Connecting to Triton

Video

Watch this in our courses: 2022 February, 2021 June 1/2, 2021 June 2/2, 2021 January

The traditional way of interacting with a cluster is via a terminal, and Secure Shell (ssh) is the most common way of doing that. The terminal. To learn more command line basics, see our shell crash course (which can be considered a prerequisite for this series of tutorials).

Cheatsheet

  • You can connect to Triton via ssh

  • Host name is triton.aalto.fi

  • Connections available from the Aalto networks (VPN, most wired, internal servers, eduroam, aalto only if using an Aalto-managed laptop, but not aalto open),

  • VPN is best but kosh.aalto.fi is a good ssh jump host from outside (note the -J ssh option.

  • https://vdi.aalto.fi (ssh to Triton from there) and https://jupyter.triton.aalto.fi (start a terminal) provide alternatives.

Kickstart course preparation

Are you here for a SciComp KickStart course? You just need to make sure you have an account and then be able to connect via ssh (first section here), and you don’t need to worry about the graphical application parts. Everything else, we do tomorrow.

Local differences

The way you connect will be different in every site, but you should be able to get a terminal somehow.

There are different ways of connecting:

Method

Description

From where?

ssh

Standard way of connecting via command line. Hostname is triton.aalto.fi

>Linux/Mac: ssh username@triton.aalto.fi

>Windows: PuTTY (install yourself) or WSL+Linux/mac command.

Connections only from VPN and Aalto networks. kosh.aalto.fi is a good proxy host if you are not there: ssh -J username@kosh.aalto.fi username@triton.aalto.fi

VDI

“Virtual desktop interface”, https://vdi.aalto.fi, from there you have to ssh to Triton (previous row) and can run graphical programs via SSH.

Whole internet

Jupyter

https://jupyter.triton.aalto.fi provides the Jupyter interface directly on Triton (including command line).

Whole internet

Open OnDemand

https://ood.triton.aalto.fi, Web-based interface to the cluster. Includes shell access and data transfer.

VPN and Aalto networks

Getting an account

Triton uses Aalto accounts, but your account must be activated first.

Connecting via ssh

ssh is one of the most fundamental programs: by using it well, you can really do almost anything from anywhere. It is not only used for connecting to the cluster, but also for data transfer. It’s worth making yourself comfortable with this.

All Linux distributions come with an ssh client, so you don’t need to do anything. To use graphical applications, use the standard -X option, nothing extra needed.:

ssh triton.aalto.fi
# OR, if your username is different:
ssh username@triton.aalto.fi

If you are from outside the Aalto networks, use the ProxyJump option in modern OpenSSH:

ssh -J kosh.aalto.fi triton.aalto.fi
# OR, if your username is different:
ssh -J username@kosh.aalto.fi username@triton.aalto.fi

# If you do not have the -J option:
ssh kosh.aalto.fi
ssh triton.aalto.fi

When connecting, you can verify the ssh key fingerprints which will ensure security.

See the advanced ssh information to learn how to log in without a password, automatically save your username and more. It really will save you time.

If you use OpenSSH (Linux/MacOS/WSL instructions above), the .ssh/config file is valuable to set up to make connecting more seamless, with this you can run ssh triton_via_kosh instead of using the -J option - and this same triton_via_kosh will work with what you learn on the Remote access to data page!:

Host triton
     User USERNAME
     Hostname triton.aalto.fi

Host triton_via_kosh
     User USERNAME
     Hostname triton
     ProxyJump username@kosh.aalto.fi

Change your shell to bash (old Aalto accounts)

Only needed if you shell isn’t already bash. If echo bash reports /bin/bash, then you are already using bash.

The thing you are interacting with when you type is the shell - the layer around the operating system. bash is the most common shell, but the Aalto default shell used to be zsh (which is more powerful in some ways, but harder to teach with). If you joined Aalto after autumn 2018, you probably don’t need to do anything. We recommend that you check and change your shell to bash.

You can determine if your shell is bash by running echo $SHELL. Does it say /bin/bash?

If not, ssh to kosh.aalto.fi and run chsh -s /bin/bash. It may take 15 minutes to update, and you will need to log in again.

Connecting via Open onDemand

See also

Open OnDemand

[BETA / Under development]

OOD (Open onDemand) is a web-based user interface to Triton, including shell access, and data transfer, and a number of other applications that utilize graphical user interfaces. Read more from its guide.

It is only available from Aalto networks and VPN. Go to https://ood.triton.aalto.fi and login with your Aalto account.

Connecting via JupyterHub

See also

Jupyter

Jupyter is a web-based way of doing computing. But what some people forget is that it has a full-featured terminal and console included.

Go to https://jupyter.triton.aalto.fi (not .cs.aalto.fi) and log in. Select “Slurm 5 day, 2G” and start.

To start a terminal, click File→New→Terminal - this is the shell you need. If you need to edit text files, you can also do that through JupyterLab (note: change to the right directory before creating a new file!).

Warning: the JupyterHub shell runs on a compute node, not a login node. Some software is missing so some things don’t work. Try ssh triton.aalto.fi from the Jupyter shell to connect to the login node. To learn more about Jupyterlab, you need to read up elsewhere, there are plenty of tutorials.

Connecting via the Virtual Desktop Interface

If you go to https://vdi.aalto.fi, you can access a cloud-based Aalto Linux workstation. HTML access works from everywhere, or download the “VMWare Horizon Client” for a better connection. Start a Ubuntu desktop (you get Aalto Ubuntu). From there, you have to use the normal Linux ssh instructions to connect to Triton (via the Terminal application) using the instructions you see above: ssh triton.aalto.fi.

For more information, see the IT help.

Exercises

Connecting-1: Connect to Triton

Connect to Triton. Use hostname to verify that you are on Triton. List your home directory and work directory $WRKDIR.

Connecting-2: Test a few command line programs

Check the uptime and load of the login node: uptime and htop (q to quit - if htop is not available, then top works almost as well). What else can you learn about the node?

(optional, Aalto only) Connecting-3: check your default shell

Check what your default shell is: echo $SHELL. Go ahead and change your shell to bash if it’s not yet (see below). This $SHELL syntax is an environment variable and a pattern you will see in the future.

This is not needed for recent Aalto accounts but is a good exercise anyway.

(advanced, to fill time) Connecting-5: shell crash course

Browse the Linux shell crash course and see what you do and don’t know from there. Decide your future shell learning plan.

What’s next?

The next tutorial is about software availability in general.