Tromino: Demand and DRF Aware Multi-Tenant Queue Manager for Apache Mesos Cluster

Apache Mesos, a two-level resource scheduler, provides resource sharing across multiple users in a multi-tenant cluster environment. Computational resources (i.e., CPU, memory, disk, etc. ) are distributed according to the Dominant Resource Fairness (DRF) policy. Mesos frameworks (users) receive resources based on their current usage and are responsible for scheduling their tasks within the allocation. We have observed that multiple frameworks can cause fairness imbalance in a multiuser environment. For example, a greedy framework consuming more than its fair share of resources can deny resource fairness to others. The user with the least Dominant Share is considered first by the DRF module to get its resource allocation. However, the default DRF implementation, in Apache Mesos' Master allocation module, does not consider the overall resource demands of the tasks in the queue for each user/framework. This lack of awareness can result in users without any pending task receiving more resource offers while users with a queue of pending tasks starve due to their high dominant shares. We have developed a policy-driven queue manager, Tromino, for an Apache Mesos cluster where tasks for individual frameworks can be scheduled based on each framework's overall resource demands and current resource consumption. Dominant Share and demand awareness of Tromino and scheduling based on these attributes can reduce (1) the impact of unfairness due to a framework specific configuration, and (2) unfair waiting time due to higher resource demand in a pending task queue. In the best case, Tromino can significantly reduce the average waiting time of a framework by using the proposed Demand-DRF aware policy

Transparent Orchestration of Task-based Parallel Applications in Containers Platforms

This paper presents a framework to easily build and execute parallel applications in container-based distributed computing platforms in a user-transparent way. The proposed framework is a combination of the COMP Superscalar (COMPSs) programming model and runtime, which provides a straightforward way to develop task-based parallel applications from sequential codes, and containers management platforms that ease the deployment of applications in computing environments (as Docker, Mesos or Singularity). This framework provides scientists and developers with an easy way to implement parallel distributed applications and deploy them in a one-click fashion. We have built a prototype which integrates COMPSs with different containers engines in different scenarios: i) a Docker cluster, ii) a Mesos cluster, and iii) Singularity in an HPC cluster. We have evaluated the overhead in the building phase, deployment and execution of two benchmark applications compared to a Cloud testbed based on KVM and OpenStack and to the usage of bare metal nodes. We have observed an important gain in comparison to cloud environments during the building and deployment phases. This enables better adaptation of resources with respect to the computational load. In contrast, we detected an extra overhead during the execution, which is mainly due to the multi-host Docker networking.This work is partly supported by the Spanish Government through Programa Severo Ochoa (SEV-2015-0493), by the Spanish Ministry of Science and Technology through TIN2015-65316 project, by the Generalitat de Catalunya under contracts 2014-SGR-1051 and 2014-SGR-1272, and by the European Union through the Horizon 2020 research and innovation program under grant 690116 (EUBra-BIGSEA Project). Results presented in this paper were obtained using the Chameleon testbed supported by the National Science Foundation.Peer ReviewedPostprint (author's final draft

Flux qubit on mesoscopic nonsuperconducting ring

The possibility of making a flux qubit on nonsuperconducting mesoscopic ballistic quasi 1D ring is discussed. We showed that such ring can be effectively reduced to a two-state system with two external control parameters. The two states carry opposite persistent currents and are coupled by tunneling which leads to a quantum superposition of states. The qubit states can be manipulated by resonant microwave pulses. The flux state of the sample can be measured by a SQUID magnetometer. Two or more qubits can be coupled by the flux the circulating currents generate. The problem of decoherence is also discussed.Comment: Phys. Rev. B. (accepted

Vasopressina, un nou biomarcador en insuficiència cardíaca

Introducció. Les concentracions plasmàtiques dels pèptids natriürètics són biomarcadors útils en el diagnòstic i en el maneig de la insuficiència cardíaca (IC). L'objectiu de l'estudi va consistir en avaluar un nou biomarcador, la vasopressina, per predir la mortalitat i el reingrés a mig termini dels pacients que ingressen per IC aguda. Mètodes. Des del novembre de 2004 fins setembre de 2010 s'estudien de forma prospectiva el pacients que ingressen al Servei de Cardiologia per IC aguda i es distribueixen en dos grups: grup 1, pacients amb nivells baixos de vasopressina ( ≤ 2'9 pg/mL) i grup 2, pacients amb nivells alts de vasopressina ( 2'9 pg/mL). Es realitza una anàlisi multivariada de Cox i es construeixen corbes de Kaplan-Meier. Resultats. S'inclouen 322 pacients, amb una mediana de seguiment de 14,6 mesos. Els pacients del grup 1 presenten una major supervivència als 12 i 24 mesos del 93% i 72% respecte els pacients del grup 2 que és del 75% i 61% amb una HR 2.90 (IC 95%: 1.47-5.75, p=0.002), respectivament. Tanmateix s'aprecia una major supervivència cardiovascular en els pacients del grup 1 (97% vs. 87% al 12 mesos i de 87% vs. 75% als 24 mesos) amb HR 2.72 (IC 95%: 1.97 - 6.73, p 0.031). Un 56% i 29% dels pacients del grup 1 estaven lliures de reingrés als 12 i 24 mesos, respectivament, versus el 49% i el 21% del grup 2 amb una HR 1.48 (IC 95%: 1.04 - 2.11, p 0.02). Igualment pel primer reingrés per IC , el 71% i 46% del grup 1 respecte del 60% i 39% del grup 2 als 12 i 24 mesos, respectivament (HR 1.57 (IC 95%: 1.03 - 2.41, p 0.038). Conclusions. Els nivells alts de vasopressina en pacients amb insuficiència cardíaca aguda estabilitzats són un predictor independent de mortalitat i de reingressos als 12 i 24 mesos de seguiment