Management of distributed systems emphasizing on business process enactment in real-time clouds

The aim of this thesis is the study of distributed Grid and Cloud environments and particularly the mechanisms needed to manage and execute business workflows in virtualized environments. Particular attention is given to the QoS guarantees that these systems need to provide in order for soft real-time applications to be deployed, managed and executed. For this reason, the requirements that interactive applications have are analyzed, existing workflow management systems are studied and the real-time offerings of modern operating systems are researched. Following, we present an architectural solution that can provide the necessary services and tools that enable modeling and execution of interactive applications in distributed Cloud environments. The proposed solution is verified and evaluated through a series of experiments as well as through real-life applications and its advantages are presented. Finally, a scalable monitoring solution able to perform aggregation is presented and evaluated.Σκοπός της παρούσης διατριβής είναι η μελέτη των κατανεμημένων περιβαλλόντων Πλέγματος (Grid) και Νέφους (Cloud) και ιδιαιτέρως οι μηχανισμοί ελέγχου και εκτέλεσης ροών εργασίας (workflows) σε εικονικοποιημένα (virtualized) περιβάλλοντα. Ιδιαίτερη σημασία δίνεται στην ανάγκη παροχής εκ μέρους των συστημάτων αυτών εγγυήσεων Ποιότητας Υπηρεσίας ώστε να μπορούν να εκτελεστούν εφαρμογές ελαστικού πραγματικού χρόνου (soft real-time). Για τον λόγο αυτό, αναλύονται οι απαιτήσεις που έχουν οι διαδραστικές εφαρμογές, τα υπάρχοντα συστήματα διαχείρισης ροών εργασίας καθώς και οι δυνατότητες που παρέχουν τα σύγχρονα λειτουργικά συστήματα για εκτέλεση εφαρμογών πραγματικού χρόνου. Στη συνέχεια παρουσιάζεται μία αρχιτεκτονική λύση η οποία μπορεί να παρέχει τις απαιτούμενες υπηρεσίες και μηχανισμούς που επιτρέπουν την μοντελοποίηση και εκτέλεση διαδραστικών εφαρμογών σε κατανεμημένα περιβάλλοντα Νέφους. Η προτεινόμενη λύση επαληθεύεται και αξιολογείται μέσω σειράς πειραμάτων καθώς και μέσω πραγματικών εφαρμογών και παρουσιάζονται τα πλεονεκτήματα. Τέλος, παρουσιάζεται μία λύση για την επίβλεψη κατανεμημένων συστημάτων που εμφανίζει σημαντικές δυνατότητες κλιμάκωσης και συνάθροισης των παρατηρούμενων μετρικών

Management of Distributed Systems Emphasizing on Business Process Enactment in Real-time Clouds

208 σ.Σκοπός της παρούσης διατριβής είναι η μελέτη των κατανεμημένων περιβαλλόντων Πλέγματος (Grid) και Νέφους (Cloud) και ιδιαιτέρως οι μηχανισμοί ελέγχου και εκτέλεσης ροών εργασίας (workflows) σε εικονικοποιημένα (virtualized) περιβάλλοντα. Ιδιαίτερη σημασία δίνεται στην ανάγκη παροχής εκ μέρους των συστημάτων αυτών εγγυήσεων Ποιότητας Υπηρεσίας ώστε να μπορούν να εκτελεστούν εφαρμογές ελαστικού πραγματικού χρόνου (soft real-time). Για τον λόγο αυτό, αναλύονται οι απαιτήσεις που έχουν οι διαδραστικές εφαρμογές, τα υπάρχοντα συστήματα διαχείρισης ροών εργασίας καθώς και οι δυνατότητες που παρέχουν τα σύγχρονα λειτουργικά συστήματα για εκτέλεση εφαρμογών πραγματικού χρόνου. Στη συνέχεια παρουσιάζεται μία αρχιτεκτονική λύση η οποία μπορεί να παρέχει τις απαιτούμενες υπηρεσίες και μηχανισμούς που επιτρέπουν την μοντελοποίηση και εκτέλεση διαδραστικών εφαρμογών σε κατανεμημένα περιβάλλοντα Νέφους. Η προτεινόμενη λύση επαληθεύεται και αξιολογείται μέσω σειράς πειραμάτων καθώς και μέσω πραγματικών εφαρμογών και παρουσιάζονται τα πλεονεκτήματα. Τέλος, παρουσιάζεται μία λύση για την επίβλεψη κατανεμημένων συστημάτων που εμφανίζει σημαντικές δυνατότητες κλιμάκωσης και συνάθροισης των παρατηρούμενων μετρικών.The aim of this thesis is the study of distributed Grid and Cloud environments and particularly the mechanisms needed to manage and execute business workflows in virtualized environments. Particular attention is given to the QoS guarantees that these systems need to provide in order for soft real-time applications to be deployed, managed and executed. For this reason, the requirements that interactive applications have are analyzed, existing workflow management systems are studied and the real-time offerings of modern operating systems are researched. Following, we present an architectural solution that can provide the necessary services and tools that enable modeling and execution of interactive applications in distributed Cloud environments. The proposed solution is verified and evaluated through a series of experiments as well as through real-life applications and its advantages are presented. Finally, a scalable monitoring solution able to perform aggregation is presented and evaluated.Σπυρίδων Β. Γωγουβίτη

SLAs in Virtualized Cloud Computing Infrastructures with QoS Assurance

Cloud Computing is gaining momentum as one of the technologies that promises to subvert our own idea of computing. With an increasing usage of cloud applications and their consequent dependency from connectivity, the nowadays Personal Computer is becoming merely a mobile device acting as a front-end to on-line applications and services. This huge paradigm shift in computing is witnessed for example by big market players who announced the imminent launch of innovative products and Operating Systems (like Chrome notebooks and the accompanying Chrome OS2. by Google), which are capable of projecting the user into the network in a few seconds by booting and starting immediately a web browser and (mostly) nothing else. In such a challenging scenario, more and more of the applications that we traditionally used locally on our PC are being hosted on cloud infrastructures and operated remotely through the Internet. This includes not only batch tasks, but also interactive applications which need to operate inherently with good levels of responsiveness. In this paper, the challenging problem is discussed of how to ensure predictable levels of Quality of Service (QoS) to cloud applications across the multiple layers of a typical cloud infrastructure, and how a reasonable Service Level Agreement (SLA) management and enforcement policy might look like. The scope of this paper represents a hands-on experience that was gained by the authors realising the IRMOS real-time cloud-computing infrastructure in the context of the IRMOS European Project

A Comparison of Two Different Approaches to Cloud Monitoring

Monitoring is a relevant issues above all for customers of Public Clouds. In fact they need to detect under-utilization, overload conditions, and check SLA fulfillment. However they cannot trust twice the provider for the SLA and for its checking, and have limited knowledge about the infrastructure to understand the reasons of real bottlenecks. They can only access the virtual resources. In this Chapter we provide a comparison of two different approaches to the monitoring of Clouds Infrastructure, developed within the research activities of two European FP7-ICT projects. The first one has been developed by the VISION Cloud project and it is based on asynchronous message delivery mechanism for the collection, propagation and delivery of all events to their respective recipients. The second one is based on , the mobile agents framework of the mOSAIC project, for provisioning and managements of heterogeneous Cloud resources

D5.1.1 Models of Real-time Applications on Service Oriented Infrastructures

The IRMOS project is developing tools and techniques for modelling, simulating, analysing, and planning real-time applications on service oriented infrastructures. These tools and techniques support the processes involved in designing, developing, deploying and executing applications where guaranteed QoS is needed. The report considers the value-chain for real-time applications hosted by third-party service providers. In the context of this value chain, we analyse who might benefit from the use of models, how and why these models might be used, and when during the application lifecycle modelling is most useful. Techniques are presented for building models of real-time applications including the use of stochastic process algebras, finite state automata, workflow models (e.g. BPEL, BPMN and YAWL) and specification languages (e.g. UML MARTE). The report discusses how these models need to be supported by estimation of application resource consumption, e.g. through benchmarking and fitting, and how mapping techniques allow models to be built for different actors in the value chain, e.g. for application providers and infrastructure providers. Tool support is also discussed e.g. PRISM for probabilistic model checking and Visual Service Composition Studio for service-oriented modelling. A detailed and specific real-time application scenario is included and modelled to allow the various techniques presented in this document to be demonstrated and quantitatively evaluated. The scenario also reveals the level of detail needed in order for meaningful modelling to be achieved in practice. The modelling scenario has been carefully engineered to be as representative as possible of the broad range of application characteristics encountered in the three reference IRMOS applications (film postproduction, eLearning, virtual and augmented reality). The modelling techniques discussed and then demonstrated in this report include identifying what resources are necessary to support an application, when those resources will be required during the application workflow, what performance is needed from them (i.e. QoS) and what will happen to the application if the required performance is not delivered. All of these are essential when developing and then agreeing service level agreements between the various entities in a service oriented infrastructure

A Service Oriented Architecture for achieving QoSaware Workflow Management in Virtualized Environments

Abstract—The advancements in distributed computing have driven the emergence of service-based infrastructures that allow for on-demand provision of ICT assets. Taking into consideration the complexity of distributed environments, significant challenges exist in providing and managing the offered on-demand resources with the required level of Quality of Service (QoS), especially for real-time interactive multimedia applications. Common to these applications is the service-oriented approach being followed, thus applications consist of application service components that interact in order to provide the corresponding application functionality. In this paper we present an architectural design of a complete Workflow Management System (WfMS) for enacting application service components that have been deployed in a Virtualized Environment. The WfMS aims at synchronizing the application components, monitoring their execution and handling faults while adhering to the QoS requirements of the application