EN FR
EN FR


Section: New Results

Experimentation

This section covers our work on experimentation on testbeds (mainly Grid'5000), on emulation (mainly around the Distem emulator), and on Reproducible Research.

Grid'5000 design and evolutions

Participants : Florent Didier, Alexandre Merlin, Lucas Nussbaum [contact] , Olivier Demengeon [SED] , Teddy Valette [SED] .

The team was again heavily involved in the evolutions and the governance of the Grid'5000 testbed.

Technical team management Since the beginning of 2017, Lucas Nussbaum serves as the directeur technique (CTO) of Grid'5000 in charge of managing the global technical team (9 FTE).

SILECS project We are also heavily involved in the ongoing SILECS project, that aims to create a new infrastructure on top of the foundations of Grid'5000 and FIT in order to meet the experimental research needs of the distributed computing and networking communities. Since 2018, SILECS has been listed as part of the French National Roadmap for Very Large Research Infrastructures (TGIR program).

Grid'5000/FIT school We had a central role in the organization of the Grid'5000/FIT school that took place in Sophia-Antipolis in April 2018, gathering 93 participants. Lucas Nussbaum delivered a keynote talk presenting Grid'5000 and its recent evolutions [28]. A successful evaluation of Grid'5000 by its Scientific Advisory Board also took place during the school.

Storage manager A contribution from the team was the design and development of a new storage access manager that allows secure access to NFS home directories, thus closing a widely-spread security vulnerability.

I/O emulation support in Distem

Participants : Alexandre Merlin, Olivier Dautricourt, Abdulqawi Saif, Lucas Nussbaum [contact] .

Distem had a new release (version 1.3) at the beginning of 2018. This release mainly focused on bringing it up-to-date in terms of software quality (newer dependencies, added tests) and added some network emulation features that were previously missing.

The emulator was then featured in a tutorial during the Grid'5000/FIT school.

There is ongoing work on adding I/O emulation support in Distem, in order to experiment how Big Data solution can handle degraded situations. This is still pending completion and publication.

I/O access patterns analysis with eBPF

Participants : Abdulqawi Saif, Lucas Nussbaum [contact] , Ye-Qiong Song.

We explored the relevance of an emerging instrumentation technology for the Linux kernel, eBPF, and used it to analyze I/O access patterns such as non-sequential accesses, which are particularly harmful on non-SSD drives. We designed a tool to help with such analysis, and applied it to two popular NoSQL databases, MongoDB and Cassandra, outlining severe performance problems [19] with MongoDB, where a workload that should have resulted in sequential accesses was in fact turned into lots of random accesses.

Experiment Monitoring

Participants : Abdulqawi Saif, Alexandre Merlin, Lucas Nussbaum [contact] , Ye-Qiong Song.

Most computer experiments include a phase where metrics are gathered from and about various kinds of resources. This phase is often done via manual, non-reproducible and error-prone steps. We designed an experiment monitoring framework called MonEx, built on top of infrastructure monitoring solutions and supporting various monitoring approaches. MonEx fully integrates into the experiment workflow by encompassing all steps from data acquisition to producing publishable figures [18], [29].

Testbed federation and collaborations in the testbeds community

Participant : Lucas Nussbaum [contact] .

The Fed4FIRE+ H2020 project started in January 2017 and will run until the end of September 2021. This project aims at consolidating the federation of testbeds in Europe of which Grid'5000 is a member. In 2018, we focused on various aspects related to experiment reproducibility.

We are also active in the GEFI initiative that aims at building links between the US testbeds community (GENI) and their European (FIRE), Japanese and Brazilian counterparts. We participated in the annual GEFI meeting where we chaired two sessions on Experiment reproducibility and Networking experiments, respectively, and gave one talk on Experiment data management, outlining the recent work that was done on Grid'5000 on disk reservation [27].

Blockchain experimentation

Participants : Jérôme François [Contact] , Wazen Shbair [University of Luxembourg, Luxembourg] , Radu State [University of Luxembourg, Luxembourg] , Mathis Steichen [University of Luxembourg, Luxembourg] .

The experimentation of distributed applications like blockchains needs a highly reconfigurable and controllable environment for fine-tuning blockchain and network parameters in different scenarios. Therefore, there might be significant manual operations which lead to human errors and make it hard to reproduce experiments. We proposed an easy to use orchestration framework over the Grid'5000 platform [23]. Our tool can fine-tune blockchain and network parameters before and between experiments. The proposed framework offers insights for private and consortium blockchain developers to identify performance bottlenecks and to assess the behavior of their applications in different circumstances.

NDN experimentation

Participants : Thibault Cholez [Contact] , Xavier Marchal, Olivier Festor.

While ICN is a promising technology, we currently lack experiments carrying real user traffic. This also highlights the difficulty of making the link between the new NDN world and the current IP world. To address this issue, we designed and implemented an HTTP/NDN gateway (composed of ingress and egress gateways) that can transport the traffic of regular web users over an NDN island. Users just need to configure the ingress gateway as a standard web proxy that will be the entry point to the virtualized NDN island, and their traffic is seamlessly transported over NDN, thus benefiting from the good properties of the protocol to deliver content (request mutualization, caching, etc.). HTTP requests/responses are converted into NDN Interest/Data and the answer can either come from the island, or from the web through the egress gateway. Our first functional experimental results of an initial testbed deployment exhibit the capability of our global infrastructure to retrieve the top-1000 most popular web sites without difficulty [17]. This opens the way to wider and more realistic experiments of NDN with real traffic. In particular, the gateway was used to perform QoE experiments involving real users from Nancy and Troyes. They accessed many websites through the NDN network in a very satisfying way.