UCloud Developer Guide

UCloud is a digital research environment. It provides an intuitive user interface that improves the usability HPC environments or other computing environments such as Kubernetes clusters. UCloud provides a way to access and run applications regardless of users’ location and devices. It also serves as a cloud data storage, which allows users to analyse and share their data.

End-Users: Documentation

If you are a user and just want to know how to use UCloud, check out our getting started guide.

Application Developers: Getting Started

Interested in developing applications for UCloud? We have the guide for you here.

UCloud Developers: Getting Started

Our getting started guide for backend developers is located here. You can read more about the frontend here.

You might also be interested in our general procedures, deployment checklists and CI/CD system.

Release Notes

Internal release notes can be found here.


UCloud provides storage resources to users in the form of a file system. This file system provides familiar operations on data to end-users. The file system allows, e.g., users to read and write folders and files. Access to the file system is provided through a common API interface which enforces data management constraints and auditing. The storage service is responsible for storage.

UCloud offers a variety of features built on top of the storage, including:


Users are able to share the files they own with other users. When sharing a file, the owner specifies whether the receiving user only can view the file or if he/she is able to edit the file as well. If the receiving user chooses to accept the share, the file will be available in her/his home folder with the correct permissions. The owner of the file can also revoke a share. When revoking a shared file, the system automatically removes all permissions to the receiver and the file will not be accessible anymore.

UCloud provides the possibility to create projects for research collaborations between users. When a project is created, the system creates a shared file system among the specified collaborators. The shared file system is separate from the users normal file system. To use the project specific file system the user will have to switch context to their project. This mechanism enforces a clear division between a users own files and those that belong to the project.


UCloud presents a collection of software packages to the users in the “Apps” tab of the web app. The apps can be executed in batch (headless) mode or interactive mode. The web GUI allows user to run apps on a supported backend (HPC slurm, K8s). Applications are handled via the app store service and the app orchestrator service. More computational backend can be supported (e.g. OpenStack, commercial clouds).

Each app in UCloud is associated to a “tool” (e.g. Docker image) and gives the user the ability to run a specific command of the tool.

An app can use the files that are already located in UCloud as input data. Folders can be made available read only or read/write. Each app is executed in a root “work” folder, into which other folders from UCloud are mounted. Once an app has finished, the output files in the “work” folder are available in the UCloud file system.

Just as with the storage, UCloud keeps an account of the compute time used. A user can see, via the web app, how much compute time they have used on UCloud for any given time period. Again, it is possible to create reports if billing is needed.

Both tools and apps are defined via YAML documents. The tools describes which container image should be used by the apps associated to the tool. The app YAML document describes how the tool should be invoked and the necessary parameters. For more details on the tool and app format see: