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Connecting to the cluster

Prerequisites

To connect to the cluster, you need to use a terminal application. These are available on Linux and MacOS but may require configuration or installation on Windows. See the relevant section of the ScienceCloud Training Handout for more detail.

Connecting with a password

You can connect to the cluster using your UZH shortname and Active Directory (AD) password, like so

ssh shortname@cluster.s3it.uzh.ch

After running the command you will be prompted for your password. In most cases, your AD account password will be the same as your Email/Collaboration password. If you are unable to log in using your Email/Collaboration password, you would need to update your AD password in the Identity Manager. Please note that there will be no echo as you type your password; i.e., nothing will be displayed when you type each character.

Passwordless authentication

First, create an SSH key on your local laptop/computer using

ssh-keygen -t rsa -b 4096

Note

If you use the default names offered by the ssh-keygen command, your private key and public key will be called ida_rsa and id_rsa.pub respectively. Make sure to run the commands below using whatever name values you've chosen for your keys (i.e., update the commands accordingly).

Then, once you have located the public key that you just created (if you use the default name, it will be called id_rsa.pub located in the ~/.ssh folder), you will need to add this key to the authorized_keys file on the ScienceCluster. You have 2 options when doing so:

Option 1: Use ssh-copy-id from your client

You can use ssh-copy-id to add the public key.

From Mac, Linux, or WSL on Windows:

ssh-copy-id -i ~/path/to/local/your_public_key_name.pub user@cluster.s3it.uzh.ch

This will add the public ssh key to the ScienceCluster, stored as a new line in the file ~/.ssh/authorized_keys.

Option 2: Use a terminal-based text editor from the server

Using a terminal-based text editor to edit the authorized_keys file is also an option if you prefer a more manual approach.

First, it is suggested to make a backup of the existing authorized_keys file (if there is one), in case you make any errors during this process.

cp ~/.ssh/authorized_keys ~/.ssh/authorized_keys_copy

If there is no current authorized_keys file on the ScienceCluster, you can create a new file with the the nano text editor:

nano ~/.ssh/authorized_keys

This command will open the Nano text editor and allow you to edit the new authorized_keys file. It is important to note: each line of the authorized_keys file is a public ssh key.

To add a new public ssh key, simply move the cursor to a new line and paste the desired public ssh key. When you are finished, exit the nano editor with CTRL+x. To confirm type y then ENTER.

For reference, you can print the value of your public key if you run cat ~/.ssh/your_public_key_name.pub from the laptop/computer where you generated the key pair. The entire printed value will be what you copy/paste into the ~/.ssh/authorized_keys file on the ScienceCluster.

Verify a new public ssh key

Once you have added the public ssh key to the authorized_keys file, you should be able to access the ScienceCluster using:

ssh -i ~/.ssh/your_private_key user@cluster.s3it.uzh.ch

Last update: November 10, 2021