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).
Abstract
You can connect to Triton via ssh
Host name is
triton.aalto.fiConnections available from the Aalto networks (VPN, most wired, internal servers,
eduroam,aaltoonly if using an Aalto-managed laptop, but notaalto open),VPN is best but
kosh.aalto.fiis a good ssh jump host from outside (note the-Jssh 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
>Linux/Mac: >Windows: PuTTY (install yourself) or WSL+Linux/mac command. |
Connections only from VPN and Aalto networks.
|
VDI |
“Virtual desktop interface”, https://vdi.aalto.fi, from there you have to
|
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
ssh is installed by default, usage is the same as in the
Linux tab after starting the Terminal application. To run
graphical applications, you need to install an X server
(XQuartz).
Install the Windows Subsystem for Linux and then use the Linux instructions. This will give you a top-level interface to scientific work on your computer and is highly recommended.
This may not work if you do not have proper admin rights on your computer (e.g. if it is university managed). Ask your IT support well in advance for help!
If you can’t use WSL, then you can install a separate terminal application.
PuTTY is the standard SSH client. 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 PuTTY 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 (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
Aalto: Change your shell to bash
Only needed if you shell isn’t already bash. If echo $SHELL
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). Depending on
when you joined Aalto, your default might already be bash.
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
[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 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 but recommended) Connecting-4: SSH configuration
If you use Linux/MacOS/WSL, set up a .ssh/config file as shown
above. Customize it to suit your case. (see above and
SSH for more info)
(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.
See also¶
What’s next?¶
The next tutorial is about software availability in general.