AImageLab-HPC

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Connecting to the Cluster

Last updated: March 29, 2026

AImageLab-HPC is accessed via SSH (Secure Shell). This page explains how to connect for the first time, how to set up SSH keys for passwordless access, and what the login nodes are intended for.

Login Nodes

The cluster provides two login nodes:

Hostname Notes
ailb-login-02.ing.unimore.it Primary login node
ailb-login-03.ing.unimore.it Primary login node

Both nodes share the same filesystems (/homes, /work) and provide an identical environment. You can use either; there is no meaningful difference from the user’s perspective.

First Connection

The first login must be made via password from a UNIMORE IP address (on-campus cable network, UNIMORE WiFi, or UNIMORE VPN). Password login from outside the UNIMORE network is not permitted.

ssh <username>@ailb-login-02.ing.unimore.it

You will be prompted for your password. On first login you will receive a temporary password via SMS (external users) or use your UNIMORE institutional credentials where applicable - see Getting Access for details.

Setting Up SSH Keys

SSH key authentication is permitted from any network and is the recommended method for day-to-day access. Once set up, you will no longer need a password to log in.

Generate a key pair (on your local machine)

If you do not already have an SSH key pair, generate one:

ssh-keygen -t ed25519 -C "<your_email>"

Accept the default file location (~/.ssh/id_ed25519) and set a passphrase when prompted. The command creates two files:

  • ~/.ssh/id_ed25519 - your private key (never share this)
  • ~/.ssh/id_ed25519.pub - your public key (this is what you copy to the cluster)

Copy your public key to the cluster

From a UNIMORE network connection:

ssh-copy-id <username>@ailb-login-02.ing.unimore.it

Or manually: append the contents of ~/.ssh/id_ed25519.pub to ~/.ssh/authorized_keys on the cluster:

cat ~/.ssh/id_ed25519.pub | ssh <username>@ailb-login-02.ing.unimore.it \
    "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys"

Test the key-based login

ssh <username>@ailb-login-02.ing.unimore.it

If successful, you will not be prompted for a password (only for your key passphrase, if you set one).

Simplify access with an SSH config entry

Add the following to ~/.ssh/config on your local machine to avoid typing the full hostname each time:

Host ailb02
    HostName ailb-login-02.ing.unimore.it
    User <username>
    IdentityFile ~/.ssh/id_ed25519

Host ailb03
    HostName ailb-login-03.ing.unimore.it
    User <username>
    IdentityFile ~/.ssh/id_ed25519

You can then connect with simply ssh ailb02.

What Login Nodes Are For

Login nodes are shared resources. They are intended for:

  • Editing files and scripts
  • Compiling code
  • Submitting and monitoring SLURM jobs
  • Short test runs (a few minutes of CPU time at most)
  • Transferring small files

Do not run long or resource-intensive processes on login nodes. Production computations, model training, and large data processing must be submitted as SLURM jobs. Processes that exceed the CPU time limit may be terminated without warning.

For large file transfers, use the dedicated data mover node ailb-data.ing.unimore.it instead of the login nodes - see File Systems and Data Management for details.

Windows Users

Native SSH is available in Windows 10 and later via PowerShell or Command Prompt. For a more complete experience, consider: