Open OnDemand on

Overview

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Open OnDemand is a web portal for HPC users. The Open OnDemand appliance runs this portal in one VM, connected to your OneSlurm Clusters. Users sign in with their LDAP account and, from a web browser, they can:

Manage the files in their home
Submit jobs and follow them
Open a terminal on a Cluster

The appliance is available in the OpenNebula Public Marketplace. It uses Ubuntu 26.04 LTS and Open OnDemand 4.2.

Requirements

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Before you deploy the portal, check that you have the elements in the following table.

Requirement	What the portal needs
OneSlurm Clusters	One or more Clusters in `RUNNING` state, and the IP address of each controller.
LDAP server	The LDAP server of the Clusters, with a `ldap://` URL.
NFS export	The export with the home directories of the users, for example `10.0.0.10:/export/home`.
User homes	One home directory for each user on that export, owned by the user, with mode `700`.
Virtual Network	A Virtual Network that reaches the controllers, the LDAP server and the NFS server.
OneGate	Reachable from that network. The portal publishes its URL and its errors there.

LDAP Details

Use the same domain as ONEAPP_LDAP_DOMAIN in OneSlurm. The default is slurm.local.
You can also use a base DN, such as dc=example,dc=org.
Users must be posixAccount entries under ou=People.
The portal has no bind user, so the LDAP server must allow anonymous search under ou=People.

The LDAP server of OneSlurm meets all of these points.

Quick Start

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This guide deploys the portal from Sunstone in the following steps:

Import the appliance.
Start the wizard.
Fill in the user inputs.
Attach the network of the Clusters.
Check that the portal is ready.

Step 1: Import the Appliance

In Sunstone:

Go to Storage -> Apps.
Search for Open OnDemand and select it.
Click Import and choose the image datastore.

Or, with the CLI on the Front-end:

Operations

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Use the Portal

Open the address of OOD_URL in a web browser.
Accept the certificate warning. The certificate is self-signed.
Sign in with the LDAP user name and password.

Tools for Users

Menu	Tool	What users do
Files	Home Directory	Browse, upload, download and delete files.
Jobs	Active Jobs	See their jobs on every Cluster and cancel them.
Jobs	Job Composer	Create a job from a script or a template and submit it to a Cluster.
Jobs	Project Manager	Group job scripts in project folders.
Clusters	`<name>` Shell Access	Open a terminal on the controller of a Cluster.
Clusters	System Status	See the nodes, CPUs and jobs of each Cluster.

The portal has no remote desktop, because the OneSlurm workers have no VNC server.

Troubleshooting and Limitations

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Troubleshooting

The following table lists common problems and how to solve them:

Problem	What to do
The VM shows `OOD_ERROR`	Fix the value or the service named in the message, then reboot the VM. Full log in `/var/log/one-appliance/configure.log`.
The browser does not open the portal	Check that the VM shows `READY=YES` and that your network reaches the IP of `OOD_URL` on port 443. Logs: `journalctl -u apache2 -u ondemand-dex`.
Login fails with the right password	The user is not under `ou=People`, or LDAP does not answer. Test in the VM with `ldapsearch -x -H <URL> -b ou=People,<base DN> uid=<user>`. For `slurm.local`, the base DN is `dc=slurm,dc=local`.
Home directory not found	Create the home directory of the user, then click Restart Web Server on that page.
Active Jobs is empty, or `Permission denied` in Submit or the terminal	Click Help -> Restart Web Server. This adds the key of the user to `~/.ssh/authorized_keys` again. Logs: `journalctl -t ood-prehook`.
System Status shows an error page	A controller does not answer. That Cluster shows no jobs, and the Job Composer and the terminal show an SSH error. Everything works again when the controller is back.
Pages load forever with no message	The NFS server does not answer. The portal works again by itself when NFS is back. Meanwhile, use the VM console in Sunstone, because SSH to the VM can also hang.

Known Limitations

Area	Limitation	What to do
Files	Uploads are limited to 256 MiB.	Copy bigger files with `scp` or `rsync` to a Cluster controller, which has the same home.
Terminal	The terminal closes when the page reloads.	Run long work under `tmux` or `screen` on the controller.
Job Composer	If the first visit is a direct link to `/pun/sys/myjobs/`, it creates an empty database and shows error 500 from then on.	Open it the first time from the Jobs menu. To fix it, delete `~/ondemand/data/sys/myjobs/production.sqlite3` of that user (only if the file has no tables) and open the Job Composer from the menu.
Job Composer	New Job -> From Template creates a job without a script.	Open Job Options, select the script and click Save.
Job states	OneSlurm has no Slurm accounting, so a cancelled job shows `Completed` in Active Jobs and `Failed` in the Job Composer.	Check the real state with `scontrol show job <ID>` or in the output file of the job.
Project Manager	Deleting a project only removes it from the list. The files stay.	Delete the files in Files.
Two portals	With two portals on the same homes, the Job Composer fails with error 500 when a user opens it on both at the same time.	Use one portal for each NFS home export.
New Clusters	A new Cluster needs a running controller. If it does not answer, the configuration stops with `OOD_ERROR`.	Start the controller first. Clusters the portal already knows can be stopped for maintenance.