

# List available partitions
sinfo

# Check your groups
groups

# View your home directory quota
quota -us

Understand the File System

# Your home directory (20GB limit)
ls -la /trinity/home/$USER

# Shared group storage (30TB per group)
ls -la /lustreFS/data/

# Check group quota
lfs quota -gh <group-name> /lustreFS/

Cluster Architecture Overview

The Prometheus cluster consists of:

Head Node

• Login and job submission point
• DO NOT run compute jobs here
• Used for file management and job scheduling

Compute Nodes

• gpu[01-08]: 8 nodes with A5000 GPUs (8 GPUs each)
• gpu09: 1 node with A6000 Ada GPUs (4 GPUs)
• 512GB RAM and 32 CPU cores per node

Storage Systems

• /trinity/home/: Personal home directories (SSD, 20GB limit)
• /lustreFS/data/: Shared group storage (305TB Lustre filesystem)
• Local storage: 1TB NVMe on each compute node

Important Usage Rules

Checking Cluster Status

# View partition information
sinfo

# Check job queue
squeue

# Check your running jobs
squeue -u $USER

# View detailed node information
scontrol show nodes

Example sinfo output:

PARTITION AVAIL  TIMELIMIT  NODES  STATE NODELIST
defq*        up   infinite      6  idle~ gpu[03-08]
defq*        up   infinite      1    mix gpu02
defq*        up   infinite      1   idle gpu01
a6000        up   infinite      1    mix gpu09

Next Steps

Now that you’re connected to Prometheus:

1. Set up your development environment - See Environment Modules
2. Learn about partitions and queues - Read Partitions & Queues
3. Submit your first job - Follow Job Submission
4. Configure VS Code (optional) - See VS Code Setup

Getting Help

• Cluster status: Use sinfo and squeue commands
• Documentation: Check /opt/cluster/docs/ on the cluster
• Support: Contact your MRG leader
• System issues: Report to cluster administrators

Common First-Time Issues

“Permission denied (publickey)”

• Verify your public key was added to the cluster
• Check your SSH config file syntax
• Ensure private key permissions are correct (chmod 600)

“Connection refused”

• Verify the hostname: prometheus.cyens.org.cy
• Check if you’re connected to the internet
• Confirm your account is activated

“Quota exceeded”

• Home directory has a 20GB limit
• Use group storage in /lustreFS/data/ for large files
• Check usage with quota -us