Device drivers constitute a significant portion of an operating system's source code. The effort to develop a new driver set is a sobering hurdle to the pursuit of novel operating system ventures. A practical solution is to reuse drivers, but this can contradict design goals in a new operating system. We offer a new approach to device-driver reuse, with a focus on promoting novel operating-system construction, which insulates the new operating system from the invariants of the reused drivers, while also addressing development effort. Our solution runs the drivers along with their original operating systems inside virtual machines, with some minor reuse infrastructure added to the driver's operating system to interface with the rest of the system. This approach turns the drivers into de-privileged applications of the new operating system, which separates their architectures and reduces cross-influences, and improves system dependability. Virtual machines help reuse drivers, but they also penalize performance. The known solution for improving virtual machine performance, para-virtualization, modifies the operating system to run on a hypervisor, which has an enormous cost: substantial development effort, and abandonment of many of virtualization's benefits such as modularity. These costs contradict our goals for driver reuse: to reduce development effort, and to easily reuse from a variety of operating systems. Thus we introduce a new approach to constructing virtual machines: pre-virtualization. Our solution combines the performance of para-virtualization with the modularity of traditional virtual machines. We still modify the operating system, but according to a set of principles called soft layering that preserves modularity, and via automation which reduces implementation costs. With pre-virtualization we can easily reuse device drivers. We describe our driver-reuse approach applied to a real system: we run virtual machines on the L4Ka::Pistachio microkernel, with reused Linux drivers. We include an evaluation and demonstrate that we achieve throughput comparable to the native Linux drivers, but with moderately higher CPU and memory utilization. Additionally, we describe how to apply pre-virtualization to multiple hypervisor environments. We include an evaluation of pre-virtualization, and demonstrate that it achieves comparable performance to para-virtualization for both the L4Ka::Pistachio and Xen hypervisors, with modularity.

Software systems may contain sensitive data that should be protected. In a scenario, where an analyst has full access to the system, it may be desirable to transform the program to become harder to understand and reverse-engineer, while preserving the original functionality of the program. Machine code obfuscation tackles this problem by adding complexity to the pro- gram's control flow, a programming idiom removal, and various abstractions. Specifically, WProtect is an obfuscation engine that utilises a stack virtual ma- chine and its own instruction set to achieve these properties. In this thesis, I will analyse WProtect obfuscation engine, its obfuscation algo- rithms and present a generic approach to an extraction of a code protected by WProtect. Furthermore, I will design a generic framework for a static code ex- traction that is tweakable in order to support different WProtect configurations. Several improvements to WProtect, both in terms of configuration and design, will also be proposed. These proposals mostly intend to mitigate vulnerabilities that are exploited in the code extraction, however, several proposals shall also include improvements specifically targeting static analysis prevention. 1

Currently systems of virtual machines are load balanced statically which can create load imbalances for systems where the load changes dynamically over time. For throughput and response time of a system to be maximized it is necessary for load to be evenly distributed among each part of the system. We implement a prototype policy engine for the Xen virtual machine monitor which can dynamically load balance virtual machines. We compare the throughput and response time of our system using the cpu2000 and the WEB2005 benchmarks from SPEC. Under the loads we tested, dynamic load balancing had 5%-8% higher throughput than static load balancing.

Since a massive decline of computer science graduates in 2002, computer science departments have been unable to reach previous graduation rates. In wake of this dramatic loss of graduates, researchers have been searching for the reasons students are avoiding computer science and choosing other majors. To combat this decrease in computer science graduates, the CloudSpace environment pro- vides additional context to entry level computer science courses. This shift in context re- moves boring assignments from the early computer science curriculum and replaces them with more engaging web centric assignments. The CloudSpace environment presents a model that maintains student's focus on core computer science competencies while providing a highly simplified web development toolkit to develop feature rich AJAX web applications. This the- sis includes the rational and implementation of a cloud based hosting service and a highly abstracted web tool kit that enables students to replicate modern web applications. / Master of Science

In an era with compelling need for greater computation power, the aggregation of software system components is becoming more challenging and diverse. The new-generation scientific applications are growing hub of complex and intense computation performed on huge data set with exponential growth. With the development of parallel algorithms, design of multi-user web applications and frequent changes in software architecture, there is a bigger challenge lying in front of the research institutes and organizations. Network science is an interesting field posing extreme computation demands to sustain complex large-scale networks. Several static or dynamic network analysis have to be performed through algorithms implementing complex graph theories, statistical mechanics, data mining and visualization. Similarly, high performance computation infrastructures are imbibing multiple characters and expanding in an unprecedented way. In this age, it's mandatory for all software solutions to migrate to scalable platforms and integrate cloud enabled data center clusters for higher computation needs. So, with aggressive adoption of cloud infrastructures and resource-intensive web-applications, there is a pressing need for a dynamic middleware to bridge the gap and effectively coordinate the integrated system. Such a heterogeneous environment encourages the devising of a transparent, portable and flexible solution stack. In this project, we propose adoption of Virtual Machine aware Portable Batch System Cluster (VM-aware PBS Cluster), a self-initiating and self-regulating cluster of Virtual Machines (VM) capable of operating and scaling on any cloud infrastructure. This is an unique but simple solution for large-scale softwares to migrate to cloud infrastructures retaining the most of the application stack intact. In this project, we have also designed and implemented Cloud Integrator Framework, a dynamic implementation of cloud aware middleware for the proposed VM-aware PBS cluster. This framework regulates job distribution in an aggregate of VMs and optimizes resource consumption through on-demand VM initialization and termination. The model was integrated into CINET system, a network science application. This model has enabled CINET to mediate large-scale network analysis and simulation tasks across varied cloud platforms such as OpenStack and Amazon EC2 for its computation requirements. / Master of Science

Context. Light weight process virtualization has been used in the past e.g., Solaris zones, jails in Free BSD and Linux’s containers (LXC). But only since 2013 is there a kernel support for user namespace and process grouping control that make the use of lightweight virtualization interesting to create virtual environments comparable to virtual machines. Telecom providers have to handle the massive growth of information due to the growing number of customers and devices. Traditional databases are not designed to handle such massive data ballooning. NoSQL databases were developed for this purpose. Cassandra, with its high read and write throughputs, is a popular NoSQL database to handle this kind of data. Running the database using operating system virtualization or containerization would offer a significant performance gain when compared to that of virtual machines and also gives the benefits of migration, fast boot up and shut down times, lower latency and less use of physical resources of the servers. Objectives. This thesis aims to investigate the trade-off in performance while loading a Cassandra cluster in bare-metal and containerized environments. A detailed study of the effect of loading the cluster in each individual node in terms of Latency, CPU and Disk throughput will be analyzed. Methods. We implement the physical model of the Cassandra cluster based on realistic and commonly used scenarios or database analysis for our experiment. We generate different load cases on the cluster for bare-metal and Cassandra in docker scenarios and see the values of CPU utilization, Disk throughput and latency using standard tools like sar and iostat. Statistical analysis (Mean value analysis, higher moment analysis, and confidence intervals) are done on measurements on specific interfaces in order to increase the reliability of the results. Results.Experimental results show a quantitative analysis of measurements consisting Latency, CPU and Disk throughput while running a Cassandra cluster in Bare Metal and Container Environments.A statistical analysis summarizing the performance of Cassandra cluster is surveyed. Results.Experimental results show a quantitative analysis of measurements consisting Latency, CPU and Disk throughput while running a Cassandra cluster in Bare Metal and Container Environments.A statistical analysis summarizing the performance of Cassandra cluster is surveyed. Conclusions. With the detailed analysis, the resource utilization of the database was similar in both the bare-metal and container scenarios. Disk throughput is similar in the case of mixed load and containers have a slight overhead in the case of write loads for both the maximum load case and 66% of maximum load case. The latency values inside the container are slightly higher for all the cases. The mean value analysis and higher moment analysis helps us in doing a finer analysis of the results. The confidence intervals calculated show that there is a lot of variation in the disk performance which might be due to compactions happening randomly. Future work in the area can be done on compaction strategies.

[pt] O objetivo deste trabalho é estudar, propor e implementar uma ferramenta que permita a experimentação com arquiteturas que sigam o paradigma de Processadores de Rede - Network Processors (NP). Com esse intuito, foi implementada uma biblioteca de objetos genéricos que permite emular os diversos componentes de hardware (tais como memórias, registradores, unidades de controle, unidades lógico-aritméticas, etc.) presentes em arquiteturas especificas para o processamento de protocolos. A conjunção desses componentes permite gerar máquinas virtuais que podem ser exercitadas para testar ou verificar o funcionamento das mais diversas operações nesses ambientes. Além da biblioteca, são apresentados três estudos de casos distintos: o primeiro mostrando um processador criado para teste e os outros dois implementam arquiteturas baseadas no processador MCS85 e no núcleo ARM do Processador IXP, todos com o intuito de validar e mostrar a utilidade prática da ferramenta. / [en] The aim of this work is to study, propose and implement a tool that allows the experimentation with architectures that follow the Network Processors (NP) paradigm. A generic object library was implemented, allowing the emulation of the various hardware components, such as memories, registers, arithmetic-and-logical units, control units etc., that are commonly used within specific architectures for protocol processing. The integrated usage of these components will provide an environment where virtual machines can be created and tested to verify the behavior of many different operations. Besides the library itself, three use cases are presented to validate and show the utility of the tool: the first is an implementation of a processor created just for the sake of testing and the other two are implementations of architectures based on the MCS85 processor and on the ARM kernel of the Intel IXP Network Processor.

Variations between the software environments(e.g., installed applications, versions of libraries) on different high-performance computing (HPC) systems lead to a heterogeneity problem. Therefore, we design an optimized, homogeneous virtual machine (VM) called a virtual application appliance (VAA). Scientists can package scientific applications, and all supporting software components, as VAAs and run them independently from the underlying heterogeneous HPC systems. However, securely moving data in and out of the VAA and controlling the execution of applications are not trivial for a non-computer scientist. Consequently, we develop two automated stage-in/stage-out secure data movement mechanisms. We also explore a migration mechanism to further simplify the control of the VAA execution. Empirical evaluation results show that VAAs achieve near-native performance in widely used bioinformatics applications that we tested. Data movement, VM boot up, shutdown and migration overheads of VAAs are negligible with respect to total run-times.

Ο σκοπός της παρούσας εργασίας είναι η ανάπτυξη ενός daemon που θα ελέγχει ένα σύνολο από virtual machines, και θα τα χρησιμοποιεί προκειμένου να εξομοιώνονται λειτουργίες δικτύων υπολογιστών. Κάθε ενεργό στιγμιότυπο ενός virtual machine θα έχει ασφαλώς το ρόλο ενός (εικονικού) υπολογιστή. Οι λειτουργίες που υλοποιεί ο κώδικας είναι η δημιουργία, ο έλεγχος και η μεταβολή ενός δικτύου εικονικών υπολογιστών, μέσω ενός μενού επιλογών, το οποίο ταυτόχρονα παρέχει πληροφορίες για κάθε εικονικό υπολογιστή. Η υλοποίηση του δικτύου γίνεται με τη χρήση του User Mode Linux (ενός Linux virtual machine)ενώ κάθε ενεργό UML στιγμιότυπο (UML instance) του virtual machine έχει το ρόλο ενός εικονικού υπολογιστή. Η ευελιξία που παρέχεται από τα Virtual Machines είναι τεράστια, και τα καθιστά ιδανικά για το δίκτυο που θα κάνουμε. Η συμπεριφορά του εξάλλου θα είναι όμοια με αυτή ενός πραγματικού δικτύου. / Creation of a daemon process, used to control a large number of Linux Virtual Machines and create a Virtual Machine network out of them.

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