Evolution of the CERNBox platform to support the Malt project

Evolution of the CERNBox platform to support the Malt

project

Hugo González Labrador

1, ∗

, Vincent Nicolas Bippus

, Sebastian Bukowiec

, Diogo Castro

Sebastien Dellabella

, Michal Kwiatek

, Giuseppe Lo Presti

, Luca Mascetti

, Jakub T.

scicki

, Esteban Puentes

, Piotr Jan Seweryn

, Apostolos Smyrnakis

CERN, 1 Esplanade des Particules, Meyrin, Switzerland

Abstract.

CERNBox is the CERN cloud storage hub for more than 25,000 users at CERN.

It allows synchronising and sharing ﬁles on all major desktop and mobile plat-

forms (Linux, Windows, MacOSX, Android, iOS) providing universal, ubiq-

uitous, online- and oﬄine access to any data stored in the CERN EOS infras-

tructure. CERNBox also provides integration with other CERN services for big

science: visualisation tools, interactive data analysis and real-time collaborative

editing.

Over the last two years, CERNBox has evolved from a pure cloud sync and

share platform into a collaborative service, to support new applications such

as DrawIO for diagrams and organigrams sketching, OnlyOﬃce and Collabora

Online for documents editing, and DXHTML Gantt for project management, as

alternatives to traditional desktop applications. Moving to open source applica-

tions has the advantage to reduce licensing costs and enables easier integration

within the CERN infrastructure. This move from commercial software to open

source solutions is part of the MALT project, led by the IT department at CERN

to reduce the dependencies on commercial solutions.

As part of the MALT project, CERNBox is the chosen solution to replace

Home directories of the Windows DFS ﬁle system. Access to storage from

Windows managed devices for end-users is largely covered by synchronization

clients. However, online access using standard CIFS/SMB protocol is required

for shared use-cases, such as central login services (Terminal Services) and vis-

itor desktop computers. We present recent work to introduce a set of Samba

gateways running in High Availability cluster mode to enable direct access to

the CERNBox backend storage (EOS).

1 Introduction

The background of the MALT project was provided in CERN Computing Newsletter [1]:

Over the years, CERN’s activities and services have increasingly relied on com-

mercial software and solutions to deliver core functionalities, often leveraged by

advantageous ﬁnancial conditions based on the recognition of CERN’s status as

an academic, non-proﬁt or research institute.

∗

e-mail: [email protected]

Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).

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Given the collaborative nature of CERN and its wide community, a high number

of licenses are required to deliver services to everyone, and when traditional

business models on a per-user basis are applied, the costs per product can be

huge and become unaﬀordable in the long term.

The initial objective of the MALT project is to investigate the migration from commercial

software products to open-source solutions. The project also helps to minimise the exposure

of CERN to the risks of unsustainable commercial conditions. By doing so, the laboratory

is playing the pioneering role among public research institutions, especially in Europe, most

of which have recently been faced with the same dilemma as well as questions about Digital

Sovereignty.

The IT Storage group participates actively in this important project exposing alternatives

to commercial software to the CERNBox[3–5] user community (more than 25,000 user ac-

counts).

2 CERNBox

The CERN IT Storage group is responsible for ensuring a coherent development and opera-

tion of the storage services at CERN for all aspects of physics data. The group supports the

data requirements for the experiments at CERN and as well as supporting storage services

for the whole CERN users community (CERNBox and AFS).

CERNBox is the CERN cloud storage hub and has become one of de facto platforms for

collaboration at CERN. CERNBox was launched 2014 to address the necessity of oﬀering an

easy and convenient way to access and share the physics data. It was also introduced to better

protect the data of the organization by ensuring clear data protection policies (all CERNBox

data is stored on CERN premises) and clear data management policies.

The goal with CERNBox is to consolidate diﬀerent home directory use-cases (DFS for

Windows users and AFS for Linux users) into only one service that can be accessed from any

platform satisfying most of the requirements of the systems currently running.

Figure 1: How to access CERNBox

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CERNBox is based on two open source components: ownCloud[2] and EOS[16, 17].

ownCloud is an open source cloud collaboration software and EOS is CERN open source

elastic, adaptable and scalable storage system for storing the data generated by the LHC.

Users can connect to CERNBox using various methods as depicted in Figure 1:

• FUSE access: EOS storage can be mounted as a local ﬁle-system. This is important for

computers inside the computer centre that do not have graphical interfaces and need to

perform batch job processing. Also, many analysis tools are not adapted to work with

remote storage systems and they expect a local ﬁlesystem.

• WebDAV: the storage is accessible through WebDAV enabled clients like Finder for OSX,

Windows Network Drives for Windows or third-party tools like CyberDuck, which brings

a user-friendly access methods to end-users.

• XROOTD: the storage can also be accessed by using the xrootd high performance, scalable

and fault tolerant access protocol.

• Synchronization client: this is a component, integrated in the user desktop environment,

which keeps one (or more) local folders in synchronization with the central storage server.

Users can work on their devices without connectivity and the synchronization client recon-

ciles changes when the network connectivity is restored. This component enables users to

work oﬄine.

• Web access: via any web browser the user can manipulate ﬁles and share them with other

users. Users can also take advantage of the available applications in CERNBox to work

with certain ﬁle types. See section 3 for more information on the applications.

• Mobile devices: CERNBox provides mobile and tablet applications for Android and iOS

to access the data.

• Samba (SMB) access: CERNBox provides online access via the SMB/CIFS networking

protocol, used mainly by Windows clients. SMB support was added due to the increasing

demand for online access from Windows client, following the ongoing migration from DFS

to CERNBox. Refer to sections 4 and 5 for more details.

3 MALT Applications

CERNBox oﬀers a convenient and universal (browser-based) access to a collection of useful

applications, designed to boost the productivity of our user community. Users can just use

these applications without having to install any software on their computers. A web browser

is the only tool needed to access a catalog of diverse applications, ranging from basic text

editors to complex and high performance web based software analysis platforms such as

SWAN[18]. In this section we explore a variety of applications in close relationship with the

MALT objectives: replacing commercial applications with open source alternatives.

Editing of Microsoft Oﬃce documents has been available in CERNBox for a number of

years using integration with SharePoint. This enabled our user community to view and edit

documents online, both standalone and to a certain extent in a collaborative fashion.

In an attempt to improve collaborative edition, as well as to identify suitable alternatives

in the market, we are proposing to our user community other similar products. OnlyOﬃce is

a cloud-oriented solution with a modern and intuitive user interface allowing multiple people

to collaborate on documents, spreadsheets and presentations [11]. Currently, we are ﬁnishing

our testing phase using Canary Testing Mode, a feature ﬂag mechanism of CERNBox which

allows to expose volunteer users to new applications.

At the moment, OnlyOﬃce is deployed as a single container application running on a

bare metal server. This has been largely suﬃcient for the testing phase, where the number

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of concurrent users has never exceeded some tens. However, for the long term operations

and scalability of the new service, we are planning to use our Puppet-managed infrastructure

on top of OpenStack. Following vendor’s deployment recommendations, the initial plan

includes installation of two front-end OnlyOﬃce Document Servers in a high-availability

conﬁguration, as well as other required back-end services on separate VMs.

In addition to OnlyOﬃce, Collabora Online [12] also oﬀers a cloud-based service specif-

ically optimized for the Open Data ﬁle formats. After an initial successful proof-of-concept

integration in CERNBox, we plan to prototype its integration in the near future.

As far as other oﬃce productivity applications are concerned, Gantt Chart Viewer is an

application designed for users who just need to view Gantt charts [10]. Draw.io is an applica-

tion that allows opening and creating diﬀerent types of diagrams [13]. Both applications were

integrated in CERNBox using dedicated integration applications based on the work available

at [15]. The diagram presented in Figure 2 describes the data ﬂow between these tools and

CERNBox. Once the user logs in and opens a ﬁle, the integration application creates an

iframe and loads a particular tool by setting its URL. The ﬁle data is transferred using the

window.postMessage API, part of the HTML5 standard. Integration uses the client.js library

for obtaining the ﬁles’ content either as a text or an array buﬀer. Finally, both applications

depend on micro services hosted on-site for importing and exporting ﬁles in diﬀerent formats,

which allows us to keep our users’ data on premise.

Figure 2: Integration of Gantt Chart Viewer and Draw.io with CERNBox.

4 SMB Access to CERNBox

With the increased demand of online access to the CERNBox backend storage (EOS) from

Windows, a cluster of SMB/CIFS gateways has become critical. To this end, in order to

provide a High Available (HA) setup, the Samba and CTDB software suites [14] have been

deployed on a cluster of four nodes with an IP-based load balancing over ﬂoating IPs, as re-

quired by the software. The cluster is in production since September 2019, and it permanently

serves several hundreds Windows clients in the CERN network.

This cluster is instrumental to perform the ongoing mass migration of CERN Windows-

based users from DFS to CERNBox, as detailed in the following section.

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5 DFS Migration to CERNBox

In the context of the MALT project, the CERN users’ Windows Home directories are being

migrated from the Distributed File System (DFS) into CERNBox. The devised procedure

involves the following three steps:

• Communication with the user

• Provisioning of a CERNBox home and data/metadata copy

• Conﬁguration of end-user computer(s) to switch to CERNBox

5.1 Communication with the user

Communicating with users is of essential importance: the DFS team contacts the users one

week before the migration to provide them with all the necessary information and instructions

for the procedure. The users are given the option to postpone the intervention in case they

have important work constraints on the suggested date. The most important action points in

this communication are two:

1. Users need to save their work and do not access their ﬁles during the migration time-

window

2. The DFS Home folder will be read-only after the migration

5.2 CERNBox home provisioning and data copy

An overnight automated procedure is provisioning a new Home directory in CERNBox, cre-

ating also the necessary folder layout structure to accommodate the typical folders found on

a Windows system:

• Documents (from DFS “Documents” folder, excluding the sub-directories My Music, My

Pictures and My Video)

• Music (from the DFS “Documents/My Music” folder)

• Pictures (from the DFS “Documents/My Pictures” folder)

• Videos (from the DFS “Documents/My Video” folder)

• WINDOWS/Desktop (from the DFS “Desktop” folder)

• WINDOWS/Favorites (from the DFS “Favorites” folder)

Under no circumstances this automated procedure overwrites or deletes existing data.

Files and folders are already safely copied in CERNBox. In the case the user had a CERNBox

space already, the script checks for name clashes; in case they exists, the migration procedure

will not start. To copy the data from DFS to CERNBox, a server side copy procedure is

implemented. Before the selected migration date, data is copied transparently from DFS to

CERNBox progressively, using the rsync tool.

5.3 Final conﬁguration on end-user computer(s)

Once users log into their computers, a script is automatically run to conﬁgure their machines

to switch from DFS to CERNBox. The script identiﬁes the main user of the computer and

applies one of the following conﬁgurations depending on the device:

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1. Conﬁguration of the CERNBox sync client to store data locally: directories listed

above are saved locally in the Hard Drive. The CERNBox client will use the local

cernbox path to synchronize its content with the server. The Windows Registry is

then conﬁgured accordingly for the typical Windows folders (refer to Section 5.2).

2. Conﬁguration of a network mapped drive using the SMB protocol: in this case, data

is not stored locally. A network drive is created pointing to the SMB gateway for

CERNBox and the Windows Registry is updated to point to the corresponding remote

folders. This conﬁguration is suggested for shared computers (e.g. meeting room PCs)

where having the client synchronising the proﬁle of many users would not be optimal

and could result in ﬁlling up the Hard Drive quickly.

6 Outlook

We plan to introduce more application integrations with alternative open source solutions,

as discussed in section 3, to reduce our dependencies on existing commercial software. The

usage and easy of adoption of these alternative products will be monitored during the coming

years. At the same time, we aim at increasing the productivity of our users in their daily

workﬂows, in particular when it comes to uploading and downloading ﬁles from diﬀerent

clouds: for example, many users use the Overleaf platform to edit LaTeX documents to

prepare scientiﬁc papers, and the data to prepare them typically is already in CERNBox. We

are also exploring a concept we name Bring Your Own Application, to eﬃciently allow users

and developers to connect their preferred applications to CERNBox (refer to [9] for a more

detailed explanation) using the micro-services deployment pattern [6, 7].

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