The Center for High-Performance Computing is the single most important resource for the Clark group. Within this shared computational environment, we perform chemical simulations/calculations on collections of powerful computers, storing the resulting data on robust servers. Accessing this resource may initially seem intimidating. This page will hopefully demonstrate how simply a connection to CHPC can be established, as well as give readers a set of useful tools to start navigating and creating.
This page expands upon the CHPC's personal page for getting started accessing shared resources with some additional Clark Group-specific tips. Additional help can be found online or on the CHPC's homepage.
All University of Utah students/faculty who wish to access CHPC must first set up an account. This account is tied to your university login and provides a simple and integrated way to access all the resources the CHPC provides:
IT helpdesk for personal incidents/questions
User/group usage and storage analytics
Real-time system status updates
Computing tutorials (past content and upcoming virtual lessons)
Open OnDemand, a browser-based way to access CHPC
To make an account, fill out the online account request form here.
Researchers in the Clark Group access CHPC resources via one of several networking interfaces, which help establish a connection (session) between your personal computer (the client computer or client node) and CHPC (the server computer or server node) via wi-fi or Ethernet. The number of interface options available to choose from can be overwhelming; however, at their core, each one is simply a way for users to pass commands and files back and forth from their personal computers (nodes) to the shared nodes in CHPC. The following sections will advise on several different interfaces that are commonly used in the Clark Group and demonstrate how to use these interfaces to connect to CHPC.
Figure 1. An illustration of how users connect to the CHPC computer architecture. Use this image as a reference for the language used on this page.
Below are several interface options for connecting to CHPC, how to set them up, and some of their pros and cons.
Connect directly from the command line of your personal computer. When in doubt about which of the following methods to choose, use this one first for practice, then explore other options.
Pros:
Simple to access- no setup required
Cons:
Very basic- lacks additional tools provided by third-party interface apps
(Windows) Displaying remote graphics requires additional setup
Setup:
Windows:
Open 'cmd.exe' (may also be accessed via windows 'terminal' app which is a more modern windows command line application)
MacOS:
Open Terminal or search 'terminal' in spotlight
A browser-based High Performance Computing (HPC) portal
Pros:
Good for beginners- easy to use interface
Users may run apps by clicking their icons on the dashboard
Integrated system status and personal job status tools
Access IT support directly within Open OnDemand
Simple 'drag-and-drop' file transfers
Cons:
Browser-compatibility issues
Website buffering/down-time/bugs may be present
Setup: Go to https://ondemand.chpc.utah.edu and log in with your CHPC username and password.
A remote display server suggested to users by CHPC, similar to Open OnDemand
Pros:
Good for beginners- easy to use interface
Users may log out from FastX without closing the session
Given that this is a CHPC-backed application, there is plenty of available local support
Cons:
No users within the Clark group (yet)
Setup: The CHPC has an online introduction to FastX here, which instructs users on using the browser-based version (see 'Using the FastX web-client') and the desktop version (see 'Using the FastX desktop-client')
A popular command-line and remote display server used within the Clark group
Pros:
Automatically saves commonly used server addresses for quick reconnection
Open multiple session tabs at once
Built-in text editor and file comparison tools
More tools than you may ever need
Cons:
Only available for Windows devices
Due to changes to CHPC's 2-factor authentication, file transfer is no longer drag-and-drop. Please use WinSCP or similar file transfer applications.
Setup: More info and download instructions for windows are available here.
All of the interfaces provided will use the same protocol when establishing a connection to CHPC. This method is called the SSH (secure shell) protocol. SSH is a standard for connecting to remote computers, which allows data to be transferred securely between your personal computer and CHPC, no matter which interface you decide to use. The general command to establish this connection is:
ssh username@hostname
Which is entered directly into your computer's command line. For CHPC connections this command is:
ssh uXXXXXXX@chpc_host_name.chpc.utah.edu
Where uXXXXXXX is your 7 digit university ID preceeded by 'u', and 'chpc_host_name' is the keyword for the collection (cluster) of computing nodes you want to connect to. See the next section for tips on choosing a cluster.
This decision will be motivated by the type of work you plan on doing and which clusters are currently active, but for Clark Group members, the choice generally comes down to one of two types.
Computing Clusters: These clusters consist of a Head Node and Compute Nodes. The head node meets the user when you first log in and is available to tackle day-to-day manual tasks such as copying/moving files and running small scripts. These tasks and any others that involve direct user keyboard input are called 'interactive'. The head node is powerful but is used concurrently by many users; therefore, to avoid causing network traffic, larger tasks are submitted to compute nodes, which dedicate private resources to your computing alone.
Notchpeak (hostname- notchpeak.chpc.utah.edu)
Kingspeak (hostname- kingspeak.chpc.utah.edu)
Granite (hostname- granite.chpc.utah.edu)
Lonepeak (hostname- lonepeak.chpc.utah.edu)
Interactive Clusters: These clusters are beefier than the head nodes of computing clusters and are available for longer or more computationally expensive interactive commands.
Frisco (hostname- frisco.chpc.utah.edu)
Once you've set-up your CHPC interface of choice and know which cluster you want to connect to, you can proceed to connecting to CHPC.
Local Command Line
Open your computer's command-line / terminal (see setup above)
Enter the OS-specific SSH command
Windows: Enter 'ssh uXXXXXXX@chpc_host_name.chpc.utah.edu' , replacing 'uXXXXXXX' with your uID and 'chpc_host_name' with the cluster name you would like to connect to (e.g. ssh uXXXXXXX@notchpeak.chpc.utah.edu)
Mac: Enter 'ssh -X -Y uXXXXXXX@chpc_host_name.chpc.utah.edu' , replacing 'uXXXXXXX' with your uID and 'chpc_host_name' with the cluster name you would like to connect to (e.g. ssh -X -Y uXXXXXXX@notchpeak.chpc.utah.edu)
Enter your password
Enter '1' to send a Duo 2-factor authentication push notification (for info on setting up Duo go here)
Using your phone or laptop confirm the Duo push notification to login
To exit a session type 'exit' and click enter
Note for Windows users: Windows does not have a built-in X server for X forwarding CHPC graphics windows. This means that you will have to download a 3rd party X forwarding server to see graphics displayed by CHPC. Alternatively, you may use MobaXterm, which has a built-in X server.
Open OnDemand
Log in with your username and password
From the dashboard click 'Interactive Desktop'
Select the cluster you would like to connect to from the drop-down down
Select the account and partition you would like access under from the drop-down down
Select the number of CPUs (cores) you would like to use from the drop-down down
Select the number of hours you would like your session to be active for from the drop-down down
Click 'Launch'
Once session goes from 'Queued' to 'Running' click 'Launch Interactive Desktop'
Enter your password and click enter
To exit a session type 'exit' and hit enter or close the tab. Your session will be preserved on your dashboard until its time limit expires.
FastX (Browser version)
Open up a session in a web browser by going to http://servername.chpc.utah.edu:3300 (replacing servername with one of the CHPC cluster names).
Sign in using your University of Utah uNID and associated password
To start a new session with a terminal and X forwarding click on the 'xterm' play button, this will open a new tab with an active terminal
To disconnect a session, go back to your dashbaord tab, click the three dots on the session, and choose disconnect (or close the session tab). This will disconnect you from CHPC and save your session on your dashboard for you to come back to later
To reconnect to an existing session, login to the same server, and click on a given session and hit the play button. Again the session will open in a new browser tab.
To permanently delete a session. Go to your dashboard tab, click the three dots on the session, and select terminate.
To log off you go to the pull down menu associated with your username near the top right of your web browser window and select "Sign Out".
Note: Once you have a terminal tab open, near the top of the web browser window there are a few icons - these include an online keyboard, a file manager, and settings. If you choose one of the desktops, there is also an icon to resize to full screen.
For tips on downloading and using the desktop version of fastX go here.
MobaXterm
Open MobaXterm
Select 'New session' from the session drop-down
Select the SSH option
Under 'Remote host' enter chpc_host_name.chpc.utah.edu' , replacing 'chpc_host_name' with the cluster name you would like to connect to
Click the 'specify username' box and enter your uID (uXXXXXXX replacing 'uXXXXXXX' with your uID)
Enter your password (if you haven't saved a password)
Enter '1' to send a Duo 2-factor authentication push notification (for info on setting up Duo go here)
Using your phone or laptop confirm the Duo push notification to login
To exit a session type 'exit' and click enter
Since interactive commands (on head nodes or Frisco) operate on shared resources, CHPC works to police this traffic and maintain the usability of interactive nodes. Occasionally, if a command you operate uses too many resources, CHPC will warn you that your usage is excessive and restrict your share for a short amount of time.
These emails can be scary, but they are nothing to stress about; simply CHPC working to maintain the usability of their shared resources. They should, however, be taken seriously and used to learn which commands you can run interactively and which ones should be assigned to compute nodes.
For more information on submitting larger tasks to compute nodes using batch scripting and SLURM go here.