# Distributed Applications and Interoperable Systems

Miguel Matos, Fabíola Greve

► To cite this version:

Miguel Matos, Fabíola Greve. Distributed Applications and Interoperable Systems: 21st IFIP WG 6.1 International Conference, DAIS 2021, Held as Part of the 16th International Federated Conference on Distributed Computing Techniques, DisCoTec 2021, Valletta, Malta, June 14–18, 2021, Proceedings. Springer International Publishing, LNCS-12718, 2021, Lecture Notes in Computer Science, 978-3-030-78197-2. 10.1007/978-3-030-78198-9. hal-03384850

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Founding Editors

Gerhard Goos

Karlsruhe Institute of Technology, Karlsruhe, Germany

Juris Hartmanis

Cornell University, Ithaca, NY, USA

Editorial Board Members

Elisa Bertino

Purdue University, West Lafayette, IN, USA

Wen Gao

Peking University, Beijing, China

Bernhard Steffen

TU Dortmund University, Dortmund, Germany

Gerhard Woeginger

RWTH Aachen, Aachen, Germany

Moti Yung

Columbia University, New York, NY, USA
More information about this subseries at http://www.springer.com/series/7411
Miguel Matos · Fabíola Greve (Eds.)

# Distributed Applications and Interoperable Systems

21st IFIP WG 6.1 International Conference, DAIS 2021

Held as Part of the 16th International Federated Conference
on Distributed Computing Techniques, DisCoTec 2021

Valletta, Malta, June 14–18, 2021

Proceedings

<figure><img src="image_2.png" /></figure>

Springer
Editors

Miguel Matos

University of Lisbon
Lisbon, Portugal

Fabiola Greve

Federal University of Bahia
Salvador, Brazil

ISSN 0302-9743

ISSN 1611-3349 (electronic)

Lecture Notes in Computer Science

ISBN 978-3-030-78197-2

ISBN 978-3-030-78198-9 (eBook)

https://doi.org/10.1007/978-3-030-78198-9

LNCS Sublibrary: SL5 – Computer Communication Networks and Telecommunications

© IFIP International Federation for Information Processing 2021

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# Foreword

The 16th International Federated Conference on Distributed Computing Techniques (DisCoTec 2021) took place during June 14–18, 2021. It was organised by the Department of Computer Science at the University of Malta, but was held online due to the abnormal circumstances worldwide affecting physical travel. The DisCoTec series is one of the major events sponsored by the International Federation for Information Processing (IFIP), the European Association for Programming Languages and Systems (EAPLS), and the Microservices Community. It comprises three conferences:

- *COORDINATION*, the IFIP WG 6.1 23rd International Conference on Coordination Models and Languages;

- *DAIS*, the IFIP WG 6.1 21st International Conference on Distributed Applications and Interoperable Systems;

- *FORTE*, the IFIP WG 6.1 41st International Conference on Formal Techniques for Distributed Objects, Components, and Systems.

Together, these conferences cover a broad spectrum of distributed computing subjects, ranging from theoretical foundations and formal description techniques, to systems research issues. As is customary, the event also included several plenary sessions in addition to the individual sessions of each conference, which gathered attendants from the three conferences. These included joint invited speaker sessions and a joint session for the best papers from the respective three conferences. Associated with the federated event, four satellite events took place:

- *DisCoTec Tools*, a tutorial session promoting mature tools in the field of distributed computing;

- *ICE*, the 14th International Workshop on Interaction and Concurrency Experience;

- *FOCODILE*, the 2nd International Workshop on Foundations of Consensus and Distributed Ledgers;

- *REMV*, the 1st Robotics, Electronics, and Machine Vision Workshop.

I would like to thank the Program Committee chairs of the different events for their help and cooperation during the preparation of the conference, and the Steering Committee and Advisory Boards of DisCoTec and its conferences for their guidance and support. The organization of DisCoTec 2021 was only possible thanks to the dedicated work of the Organizing Committee, including Caroline Caruana and Jasmine Xuereb (publicity chairs), Duncan Paul Attard and Christian Bartolo Burlo (workshop chairs), Lucienne Bugeja (logistics and finances), and all the students and colleagues who volunteered their time to help. I would also like to thank the invited speakers for their excellent talks. Finally, I would like to thank IFIP WG 6.1, EAPLS, and the Microservices Community for sponsoring this event, Springer’s Lecture Notes in
Computer Science team for their support and sponsorship, EasyChair for providing the
reviewing framework, and the University of Malta for providing the support and
infrastructure to host the event.

June 2021

Adrian Francalanza
Preface

This volume contains the papers presented at the 21st IFIP International Conference on Distributed Applications and Interoperable Systems (DAIS 2021), sponsored by the International Federation for Information Processing (IFIP) and organized by the IFIP WG 6.1. The DAIS conference series addresses all practical and conceptual aspects of distributed applications, including their design, modeling, implementation, and operation, the supporting middleware, appropriate software engineering methodologies and tools, and experimental studies and applications. DAIS 2021 was meant to be held during June 14–18, 2021, in Valletta, Malta, as part of DisCoTec 2021, the 12th International Federated Conference on Distributed Computing Techniques, but due to the COVID-19 pandemic it was held completely online.

We offered three distinct paper tracks: full research papers, full practical experience reports, and work-in-progress papers. We received 19 initial abstract submissions, 18 of which were for research papers and 1 for a practical experience report. All submissions were reviewed by three to four Program Committee (PC) members. The review process included a post-review discussion phase, during which the merits of all papers were discussed by the PC. The committee decided to accept six full research papers, two full practical experience reports, and two work-in-progress papers.

The accepted papers cover a broad range of topics in distributed algorithms, scalability and availability, network virtualization, stream processing, privacy, and trusted hardware.

The virtual conference, especially during these last months full of unpredictable events, was made possible by the hard work and cooperation of many people working in several different committees and organizations, all of which are listed in these proceedings. In particular, we are grateful to the PC members for their commitment and thorough reviews, and for their active participation in the discussion phase, and to all the external reviewers for their help in evaluating submissions. Finally, we also thank the DisCoTec general chair, Adrian Francalanza, and the DAIS Steering Committee chair, Luís Veiga, for their constant availability, support, and guidance.

June 2021

Miguel Matos
Fabiola Greve
# Organization

## General Chair

Adrian Francalanza University of Malta, Malta

## Program Committee Chairs

Miguel Matos University of Lisbon and INESC-ID, Portugal

Fabíola Greve Universidade Federal da Bahia, Brazil

## Steering Committee

Lydia Y. Chen TU Delft, Netherlands

Frank Eliassen University of Oslo, Norway

Rüdiger Kapitza Technical University of Braunschweig, Germany

Rui Oliveira University of Minho and INESC TEC, Portugal

Hans P. Reiser University of Passau, Germany

Laura Ricci University of Pisa, Italy

Silvia Bonomi Università degli Studi di Roma “La Sapienza”, Italy

Etienne Riviére Ecole Polytechnique de Louvain, Belgium

Jose Pereira University of Minho and INESC TEC, Portugal

Luís Veiga (Chair) INESC-ID and Universidade de Lisboa, Portugal

## Program Committee

Eduardo Alchieri Universidade de Brasília, Brazil

Pierre-Louis Aublin Keio University, Japan

Silvia Bonomi Università degli Studi di Roma “La Sapienza”, Italy

Davide Frey Inria, France

Paula Herber University of Münster, Germany

Mark Jelasity University of Szeged, Hungary

Vana Kalogeraki Athens University of Economics and Business, Greece

Evangelia Kalyvianaki University of Cambridge, UK

Fábio Kon University of São Paulo, Brazil

João Leitão Universidade Nova de Lisboa, Portugal

Kostas Magoutis University of Ioannina, Greece

Claudio Antares Mezzina University of Urbino, Italy

Hein Meling University of Stavanger, Norway

Alberto Montresor University of Trento, Italy

Daniel O’Keeffe Royal Holloway, University of London, UK

Emanuel Onica Alexandru Ioan Cuza University of Iasi, Romania

Marta Patino Universidad Politecnica de Madrid, Spain
<table><tr><td>José Orlando Pereira</td><td>Universidade do Minho and INESC TEC, Portugal</td></tr><tr><td>Hans P. Reiser</td><td>University of Passau, Germany</td></tr><tr><td>Romain Rouvoy</td><td>University of Lille, France</td></tr><tr><td>Valerio Schiavoni</td><td>University of Neuchâtel, Switzerland</td></tr><tr><td>Pierre Sutra</td><td>Telecom SudParis, France</td></tr><tr><td>Spyros Voulgaris</td><td>Athens University of Economics and Business, Greece</td></tr></table>

## Additional Reviewers

Christian Berger
Philipp Eichhammer
Johannes Köstler
Vitor Menino
# iExec: Building a Decentralized, Trusted and Privacy-Preserving Computing Infrastructure (Invited Speaker)

Gilles Fedak

CEO & co-founder of iExec, France

**Abstract.** iExec is a French startup company based in Lyon which built the first decentralized marketplace in which entities (e.g. traditional cloud providers, research centers and even individuals) can contribute and monetize Cloud Computing resources (CPU, GPU), Decentralized Applications (Dapps) and data-sets (Data Renting) in a secure and confidential way, ensuring the confidentiality and ownership of data. During this talk, I will present how iExec combines Ethereum Smart Contracts, a unique Proof-of-Contribution (PoCo) protocol and Trusted Execution Environments (TEE) to ensure trust between providers and consumers of resources. The project, however, is still facing several scientific and technological barriers related to scalability, interoperability and to supporting more classes of applications. I will discuss several research topics (e.g. ZK-proofs and rollups) and two H2020 projects in which iExec is involved: OntoChain, which aims at building a trusted and transparent knowledge management ecosystem and Datacloud, which goal is to build a platform for big data analytics in the edge-to-cloud continuum.
# Contents

## Cloud and Fog Computing

A Methodology for Tenant Migration in Legacy Shared-Table Multi-tenant Applications. Guillaume Rosinosky, Samir Youcef, François Charoy, and Etienne Rivière 3

Network Federation for Inter-cloud Operations Johannes Köstler, Sven Gebauer, and Hans P. Reiser 21

SPECK: Composition of Stream Processing Applications over Fog Environments. Davaadorj Battulga, Daniele Miorandi, and Cédric Tedeschi 38

## Fault Tolerance and Big Data

ASPAS: As Secure as Possible Available Systems Houssam Yactine, Ali Shoker, and Georges Younes 57

Portable Intermediate Representation for Efficient Big Data Analytics Giannis Tzouros, Michail Tsenos, and Vana Kalogeraki 74

## Distributed Algorithms

Shared-Dining: Broadcasting Secret Shares Using Dining-Cryptographers Groups David Mödinger, Juri Dispan, and Franz J. Hauck 83

UCBFed: Using Reinforcement Learning Method to Tackle the Federated Optimization Problem Wanqi Chen and Xin Zhou 99

## Trusted Environments

KEVLAR-TZ: A Secure Cache for ARM TRUSTZONE: (Practical Experience Report) Oscar Benedito, Ricard Delgado-Gonzalo, and Valerio Schiavoni 109

Analysis and Improvement of Heterogeneous Hardware Support in Docker Images Panagiotis Gkikopoulos, Valerio Schiavoni, and Josef Spillner 125
Invited Paper

<table><tr><td>Simulation of Large Scale Computational Ecosystems with Alchemist: A Tutorial</td><td>145</td></tr></table>

Danilo Pianini

<table><tr><td>Author Index</td><td>163</td></tr></table>