BROWSER-BASED HPC · FILES · JOBS · INTERACTIVE APPS

Open OnDemand on Deceema¶

Move from idea to computation without leaving your browser. Open OnDemand gives you a visual gateway to Deceema files, command-line tools, Slurm jobs, and interactive research applications—all backed by the same projects, storage, and compute resources you use from the terminal.

Launch your first session Learn the interface

Your view may be different

Open OnDemand is configured for each HPC environment. The menus, applications, launch fields, and session controls visible on Deceema may vary according to platform configuration and your project access. Follow the labels shown in your portal when they differ from the examples here.

HPC Power, Browser Simplicity¶

Open OnDemand does not replace Deceema or Slurm. It presents familiar HPC capabilities through a web interface: a file action still affects your Deceema storage, a submitted job still enters the Slurm queue, and an interactive application still consumes allocated compute resources.

Files

Browse directories, upload or download modest files, create folders, and edit small text files where enabled.
Shell

Open a browser terminal for file preparation, environment checks, and Slurm commands.
Jobs

Submit or inspect scheduled work through available job tools while Slurm remains the source of truth.
Interactive Apps

Request resources and connect to enabled tools such as notebooks, desktops, or graphical research applications.

Choose the Right Way to Work¶

Need	Best starting point	Why
Browse, rename, or inspect a few files	Open OnDemand Files	A quick visual view of accessible storage.
Make a small configuration edit	Files editor or Shell	Fast for lightweight text changes.
Explore data in a notebook or GUI	Interactive App	Provides browser access to a scheduled compute session.
Run a long or repeatable analysis	Slurm batch job	Reproducible, unattended, and easier to audit.
Move a large dataset	Approved transfer workflow	More resilient and efficient than a browser upload.
Automate many files or jobs	Shell plus Slurm	Scripts make the workflow repeatable and scalable.

Open OnDemand makes HPC approachable, but good HPC habits still matter. Use interactive sessions for active exploration and batch jobs for production work that should continue without an open browser.

You should have:

an active Deceema account;
the Open OnDemand address supplied by your organization;
a Deceema project code and its corresponding QoS;
permission to use the application you need; and
input data in an accessible Deceema storage location.

Confirm the project and QoS pairing from your Deceema access approval or account details in Deceema Admin. If the project, QoS, or application you expect is missing, do not guess a replacement. Review Requesting Access or contact Support.

Protect your session

Never share your password, multi-factor code, private key, access token, browser cookie, or active session link. Sign out on shared devices and do not ask another person to work through your authenticated browser session.

Find Your Way Around¶

The exact navigation can be customized, but an Open OnDemand dashboard may offer some of the following areas:

Area	Use it to	Remember
Dashboard	Read announcements and find commonly used apps.	Check notices before starting important work.
Files	Browse enabled Deceema paths and perform basic file actions.	Permissions and storage policies still apply.
Clusters / Shell Access	Open a terminal connected to a configured cluster.	A shell commonly starts on a login node, not an allocated compute node.
Jobs / Active Jobs	View or manage Slurm work.	Save the job ID and verify details with Slurm when needed.
Job Composer	Create and submit batch jobs through a guided interface, if enabled.	Review the generated script and resource request before submission.
Interactive Apps	Launch enabled browser-based applications.	Each session is a scheduled job using shared resources.
My Interactive Sessions	Find queued, running, or completed session cards.	Return here to reconnect, stop, or diagnose a session.

Applications may also be pinned to the dashboard or grouped under an app catalog. A missing menu does not necessarily indicate an outage—it may not be enabled for the deployment or your account.

Launch Your First Interactive Session¶

The launch form translates your choices into a Slurm request. Treat it with the same care as a batch script.

1. Open the application¶

Sign in using the approved Deceema Open OnDemand address. Choose Interactive Apps, All Apps, or a pinned application, then select the tool you need.

Examples can include Jupyter, RStudio, a remote desktop, or a specialist scientific application. Availability is determined by the Deceema catalog and your access; an example here is not a promise that an app is installed.

2. Complete the launch form¶

The form may request some or all of these values:

Field	What it controls	Beginner guidance
Project / account	Which Deceema allocation owns the work.	Select a project included in your approved access.
QoS	The scheduling policy permitted for that project.	Keep the project/QoS pair together.
Run time	The maximum duration of the session.	Allow enough time to work and save, but avoid a needlessly large request.
Tasks / CPU cores	Processing capacity allocated to the app.	Start with the application's documented minimum and scale from evidence.
Memory	Working memory available to the session.	Increase only when the workload or prior measurements justify it.
GPU	Accelerator resources, when offered.	Request one only for GPU-enabled software and workloads.
Working directory	The initial project or data location.	Use an existing path you can read and write.
Software version	The application environment to start.	Record the selected version with your research notes.

A bigger request is not automatically faster

Large CPU, memory, GPU, or time requests can wait longer for suitable resources. The application must also be configured to use what you request. Start small, measure, and right-size the next session.

3. Launch once¶

Review the values, then submit the form once. Open My Interactive Sessions to follow the new session card.

Do not create duplicates because a session is waiting. A valid request may be queued until suitable resources become available.

4. Connect when ready¶

When the card reports that the application is ready, select its connection button. The label may be Connect, Launch, Open, or something application-specific.

Confirm the application and input path before beginning expensive work. Save a small test output early so you know the destination is writable.

5. Save and finish deliberately¶

Save results to persistent Deceema storage before the requested time expires. When finished, close the application cleanly and use the available session control to stop or cancel the allocation.

Closing the tab may not stop the job

A browser tab is only your view of the session. Closing it can leave the interactive job running. Check My Interactive Sessions and, when needed, squeue --user="$USER" to confirm that resources were released.

Understand Session States¶

Labels differ by application and configuration, but this mental model is reliable:

Submitted → Queued → Starting → Ready/Running → Completed
                         ↘ Failed

Stage	What is happening	What to do
Submitted	Open OnDemand has created the session request.	Confirm there is only one intended session.
Queued / Pending	Slurm accepted the job and is waiting for a scheduling condition.	Inspect the request and wait; do not submit duplicates.
Starting	Resources were allocated and the application is initializing.	Allow startup to finish and watch the card for a connection action.
Ready / Running	The application is available or executing.	Connect, work, and save frequently.
Completed	The Slurm job ended or was stopped.	Verify results before removing any session record.
Failed	Submission, startup, connection, or application execution failed.	Preserve the session ID, job ID, and useful error details.

The session card may show a session ID as well as a Slurm job ID. Keep both when troubleshooting: they identify different layers of the workflow.

Work with Files Confidently¶

Open OnDemand's Files interface can make everyday storage tasks quicker. Depending on the enabled controls, you may be able to:

navigate permitted home and project directories;
create a directory;
upload or download modest files;
rename, move, copy, or delete selected items;
edit a small text file; and
open a shell at the displayed location.

Know exactly where you are¶

Paths, permissions, and ownership are the same concepts you encounter in a terminal. Before changing data, confirm the full path and selected items.

$ pwd
$ ls -ld PATH

Use the right transfer method¶

Browser transfer is convenient for a small number of modest files. For large datasets, unreliable connections, or repeatable transfers, use the approved Deceema data-transfer method described in Storage.

Treat delete as delete¶

Do not assume every Files action has a recoverable trash or undo step. Verify the path, selection, and backup before deleting or overwriting important data.

Avoid exposing secrets¶

Do not store passwords, private keys, tokens, or credentials in notebooks, scripts, shared directories, screenshots, or uploaded configuration files.

Use the Browser Shell Wisely¶

The Shell app gives you a terminal in the browser. It is useful for:

navigating and inspecting files;
editing scripts and configuration;
loading modules and checking software versions;
submitting and monitoring Slurm jobs; and
performing short, lightweight preparation tasks.

$ hostname
$ squeue --user="$USER"

The browser shell does not turn a login node into a compute node. Submit substantial CPU, memory, GPU, or long-running work through Slurm. If the browser disconnects, commands tied to that terminal may not behave as you expect; use a batch job for work that must be durable and unattended.

Start the Slurm tutorial

Work with Jobs¶

If Active Jobs or Job Composer is enabled, it offers a visual route into Slurm. The same principles apply whether you click a button or type sbatch:

use the correct account and QoS pair;
request realistic CPU, memory, GPU, and wall time;
create output directories before the job runs;
save the returned job ID;
inspect pending reasons before resubmitting; and
verify application output, not only the scheduler state.

For detailed job control, the shell remains useful:

$ squeue --jobs=JOB_ID
$ scontrol show job JOB_ID
$ sacct --jobs=JOB_ID --format=JobID,JobName,State,ExitCode,Elapsed
$ scancel JOB_ID

Before cancelling, confirm the exact job ID. Open OnDemand sessions are Slurm jobs too, so terminal-side job actions can affect a browser application.

Build a Reliable Interactive Workflow¶

Interactive discovery becomes reproducible research when you preserve the decisions behind it:

Begin with a small representative input.
Record the application and version.
Record project, QoS, time, CPUs, memory, and GPU choices.
Keep source data separate from generated results.
Save commands, notebook cells, parameters, and environment information.
Export or save results to durable storage throughout the session.
Move mature, repeatable computation into a script and Slurm batch job.
Verify the output before stopping the session or removing its record.

Use interactive work to discover; use batch work to reproduce

Explore until the method is clear, then capture it in code with explicit inputs, outputs, software, and resource requirements.

Troubleshoot Methodically¶

I cannot sign in

Confirm that your Deceema account is active and that you are using the approved Open OnDemand address. Record the exact error, date, time, and time zone. Never send your password, multi-factor code, or private key.

A menu or application is missing

Confirm the expected project against your approved access. The application may not be enabled, may be restricted to a project, or may appear under All Apps rather than the dashboard. Report the app name and expected access.

My session stays queued

A queued session may be valid and waiting for resources. Record the session ID and job ID, then inspect squeue --jobs=JOB_ID and its reason. Check the account/QoS pair and right-size the resource request before considering a retry.

My session fails while starting

Preserve the session card and record the complete visible error, session ID, job ID, app, launch time, account, QoS, and requested resources. Check Service Status before submitting a support request.

The connection button appears, but the app will not open

Try the button from the existing session card instead of launching another session. Record the browser and version, visible message, and whether a private browsing window behaves differently. Do not share the session URL if it contains connection credentials or tokens.

My browser disconnected

Return to My Interactive Sessions. If the session is still running, reconnect using its card. If it completed, inspect the final state and saved output before starting another session.

My files are missing or read-only

Confirm the exact path, project membership, and permissions from both the Files interface and shell. Do not change permissions blindly. Follow the Storage troubleshooting guide if the path behaves unexpectedly.

The application ran out of time or memory

Inspect the Slurm state and application output. Use completed-run evidence to request a justified amount next time; do not jump automatically to the largest available values.

Send a Useful Support Request¶

Capture this information before deleting a failed session card:

Open OnDemand support details

Deceema username:
Project code and QoS:
Open OnDemand application:
Application version, if shown:
Session ID:
Slurm job ID:
Launch date, time, and time zone:
Requested time, CPUs, memory, and GPUs:
Working directory, if relevant:
Browser and version:
Expected result:
Actual result:
Complete visible error:
Smallest steps that reproduce the issue:
Checks already completed:

Open OnDemand keeps per-session diagnostic data, but those files can include connection details or tokens. Do not attach an entire raw session directory or log blindly. Share only the smallest sanitized excerpt requested through the approved support channel.

Open Support Check Service Status

First-Session Challenge¶

Complete this small exercise to build confidence:

Sign in and identify the Files, Shell, Interactive Apps, and My Interactive Sessions areas available to you.
Use Files to create a disposable training directory in an appropriate location.
Open Shell and confirm the directory's full path.
Launch the smallest suitable interactive session with the correct project and QoS.
Save a text file from the application into the training directory.
Reconnect once from My Interactive Sessions.
Stop the session and confirm its Slurm job no longer consumes resources.
Verify the saved file from Files or Shell.

Success means more than opening an application: you can connect the browser, scheduler, storage, and session lifecycle into one deliberate workflow.

Open OnDemand Readiness Checklist¶

I use only the approved Deceema Open OnDemand address.
I understand that menus and apps depend on configuration and access.
I can match a project with its permitted QoS.
I know that an interactive session is a scheduled Slurm job.
I can tell the difference between closing a tab and stopping a session.
I save important output to persistent storage before time expires.
I use approved transfer methods for large datasets.
I preserve session and job IDs when troubleshooting.
I move mature, unattended workflows to batch jobs.

Official Open OnDemand Resources¶

These external references open in a new tab: