Connecting to a cluster using myApps (web browser)
For easier access to HPC resources, IT Services runs an instance of Oracle Secure Global desktop called myApps to provide web based access to CLI terminals, text editors within interactive sessions for the ShARC, Bessemer and Training HPC clusters.
Important
The myApps service is only accessible on Bessmer and ShARC (not Stanage).
In order to access the HPC clusters you must set up a VPN connection and MFA. Also see section Whether/how you can connect below.
The web browser method of access to ShARC and Bessemer is recommended. This method works well for most browsers on all the common computing platforms (Linux, Windows, Mac), however we recommend Chrome or Firefox.
How to login to the myApps service
To login to ShARC or Bessemer click the following link: Connect via myAPPs Portal
If you are logging in for the first time, select Client Options on the myApps Portal page (bottom right) and then click the HTML5 option to run myApps entirely within your browser.
Alternatively you can select option 1 to download and install the client for your system (Windows, Mac, or Linux).
Hint
Usernames to connect with all HPC services will be the same as those you use to login to MUSE not the prefix on your email address.
Enter your username and password on the myApps Portal login page.
Once you have managed to login, you will see a window with applications on the left hand panel.
There are icons for ShARC Applications & Bessemer Applications respectively.
For each of these you can select a HPC interactive job or a HPC terminal (where HPC choices are ShARC or Bessemer).
The interactive job is equivalent to a qsh/qrshx or srun session on a worker node.
The terminal is equivalent to a login node session from which you can use qsh/qrshx, qrsh, qsh-vis or srun respectively.
Connecting to a cluster using SSH
Hint
Usernames to connect with all HPC services will be the same as those you use to login to MUSE not the prefix on your email address.
The most versatile way to run commands and submit jobs on one of the clusters is to use a mechanism called SSH, which is a common way of remotely logging in to computers running the Linux operating system.
To connect to another machine using SSH you need to have a SSH client program installed on your machine. macOS and Linux come with a command-line (text-only) SSH client pre-installed. On Windows there are various graphical SSH clients you can use, including MobaXTerm.
Warning
The University Connect for China (UCC) is not the same service as the SSL VPN service and will not grant access to the HPC clusters. Users of the UCC must disconnect the UCC and connect to the SSL VPN in order to connect to the HPC clusters.
Warning
Eduroam no longer grants direct access to the clusters. If using Eduroam, you must keep the VPN connected at all times while using the clusters.
Valid methods of connecting to the University clusters using SSH (or the related protocols SCP and SFTP) include:
Connecting while in a campus building using wired ethernet;
Connecting while on campus using Eduroam or off campus after establishing a VPN connection (required);
Connecting while off campus without a VPN connection using the HPC SSH gateway.
Connecting using a password or SSH public key authentication will determine whether Multifactor Authentication (MFA) will be mandatory during the login process. The authentication requirements per cluster are summarized below:
Cluster |
From campus or via VPN |
From off campus and without a VPN connection |
|---|---|---|
Bessemer |
Password + DUO MFA or public key |
Not permitted (unless using the HPC SSH gateway service) |
ShARC |
Password + DUO MFA or public key |
Not permitted (unless using the HPC SSH gateway service) |
Stanage |
Password + TOTP MFA or public key |
Not permitted (unless using the HPC SSH gateway service) |
Connecting with a password
If connecting using your password, MFA will be mandatory. Depending on the cluster, the type of MFA may be standard University DUO MFA, or TOTP MFA.
On the Stanage cluster, when you connect you will be prompted for your password and a verification code. Enter your password and the current TOTP code for your verification code. This process should look like the following in a terminal:
ssh test@stanage.shef.ac.uk
Password:
Verification code:
Last login: Wed Apr 12 17:09:24 2023 from r.x.y.z
*****************************************************************************
* Stanage HPC cluster *
* The University Of Sheffield *
* https://docs.hpc.shef.ac.uk *
* *
* Unauthorised use of this system is prohibited. *
*****************************************************************************
[test@login1 [stanage] ~]$
If you have not setup your Stanage TOTP MFA, please follow the steps published at: Stanage TOTP multifactor authentication setup
On the Bessemer cluster, when you connect you will be prompted to via a push notification to your DUO device to approve access or must enter a one-time code from your University provided hardware token which is associated with your DUO account.
If you have not setup your University DUO MFA, please follow the steps published at: https://www.sheffield.ac.uk/it-services/mfa/set-mfa
On the ShARC cluster, when you connect you will be prompted to via a push notification to your DUO device to approve access or must enter a one-time code from your University provided hardware token which is associated with your DUO account.
If you have not setup your University DUO MFA, please follow the steps published at: https://www.sheffield.ac.uk/it-services/mfa/set-mfa
In addition, if you do not have MFA enabled on your account then you will not be able to login from off campus without using the VPN.
Connecting with SSH keys
If connecting using SSH public keys, the following policy applies around their use:
Policy on the use of SSH public key authentication:
All access to TUOS HPC systems via SSH public/private keypairs should use private keys that were encrypted with a passphrase at creation time.
All SSH private keys used to access TUOS HPC systems must be never be decrypted and stored as plaintext on any computer, at any time.
Public key access should be from single-user machines (not shared machines) without good reason.
SSH agent forwarding should not be used without good reason.
Unencrypted private keys should not be stored on TUOS HPC systems.
To discuss exceptions to this policy please contact research-it@sheffield.ac.uk
Suggested SSH clients
SSH client software on Windows
We recommend the use of MobaXterm on Windows systems and users will find MobaXterm available on the University’s managed desktops by default. For personal systems you can download and install the Installer edition of MobaXterm.
After starting MobaXterm you should see something like this:
You should create a session profile for your login for each cluster by clicking Session in the top left, and then SSH.
Enter the details for the cluster in the Remote host box, choosing
bessemer.shef.ac.uk,sharc.shef.ac.ukorstanage.shef.ac.uk.Now click the Specify Username checkmark and enter your username.
Please ensure that the checkmark for X11 Forwarding is ticked or GUI applications will be unable to open.
Please ensure that that Use SCP protocol is also ticked (or depending on MobaXterm version select SCP (enhanced speed) option from the SSH-browser type dropdown menu) .
Now click OK to save your session profile.
You should add a session for each cluster.
You can now double click on this session profile to start connecting at which point you will be prompted for your username, password and then with a Duo MFA prompt (or a request for your TOTP verification code on Stanage). Please enter these details and your terminal will connect as shown below.
You may be asked to submit your username and password with a second MFA prompt in order for the file browser to work correctly. On a successful login you should be presented with a screen like the below:
Note
When you login to a cluster you reach one of two login nodes.
You should not run applications on the login nodes.
Running the interactive job command, qrshx (ShARC) or srun --pty bash -i (Bessemer & Stanage), gives you an interactive terminal
on one of the many worker nodes in the clusters.
Running commands from a terminal (from the command-line) may initially be unfamiliar to Windows users but this is the recommended approach for running commands on Sheffield HPC clusters as it is the idiomatic way of interfacing with the Linux clusters.
SSH client software on Mac OS/X and Linux
Linux and macOS (OS X) both typically come with a command-line SSH client pre-installed.
If you are using macOS and want to be able to run graphical applications on the clusters then you need to install the latest version of the XQuartz X Windows server.
Open a terminal (e.g. Gnome Terminal on Linux or Terminal on macOS) and then go to Establishing a SSH connection.
Establishing a SSH connection
Hint
Usernames to connect with all HPC services will be the same as those you use to login to MUSE not the prefix on your email address.
Once you have a terminal open run the following command to log in to a cluster:
ssh -X $USER@$CLUSTER_NAME.shef.ac.uk
Here you need to:
replace
$USERwith your IT Services username (e.g.te1st)replace
$CLUSTER_NAMEwithbessemer,sharcorstanage.
Note
macOS users: if this fails then:
Check that your XQuartz is up to date then try again or
Try again with
-Yinstead of-X
After typing in this command hit enter to start connecting at which point you will be prompted for your username, password and then with a Duo MFA prompt.
This should give you a prompt resembling the one below:
[te1st@login1 [stanage] ~]$
At this prompt if you would like an interactive session you can type:
srun --pty bash -i
Like this:
[te1st@login1 [stanage] ~]$ srun --pty bash -i
Which will start an interactive session, which supports graphical applications resembling the below:
[te1st@node001 [stanage] ~]$
[te1st@bessemer-login1 ~]$
At this prompt if you would like an interactive session you can type:
srun --pty bash -i
Like this:
[te1st@bessemer-login1 ~]$ srun --pty bash -i
Which will start an interactive session, which supports graphical applications resembling the below:
[te1st@bessemer-node001 ~]$
[te1st@sharc-login1 ~]$
At this prompt if you would like an interactive session you can type:
qrshx
Like this:
[te1st@sharc-login1 ~]$ qrshx
Which will start an interactive session, which supports graphical applications resembling the below:
[te1st@sharc-node001 ~]$
Note
When you login to a cluster you reach one of two login nodes.
You should not run applications on the login nodes.
Running the interactive job command, qrshx (ShARC) or srun --pty bash -i (Bessemer & Stanage), gives you an interactive terminal
on one of the many worker nodes in the clusters.
What if I cannot use the VPN or I need a persistent long term connection
Direct SSH access to the HPC clusters from off campus is not possible without the use of VPN. However if you are unable to use VPN we also provide an SSH gateway service to allow off-site SSH access to our HPC clusters.
Note
Access to the HPC SSH gateway service requires that you have an existing HPC account.
You must additionally request access to the HPC SSH gateway by emailing research-it@sheffield.ac.uk including a justification for your request.
If the cluster access can be handled via the usage of the SSL VPN without undue effort, your request will not be granted.
For more information see HPC Gateway Service Details.
What Next?
Now you have connected to a cluster, you can look at how to submit jobs on the Job Submission and Control page or look at the software installed on Bessemer, ShARC and Stanage