Using the Clusters via a Web Browser

Once you've connected to the clusters via a web browser (using OnDemand), you are now ready to use OnDemand's various options for working on the clusters. This page details your options when working within OnDemand. 

If you find yourself needing more to do more than what's possible within OnDemand–such as installing new software, doing parallel programming, etc.–we recommend working with the clusters through shell access and linux commands, as explained in our Guide to the Princeton Research Computing Clusters.

Working with Files in OnDemand

Before working on the cluster, is it important to understand where different types of files should be stored in the folder hierarchy. Therefore, before proceeding, we highly recommend reviewing our Data Storage page for this information.

Access the OnDemand page for Files

  1. Connect to your cluster of choice via the web browser.
  2. Click “Files” 
  3. Select
    “Home directory”
    Or
    "/scratch/network/<user>" (for Adroit) or "/scratch/gpfs/<user>" (for other clusters)

Create a folder (watch video)

  1. Connect to your cluster of choice via the web browser.
  2. Click “Files”
  3. Select
    “Home directory”
    Or
    "/scratch/network/<user>" (for Adroit) or "/scratch/gpfs/<user>" (for other clusters)
  4. Click “New Directory”
  5. Enter directory name
  6. Click “OK”
  7. Directory has been created. You can navigate to it by selecting it in the files interface, and now you can add files there.

Upload a file (watch video)

  1. Connect to your cluster of choice via the web browser.
  2. Click “Files”
  3. Select
    “Home directory”
    Or
    "/scratch/network/<user>" (for Adroit) or "/scratch/gpfs/<user>" (for other clusters)
  4. Click “Upload”
    1. Select “Browse files” to upload a file
    2. Navigate to the file you’d like to upload. Note you can select several
    3. Click “Upload file”
    4. Your file has now been uploaded to the directory you specified on Adroit.
    5. You can view the file by clicking on its filename in the Files interface.

NOTE: When uploading files through the OnDemand portal, each upload is limited to a size of 2 GB. If you need to upload larger files, we recommend using Linux commands, as described on our Transfer Files page. You can enter these Linux commands inside the Terminal, which you can open as described in our Running a Terminal from OnDemand section further down this page. Reach out to [email protected] if you need help with this.

Create a file (watch video)

  1. Connect to your cluster of choice via the web browser.
  2. Click “Files”
  3. Select
    “Home directory”
    Or
    "/scratch/network/<user>" (for Adroit) or "/scratch/gpfs/<user>" (for other clusters)
  4. Click “New File”
    1. Enter new file name
    2. Click “OK”
  5. Your file has been created

Edit a file (watch video)

  1. Connect to your cluster of choice via the web browser.
  2. Click “Files”
  3. Select
    “Home directory”
    Or
    "/scratch/network/<user>" (for Adroit) or "/scratch/gpfs/<user>" (for other clusters)
  4. Navigate to your file
  5. Select the menu option with 3 vertical dots and a downward facing arrow next to your file: 
rectangular button with three dots in a vertical line and an arrow head
  1. Select “Edit” from the dropdown menu that appears.
  2. You are now in the editor interface for your file. Populate it with any contents you need. Once you’re done, hit “Save” in the upper lefthand corner of the Editor interface.

Rename a file (watch video)

  1. Connect to your cluster of choice via the web browser.
  2. Click “Files”
  3. Select
    “Home directory”
    Or
    "/scratch/network/<user>" (for Adroit) or "/scratch/gpfs/<user>" (for other clusters)
  4. Navigate to your file
  5. Select the menu option with 3 vertical dots and a downward facing arrow next to your file:
rectangular button with three dots in a vertical line and an arrow head
  1. Select “Rename” from the dropdown menu that appears
  2. Enter your new filename
  3. Click “OK”
  4. Your file has now been renamed!

Copy/Move a file (watch video)

  1. Connect to your cluster of choice via the web browser.
  2. Click “Files”
  3. Select
    “Home directory”
    Or
    "/scratch/network/<user>" (for Adroit) or "/scratch/gpfs/<user>" (for other clusters)
  4. Navigate to your file
  5. Select the checkbox to the left of the file(s) you’d like to copy/move 
  6. Click the “Copy/Move” button at the top right of the Files interface
  7. Navigate to the directory you’d like to copy/move your file(s) to
  8. Click either the “Copy” or “Move” button in the dialog in the left hand portion of your screen depending on your desired operation.
  9. Your file(s) have now been copied/moved!

Delete a file (watch video)

  1. Connect to your cluster of choice via the web browser.
  2. Click “Files”
  3. Select
    “Home directory”
    Or
    "/scratch/network/<user>" (for Adroit) or "/scratch/gpfs/<user>" (for other clusters)
  4. Navigate to your file
  5. Select the menu option with 3 vertical dots and a downward facing arrow next to your file: 
rectangular button with three dots in a vertical line and an arrow head
  1. ​
  2. Select “Delete” from the dropdown menu that appears
  3. The file has now been deleted.
  4. OR: 
    1. Select the checkbox to the left of the file(s) you’d like to delete 
    2. Click “Delete” in the upper right corner of the Files interface
    3. The file(s) have now been deleted.

Download a file (watch video)

  1. Connect to your cluster of choice via the web browser.
  2. Click “Files”
  3. Select
    “Home directory”
    Or
    "/scratch/network/<user>" (for Adroit) or "/scratch/gpfs/<user>" (for other clusters)
  4. Navigate to your file
  5. Select the menu option with 3 vertical dots and a downward facing arrow next to your file: 
rectangular button with three dots in a vertical line and an arrow head
  1. ​
  2. Select “Download” from the dropdown menu that appears
  3. The file has now been downloaded to your computer!
  4. OR:
    1. Select the checkbox to the left of the file(s) you’d like to download 
    2. Click “Download” in the upper right corner of the Files interface
    3. The file(s) have now been downloaded to your computer!

Check if file storage space is full

  1. Connect to your cluster of choice via the web browser.
  2. Click “Files”
  3. Select “Quota”

Closing a session (watch video)

Running Jobs in OnDemand

To run jobs using the OnDemand interface, you need to create a slurm script for your code. To learn more about how to submit jobs to the clusters, we recommend reviewing our Guide to Princeton's Research Computing clusters.

Running a Terminal from OnDemand

To run commands on the Adroit head node, for example, browse to MyAdroit and choose "Cluster" then "Adroit Cluster Shell Access". The same applies for the other clusters with OnDemand access.

Screenshots showing where to launch a cluster shell terminal from the OnDemand interface.

Users must follow the 10-10 rule on the head node of any cluster. The 10-10 rule says that you can use up to 10% of the resources of the machine for up to 10 minutes. The head node of each cluster is shared by all users so this rule prevents someone from monopolizing the machine. The head nodes should only be used for light work such as installing software, transferring files and doing short test runs. You may be contacted by a system administrator if you fail to observe the 10-10 rule.

Working with Interactive Applications or Desktops with OnDemand

To begin an interactive session with Jupyter, RStudio, MATLAB, or Stata on our clusters, click on "Interactive Apps" in the top menu bar of your web browser. Specific intsructions for each of these programs can be found in the sections below.

When launching Jupyter, for example, you will need to click on "Interactive Apps" and then "Jupyter". You will need to choose the "Number of hours", "Number of cores" and "Memory allocated". Set "Number of cores" to 1 unless you are sure that your script has been explicitly parallelized. Click "Launch" and then when your session is ready click "Connect to Jupyter". Note that the more resources you request, the more you will have to wait for your session to become available. When your session starts, click on "New" in the upper right and choose "Python 3.7 [anaconda3/2019.10]" from the drop-down menu.

Note that Mathematica can also be used via OnDemand. If you only need a single CPU-core then consider using the Princeton Virtual Desktop which is maintained by central OIT. For more, see our Mathematica page.

Interactive Visualization Desktops

You can open interactive sessions on the visualization node of each cluster. To do so, click on "Interactive Apps" menu, and then select an option with "Desktop (Visualization Node)" or a similar name. 

Jupyter

View the Running Jupyter via Your Web Browser section on our Jupyter page for details or watch a video.

Screenshots showing where to launch a Jupyter notebook from the OnDemand interface.

RStudio

View the Running RStudio via Your Web Browser section on our R page for details or watch a video.

Screenshots showing where to launch RStudio from the OnDemand interface.

MATLAB

View the Running MATLAB via Your Web Browser section on our MATLAB page for details.

Screenshots showing where to launch MATLAB from the OnDemand interface.

Stata

View the Running Stata via Your Web Browser section on our Stata page for details.

Screenshots showing where to launch Stata from the OnDemand interface.

Close an Interactive Session

  1. Select this item in the top menu bar, next to the Interactive Sessions option:  
button with an icon of one browser square on top of another square
  1. Click the “Delete” button for the session you’d like to end.
  2. Your session has now been closed.

Finding Log Files From OnDemand Sessions

To view log files from your OnDemand Sessions:

  1. Connect to your cluster of choice via the web browser.
     
  2. Click “Files”
     
  3. Navigate to 
    /home/<your-netid>/ondemand/data/sys/dashboard/batch_connect/sys/<interactive-app-name>/output

    Be sure to insert the relevant information for the content in <>'s within the path name.

    For example, if your netid is janedoe, and you're looking for logs from your jupyter session, you would navigate to
    /home/janedoe/ondemand/data/sys/dashboard/batch_connect/sys/jupyter/output
     
  4. Navigate to the folder that has the time and date that matches the session of interest. The folder name will look something like
    e1692794-4951-4cb5-910a-2e416b7461e8
    In other words, a mess of numbers and letters.
     
  5. Within that folder, view the output.log file.