ssh-related

SSH is an essential tool for interacting with HPCs.

Linux or MacOS users can use the Terminal. Windows users can use the Command Prompt.

To have easier access to the HPC, we can create a config file at ~/.ssh/ with the following content by typing vi ~/.ssh/config in the terminal. Then we can just type ssh sulis to log in to Sulis and use sulis for transferring files, as detailed below.

Host sulis

HostName login.sulis.ac.uk

User ab123

PubKeyAuthentication yes

IdentityFile ~/.ssh/sulis

Host office

HostName nyx.mcs.le.ac.uk

User ab123

PubKeyAuthentication yes in the sample means that the server can be accessed by using the public ssh key (you need to copy your public ssh key to the server before using this).

ssh key can be generated by typing ssh-keygen in the terminal. Then you need to copy your public ssh key to the server by typing ssh-copy-id -i /path-to-key/key.pub sulis. More details regarding this aspect can be found here and here. By the way, when generating an ssh key for Sulis, it must have a passphrase and should be used exclusively for Sulis, according to here. We need to upload the public key to Sulis via here instead of using the ssh-copy-id command.

We don't want to type in the passphrase each time logging in to Sulis, a way for remembering the passphrase is mentioned here.

IdentityFile ~/.ssh/sulis indicates the private key to be used for authentication. If you cannot log in with your ssh key, try to make the config file as the above sample for explicitly indicating the private ssh key and try again.

Typing at a local terminal when transferring a file from local to the HPC:

scp -r destination-folder/ sulis:path-to-file/file

or transferring a file from the HPC to local:

scp -r sulis:path-to-file/file destination-folder/

The flag -r is required when transferring a folder.

Access to Sulis when out of campus: ssh to your Linux account at the UoL by typing "ssh username@nyx.mcs.le.ac.uk" and then ssh to Sulis from the Linux