Collision avoidance for Delay_Req messages in broadcast media

The time accuracy of the Precision Time Protocol deteriorates in consequence to Delay req/Delay resp session collisions common for applications using shared broadcast media. In this paper we propose a protocol that coordinates Delay_req/Delay_resp sessions with minimum changes to the original PTP protocol. Simulations illustrate protocol’s operation and demonstrate significant reduction of session collisions

Beyond Nagios - Design of a cloud monitoring system

The paper describes a monitoring system specially designed for cloud infrastructures. The features that are relevant for such distributed application are -) scalability, that allows utilization in systems of thousands of nodes, -) flexibility, to be customized for a large number of applications, -) openness, to allow the coexistence of user and administration monitoring. We take as a starting point the Nagios monitoring system, that has been successfully used for Grid monitoring and is still used for clouds. We analyze its shortcomings when applied to cloud monitoring, and propose a new monitoring system, that we call Rocmon, that sums up Nagios experience with a cloud perspective. Like Nagios, Rocmon is plugin-oriented to be flexible. To be fully inter-operable and long-living, it uses standard tools: the OGF OCCI for the configuration interface, the REST paradigm to take advantage of Web tools, and HTML5 WebSockets for data transfers. The design is checked with an open source Ruby implementation featuring the most relevant aspects

Automated Deployment of a Microservice-based Monitoring Infrastructure

We explore the specification and the automated deployment of a monitoring infrastructure in a container-based distributed system. This result shows that highly customizable monitoring infrastructures can be effectively provided as a service, and that a key step in this process is the definition of an expandable abstract model for them. So we start defining a simple model of the monitoring infrastructure that provides an interface between the user and the cloud management system. The interface follows the guidelines of Open Cloud Computing Interface (OCCI), the cloud interface standard proposed by the Open Grid Forum. The definition is simple and generic and it is a first step towards the definition of a standard interface for Monitoring Services. It allows the definition of complex, hierarchical monitoring infrastructure by composing multiple instances of two basic components, one for measurement and another for data distribution,. We illustrate how the monitoring functionalities that are defined through the interface are implemented as microservices embedded in containers. The internals of each microservice reflects the distinction between core functionalities which are bound to the standard, and custom plugin modules. We describe the engine that automatically deploys a system of microservices that implements the monitoring infrastructure. Special attention is paid to preserve the distinction between core and custom functionalities, and the on demand nature of a cloud service. A proof of concept demo is available through the Docker hub and consists of two multi-threaded Java appli- cations that implement the two basic components

Teaching networks in the cloud

The Web is populated by a growing number of services that provide access to remote IT resources: they are col- lectively addressed as the Cloud. Such incoherent and expanding number of services is investigated to find those that can help the task of teaching, focusing on a challenging case study for which I have a direct experience: a course in computer networks with the purpose of giving the students a hands-on experience using production-grade techniques. The outcome of the case study is that on-line services can complement traditional frontal lectures, to enrich the communi- cation between the teacher and the student, and to improve the learning experience. This is a hint for teachers, and characterizes a potential market for developers and providers

Application level interface for a cloud monitoring service

We introduce a new paradigm, based on an extension of the Open Cloud Computing Interface (OCCI), for the on demand monitoring of the cloud resources provided to a user. We have extended the OCCI with two new sub-types of core entities: one to collect the measurements, and the other to process them. The user can request instances of such entities to implement a monitoring infrastructure. The paradigm does not target a specific cloud model, and is therefore applicable to any kind of resource provided as a service. The specifications include only the minimum needed to describe a monitoring infrastructure, thus making this standard extension simple and easily adoptable. Despite its simplicity the model is able to describe complex solutions, including private/public clouds, and covers both infrastructure and application monitoring. To highlight the impact of our proposal in practice, we have designed an engine that deploys a monitoring infrastructure using its OCCI-compliant descriptions. The design is implemented in a prototype that is available as open source