Project goal

CERN’s cloud infrastructure is among the world’s largest private OpenStack installations. CERN and Huawei therefore have a common interest in driving and enhancing the development of OpenStack for large-scale applications. Work on this project is being carried out through the community processes of OpenStack, with the results being made fully open source.

R&D topic
R&D Topic 1: Data-centre technologies and infrastructures
Project coordinator(s)
Tim Bell
Technical team members
Theodoros Tsioutsias, Surya Seetharaman
Collaborator liaison(s)
Stephan Keuneke


Project background

It is important to ensure that the management system used for allocating CERN’s computing resources is as efficient as possible and enables scientists to gain access to resources on a simple, self-service basis. By running common software based on OpenStack — both in on-premises and commercial clouds — we can meet the end users’ needs for LHC Run 3 and beyond in an efficient and seamless manner. The enhancements we make will be submitted upstream and included in future releases of OpenStack, meaning that they will be available for use both in CERN’s private, on-premises cloud and in products from Huawei based on OpenStack.

Recent progress

There are two main areas of focus for this project, namely OpenStack Cells v2 and pre-emptible instances.

Cells provides a way to build large clouds out of pools of resources; an initial implementation of this has been used at CERN since the in-house cloud went into production in 2013. The OpenStack community has developed a new version, Cells v2, which is now the default for all OpenStack clouds. It was put into production at CERN in 2018. We have worked closely with the upstream developers to design the solution, validate it at scale, and enhance the code — based on the experience we have gained.

The use of pre-emptible instances in OpenStack makes it possible for users to create virtual machines that can be rapidly stopped if higher priority work arrives, thus enabling

CERN’s computing resources to be managed more efficiently. The design has been approved by the OpenStack community and prototyped at CERN.

Next steps

The enhancements for Cells v2 are now included in the upstream OpenStack package, with the pre-emptible instances soon due to go into use on the production cloud. This will complete the deliverables for the project in 2019.


    T. Bell, OpenStack at scale (20 March), Presented at CeBit 2017, Hannover, 2017.
    V. E. Araujo Soto, Application Catalog for Openstack (15 August), Presented at CERN openlab summer students’ lightning talks, Geneva,
    J. van Eldik, Clouds at CERN (5 September), Presented at Huawei Connect, Shanghai, 2017.
    T. Bell, Huawei OpenStack Clouds (21 Seprember), Presented at CERN openlab Open Day, Geneva, 2017.
    T. Bell, Clouds at CERN (26 September), Presented at OpenStack days UK, London, 2017.
    T. Bell, Clouds at CERN (26 October), Presented at Huawei Connect Europe, Berlin, 2017.
    B. Moreira, Moving from CellsV1 to CellsV2 at CERN (21 May). Presented at OpenStack Summit, Vancouver, 2018.
    B. Moreira, Containers on Baremetal and preemptible VMs at CERN and SKA (24 May). Presented at OpenStack Summit, Vancouver, 2018.
    B. Moreira, Optimisations OpenStack Nova for Scientific Workloads (10 July). Presented at 23rd International Conference on Computing in High Energy and Nuclear Physics (CHEP), Sofia, 2018.
    B. Moreira, S. Seetharaman, Scaling Nova with Cells V2 (13 November). Presented at OpenStack Summit, Berlin, 2018.
    T. Tsioutsias, Pre-emptible instances and bare metal containers (15 November). Presented at OpenStack Summit, Berlin, 2018.