Open OnDemand Guide¶
Open OnDemand is a web-based portal that provides access to the cluster’s High-Performance Computing (HPC) resources. It allows users to manage files, submit jobs, and access graphical interfaces directly through a browser. This guide will help you understand how to access and use Open OnDemand and its associated services.
Access and Login¶
To access Open OnDemand, open a web browser and navigate to https://ood.devana.nscc.sk. On the login page, enter your username and password. Once logged in successfully, you will be prompted for a one-time password (OTP) as part of 2FA. If you haven’t set this up yet, you will be guided to do so.
2FA Problems
If you experience issues with 2FA, check your authentication method or contact system administrators for assistance.
After authentication, you'll be directed to the Open OnDemand dashboard, with the top-left side of the dashbord providing several menus that grand access to files, jobs, and your current interactive sessions.
File Explorer¶
The “Files” menu in the dashboard grants you access to your files on the cluster via a web browser. By default, the File Explorer opens to your home directory.
File Explorer Navigation¶
To navigate directories, simply click on the folder you want to open. To go back, click the up arrow. You can always see the full path of your current location above the directory listing. This shows the absolute pathname, separated by forward slashes (e.g., /home/<username>).
To quickly jump back to the top-level of your home directory, click “Home Directory”. For faster navigation, select “Change Directory” and type the absolute pathname of your desired directory (e.g., /home/<username>).
File Explorer Views¶
You can customize the File Explorer to show file permissions, ownership, and hidden files. To enable these, check the “Show Dotfiles” and “Show Owner/Mode” options at the top-right corner of the window.
File Permission
While you can view file permissions and ownership, these cannot be modified directly through the File Explorer.
Hidden Files
Hidden files, typically configuration files, are prefixed with a dot (e.g., .bashrc).
Creating, Modifying, and Deleting Files¶
You can easily create, edit, and delete files within the File Explorer.
- Creating Files: Click the “New File” button (plus icon). Enter a name and the file will be created in the current directory.
- Editing Files: To modify an existing file, select it and click “Edit” (pencil icon). This opens the Open OnDemand editor, which supports key bindings for vim or emacs, along with options for syntax highlighting, font size, and color themes.
- Renaming Files: Select the file or folder, click “Rename”, and provide a new name.
- Copying/Moving Files: Choose the file/folder, then select “Copy/Move”. Navigate to the target location and click Copy or Move.
- Deleting Files: To remove a file, select it and click “Delete”. Confirm the deletion when prompted.
Downloading and Uploading Files¶
You can easily download files from or upload files to the cluster using the File Explorer.
- Downloading: Select the files you want to download. To select multiple files, hold down Ctrl (Windows/Linux) or Command (Mac) while clicking on each file. Click the “Download” button (downward arrow) to begin the transfer. Files will be saved to your default "Downloads" folder unless specified otherwise.
File Transfer
Browsers may block multiple file downloads by default. Ensure you allow the transfer in your browser settings.
- Uploading: Click “Upload”, and drag and drop the files or browse for the files you want to upload.
Job Management¶
The “Jobs” menu in Open OnDemand includes two options: Active Jobs and Job Composer. These tools help manage and monitor jobs on the cluster.
Job Creation¶
In the Job Composer section, you can create new batch jobs to run on the cluster based on several criteria. When you first open the Job Composer, the system provides a brief introduction to its features, explaining the available options. Once you have reviewed these prompts, you can proceed by clicking “New Job” and selecting a template, path, or an existing job to base your new job on. If you close the introductory menu, you will not need to go through these prompts again.
When you create a new job using the default template, the Job Composer automatically generates a Simple Sequential Job, which consists of a job script and a job directory. You can modify the job’s options by selecting Job Options, where you can configure its name, cluster, script, and account settings. If you need to edit the job script, highlight the job, select Edit Files, and choose Edit on the job script itself. You may also rename the script if necessary. Additional files can be uploaded or created in the job’s directory using the File Explorer.
Jobs can also be created based on other templates, including both default templates and custom templates that you define within the Job Composer. Instead of using a template, you can also create a job from an existing directory by specifying a path to your home or project directory. Once selected, you can modify the job’s attributes as needed. Another option is to create a new job based on an existing job—to do this, select a job in the queue, navigate to New Job, and choose “From Selected Job”, which duplicates its configuration.
Beyond job creation, the Job Composer allows you to manage your jobs by submitting, stopping, and deleting them. Like the Active Jobs menu, the Job Composer provides filtering and sorting options, making it easy to manage multiple jobs efficiently.
Job Monitoring¶
In the Active Jobs section, you will find a structured list of your queued and running batch jobs on the cluster. The interface allows you to filter and sort jobs based on specific attributes. To sort the job list, simply click on the arrows next to the attribute headers until the list is arranged according to your preference.
For jobs that are queued or currently running, you can view detailed information directly within the Active Jobs interface. To access this information, click the right-facing arrow on the far-left of the job’s row. This will expand the job details, displaying various statistics and metadata about the job, including the Output Location, which indicates where job results and logs are stored.
Interactive Shell¶
To access an interactive shell, click on Clusters and choose from the available options. A new tab will open with the shell interface, giving you direct access to the cluster’s command line.
Interactive Applications¶
XFCE Desktop Environment¶
noVNC enables users to interact with a graphical desktop environment on the cluster directly through their web browser. This is ideal for running graphical applications, particularly those relying on X11.
noVNS Support
While most modern browsers (like Chrome, Firefox, Edge, and Safari) support noVNC, some outdated browsers may not function as expected. For optimal performance, use the latest version of one of these supported browsers.
To launch a noVNC session:
- Log in to Open OnDemand.
- In the dashboard, select “Interactive Apps” and then choose “Devana Desktop”.
- Specify the resources your application needs, such as number of nodes or cores. For most applications, a single node with one core should suffice.
- Click “Launch” to submit the session to the scheduler. Once it’s ready, click “Launch” again to access it.
When you access the session, you will see a standard Linux XFCE desktop environment. In the top-left of the GUI, the Applications menu contains links to several useful packages. In the bottom-middle of the GUI, you can open your home directory with the file cabinet icon. The black icon with a greater-than (>) symbol in it opens a terminal. If you wish to manually terminate the noVNC session, click on your username in the top-right of the GUI and select “Log Out”. Then, delete the session in Open OnDemand.
Other Applications¶
Similar to the XFCE Desktop Environment, you can launch other interactive applications through the Interactive Apps dropdown. More applications will be added in the future.
My Interactive Sessions¶
To view your current or past interactive sessions, click on My Interactive Sessions. From here, you can also launch new graphical sessions.