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How to log in

There are two ways to access LUNARC systems:

New to the Linux command line?

Once you log in you will be working in a Linux terminal. If you have not used one before, read the Introduction to Linux first — it covers the basic commands you will need immediately after logging in.

  • The LUNARC HPC Desktop (ThinLinc) — see the HPC Desktop guide
  • SSH terminal — described on this page
Prefer a video?

Login to LUNARC's COSMOS using SSH, including password and Pocket Pass reset (YouTube)

SSH login

Connect to COSMOS using either form:

ssh cosmos.lunarc.lu.se -l username

ssh username@cosmos.lunarc.lu.se

Server names

Method Server
SSH cosmos.lunarc.lu.se
ThinLinc (HPC Desktop) cosmos-dt.lunarc.lu.se

SSH is built into Linux and macOS. On Windows, use PuTTY — though Windows users are generally recommended to use the HPC Desktop instead.

Two-factor authentication

LUNARC uses two-factor authentication (2FA). Each login requires:

  1. Your LUNARC username and password
  2. A one-time password (OTP) from the PhenixID OneTouch app on your smartphone

First-time users

Before you can use the Pocket Pass app, you need to activate it. Follow the 2FA setup guide before attempting to log in.

First login — server fingerprints

The first time you connect, your SSH client will ask you to verify the server fingerprint. Check it against the values below before accepting:

2048 SHA256:NQ/G3C89HTTHDsNo53MueduO8s9WA4ePCCn4XV1G5do cosmos.lunarc.lu.se (RSA)
256  SHA256:Dz3UFUfoEItFI6Oee1NRmpx+r4mkD1PLnm6NKrl6a6s cosmos.lunarc.lu.se (ECDSA)
256  SHA256:cmCshUQAZ+DqFRyMntx9NbNHSDu9BExg8OJ+TX05gCs cosmos.lunarc.lu.se (ED25519)

Login sequence

A typical SSH session looks like this:

login as: joeuser
Password:
Please enter your onetime password: 123456

Enter your password first, then the OTP from your OneTouch app when prompted.

OS-specific SSH configuration

Your SSH client must be configured for keyboard-interactive login to receive the OTP prompt. Edit either /etc/ssh/ssh_config (system-wide, Redhat-based systems) or ~/.ssh/config (per-user):

Host cosmos.lunarc.lu.se
  PreferredAuthentications keyboard-interactive
  ServerAliveInterval 10

Host *
  PreferredAuthentications hostbased,publickey,keyboard-interactive,password

ServerAliveInterval 10 sends a keepalive every 10 seconds to prevent the connection from dropping during idle periods.

macOS handles keyboard-interactive login automatically — no extra configuration is needed for the OTP prompt.

To prevent the connection dropping during idle periods, add a ServerAliveInterval to ~/.ssh/config:

Host cosmos.lunarc.lu.se
  ServerAliveInterval 10

PuTTY must be configured for keyboard-interactive login:

  1. Open PuTTY and load the session for COSMOS
  2. Navigate to Connection → SSH → Auth in the left-hand tree
  3. Enable Attempt "keyboard-interactive" auth (SSH-2)

To prevent the session from dropping during idle periods, set Seconds between keepalives to a value greater than 0 under Connection.

PuTTY configured for keyboard-interactive login

Troubleshooting

SSH keeps asking for a password and never prompts for an OTP

Your Pocket Pass has not been activated. Follow the 2FA setup guide to activate it, then try again.

ThinLinc fails with "The SSH connection succeeded, but the ThinLinc server connection failed"

You are most likely using the wrong server name. ThinLinc requires cosmos-dt.lunarc.lu.se, not cosmos.lunarc.lu.se. See the server names table above.

Author: (LUNARC)

Last Updated: 2024-08-08