Secure cluster connection

SSH keys

Managed research-computing systems normally use SSH keys instead of passwords. A key pair has two parts: a public key that can be shared with the system and a private key that must remain on your own computer. Connection works only when the two keys match.

Linux / mac

Create a key pair

Run the following command in a terminal. The filename is a local label, so you can choose another clear name if you use it consistently.

ssh-keygen -t ed25519 -f research_cluster

The command creates research_cluster, the private key, and research_cluster.pub, the public key. Add a passphrase when prompted so that the private key is protected if your computer is lost or shared.

Share the public key safely

Before connecting to a managed cluster, ask the administrator of University how public keys are accepted for that system. Share only the .pub file. Never share the private key, your passphrase, passwords, or access tokens.

Keep the private key in ~/.ssh/ with restricted permissions. A useful check is:

chmod 700 ~/.ssh
chmod 600 ~/.ssh/research_cluster

Build a reusable connection profile

Most SSH clients read connection profiles from ~/.ssh/config. Replace the placeholders with the host name and user name provided for your own learning environment.

Host research-cluster
    HostName CLUSTER_HOSTNAME
    User USER_NAME
    IdentityFile ~/.ssh/research_cluster

You can then connect with a short command:

ssh research-cluster

Learn the access workflow

Every research-computing system has its own account, network, and authentication rules. Read the local access instructions supplied by your institution, then practise the sequence in a small test environment before transferring research data or starting a large job.

If the connection fails, record the exact command, the complete error message, and the point at which it occurs. This evidence is more useful than a screenshot alone when you review the problem or ask for help.

Windows

Create a key pair

Use an SSH client that can create and manage keys. Create an ed25519 key pair, set a passphrase, and store the private key in a protected folder. The public key normally ends with .pub.

Configure a connection

Enter the host name, user name, and private-key location supplied for your own system. Save the profile with a meaningful name such as research-cluster. Do not copy credentials from another learner or reuse a private key that belongs to someone else.

Test deliberately

Make one connection attempt before moving files or launching software. Confirm the remote prompt, check your working directory with pwd, and exit cleanly with exit. This small practice loop helps you distinguish an access issue from a later software or scheduler problem.

Connection learning checklist

1. Create one protected key pair.
2. Share only the public key through the local process.
3. Save a reusable profile with placeholders replaced.
4. Test one short SSH session.
5. Record the command and error text if something fails.

Safe practice rule: never publish private SSH keys, passphrases, passwords, access tokens, participant information, or restricted research data.