Connecting to Triton¶

Video

Watch this in the Winter Kickstart 2021 course

The traditional way of interacting with a cluster is via a terminal, and Secure Shell (ssh) is the most common way of doing that, but some clusters have other ways of getting a terminal (such as Jupyter or virtual desktops). Still, the command line is the most powerful way of doing this.

Prerequisites

The shell crash course is a prerequisite to this material (and the tutorial in general).

Summary:

You can connect to triton.aalto.fi via ssh from Aalto and CSC networks. Aalto networks include: Wired workstation networks, eduroam, and the aalto wireless network only if you are using an Aalto managed laptop (otherwise aalto is like aalto open). If you connect to the Aalto VPN, you will be on the Aalto networks.

For SSHing to Triton from outside of your department or CSC, please login first to a university server (like kosh.aalto.fi or taltta.org.aalto.fi) and then open a session to triton.aalto.fi - or use the -J option in modern ssh.

Important

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

Note

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	About	From where?
ssh	Works everywhere, from everywhere. Firewalls may make things hard sometimes.	Aalto networks only, otherwise ssh to kosh and then Triton
https://jupyter.triton.aalto.fi	Jupyter interface, but provides shell access via web browser.	Whole internet
https://vdi.aalto.fi	Virtual desktop, from there you have to `ssh` to Triton anyway but gets you past firewalls and can run graphical programs via SSH.	Whole internet

Connecting via ssh¶

Linux¶

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

Mac¶

ssh is installed by default, same as Linux. Run it from a terminal, same command as Linux. To run graphical applications, you need to install an X server (XQuartz).

Windows¶

You need to install a ssh client yourself: PuTTY is the standard one. If you want to run graphical programs, you need an X server on Windows: see this link for some hints. (Side note: putty dot org is an advertisement site trying to get you to install something else.)

You should configure this with the hostname, username, and save the settings so that you can connect quickly.

If you are outside the Aalto networks, you need to first connect to kosh.aalto.fi or some other server, and then use the Linux instructions to connect to Triton.

Advanced options¶

You can verify the ssh key fingerprints.

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.

ssh is one of the most fundamental Linux programs: by using it well, you can really do almost anything from anywhere. The .ssh/config file is valuable to set up. If ssh is annoying to use, ask for some help in getting it working well.

Exercise¶

Connect to Triton. List your home directory and work directory $WRKDIR.
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?
Check what your default shell is: echo $SHELL. Go ahead and change your shell to bash if it’s not yet (see below).

Change your shell to bash (Aalto)¶

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 https://jupyter.triton.aalto.fi ¶

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.aaalto) and log in. Select “Slurm 5 day, 2G” and start.

To start a terminal, click File→New→Terminal - you do anything you need to do from here, same as ssh. 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!).

To learn more about Jupyterlab, you need to read up elsewhere, there are plenty of tutorials.

Connecting via https://vdi.aalto.fi ¶

If you go to https://vdi.aalto.fi, you can access a cloud-based Aalto 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 ssh instructions (via the Terminal application) using the instructions you see above: ssh triton.aalto.fi.

For more information, see the IT help.

What’s next?¶

The next tutorial is about software availability in general.