V informatice je pojem entropie obvykle znám jako nahodný proud dat.  Tato práce krátce shrnuje metody generovaní nahodných dat a popisuje generátor náhodnych čísel, jež je obsažen v jádře operačního systému Linux.  Dále se práce zabývá určením bitové rychlosti generování nahodných dat tímto generátorem ve virtualizovaném prosředí, které poskytují různé hypervizory.  Práce popíše problémy nízkého výkonu generátory nahodných dat ve virtualním prostředí a navrhne postup pro jejich řešení.  Poté je nastíňena implementace navržených postupů, které je podrobena testům a její vysledky jsou porovnány s původním systémem. Systém pro distribuci entropie může dále vylepšit množství entropie v sytémovém jádře o několik řádu, pokud je připojen k vykonému generátoru nahodných dat.

The purpose of master's thesis is preparing the proposal for optimization of servers using virtualization and consolidation. The master's thesis is divided into three parts. The first one is engaged theoretical ground of computer network, second part analyses the current state of IT infrastructure within the specific business. The last part contains the proposal to modernization and optimization of existing server solution including summary of expected costs for realization od proposal.

The diploma thesis ’Virtualization of Operating Systems’ deals with a general description of virtualization technology and briefly discusses its use cases and advantages. The thesis also mentions examples of different types of virtualization technologies and tools, including more thorough description of the two technologies used for measurement: Docker and KVM. The second part of this thesis descibes the preparation, installation and configuration of all the tools and services that are necessary for measurement of the influence of the aforementioned virtualization technologies on network services running on the virtual machines, including analysis and discussion of the resulting data. Moreover, a custom application for fully automated measurement of the parameters of network services was created, and is also described in this thesis. The conclusion of this thesis summarizes and discusses the achieved results and acknowledges the influence of virtualization on network services, where the Docker application containers, which are with their low overhead comparable to a "bare" system without any virtualization, managed to achieve much better performance results than the traditional virtual machines on KVM.

Tato práce se zabývá problematikou virtualizace, konkrétně virtualizační knihovnou libvirt, cílem které je správa virtuálních strojů a podpora různých typů hypervizorů a virtualizačních řešení jednotným způsobem transparentním pro uživatele. Podstatná část funkcionality knihovny libvirt je na pozadí implementována formou démona libvirtd. Ačkoliv libvirtd démon poskytuje služby pro správu virtuálních strojů, neumožňuje správu sebe samého, kromě změn hodnot parametrů v konfiguračním souboru. Pro změnu nastavení je pak standardním přístupem změna v konfiguračním souboru a následný restart démona. Jelikož uvedený způsob mění pouze perzistentní konfiguraci a restart démona nemusí být vždy optimální řešení, vznikla idea administrativního rozhraní knihovny libvirt, které by umožnilo správu démona za běhu. Hlavním přínosem této práce je návrh a popis implementace aplikačního rozhraní pro administraci knihovny libvirt. Konkrétně pro tuto práci byla zvolena rozhraní pro konfiguraci počtu obslužných vláken, nastavení úrovně a filtrovacích parametrů pro žurnálovací podsystém a správu připojených klientů na straně démona libvirtd.

This thesis discusses software containers (Docker containers in particular) as a variant of server virtualization. Instead of virtualizing hardware, software containers rest on top of a single operating system instance and are much more efficient than hypervisors in system resource terms. Docker containers make it easy to package and ship applications, and guarantee that applications will always run the same, regardless of the environment they are running in. There is a whole range of use cases of containers, this work examines their usage in the field of software testing. The thesis proposes three main use case categories for running software systems in Docker containers. It introduces aspects for applications running in containers, which should give a better overview about an application setting within containers infrastructure. Subsequently, possible issues with testing software systems running inside Docker containers are discussed and the testing methods which address the presented issues are proposed. One proposed testing method was also used in the implementation of the framework for testing software running in Docker containers which was developed within this work.

Systems for automated evaluation of assignments are a valuable aid for both teachers of programming courses and their students. The objective of this thesis is to examine the possibilities of deploying such systems in a large-scale distributed environment and the challenges of such endeavors. A sizable part of the requirements comes from experience with ReCodEx - an assignment evaluation system developed at the department of the supervisor. Modern server multi-core processors provide considerable computing power that can be used for assignment evaluation. However, parallel measurements can interfere with each other. This causes unstable results, which detriments the fairness of grading. Isolation (sandboxing) technologies can cause similar effects. We measure both of these influences and use the results to determine to what degree can multi-core processors be exploited. The problem of efficient distribution of work between multiple evaluation workers is complementary to that of utilizing multi-core machines. We survey scheduling algorithms and design an experiment to compare their performance. Additionally, we examine the possibility of leveraging container technologies to simplify the deployment of software required for evaluation. This leads to both a smaller administration overhead and a less complex...

(anglicky) This thesis deals with benefits and risks of using cloud computing in public sector institutions. The thesis focuses mainly on the usage of public cloud deployment model. The thesis is divided into 4 main chapters. The first chapter presents definition and basic characteristics of cloud computing. The second part consists of PESTL analysis that describes the impact of macro-environmental factors (namely political, economical, social, technological and legal factors) on the use of cloud computing in public sector institutions. The third part presents SWOT analysis of cloud computing and its use in public sector. The fourth chapter presents a case study of the implementation of cloud computing services at The Faculty of Arts of the Charles University. The results of the conducted analysis tend to positive effects of cloud computing use in public sector institutions, presuming a proper risk analysis is done before implementation begins. Klíčová slova (anglicky): Cloud computing, IaaS, PaaS, SaaS, public sector, PESTL, SWOT, virtualisation

PlanetLab as a distributed systems testbed offers a unique opportunity for developing and testing new applications useful for future Internet. This work brings up a scheme and a solution of the problem with accessing PlanetLab by a larger group of students e.g. for the purpose of solving their courseworks. A designed system empowers its administrator to create and control virtual user accounts which provide possibility for all its users to connect to selected nodes in the PlanetLab.

This thesis deals with possible interconnections between two concepts playing a big role in contemporary business and IT world. These concepts are Business Continuity Management and Cloud Computing. In the scope of this thesis there are certain areas identified where both concepts are complement, where Cloud Computing brings new opportunities for Business Continuity Management and where could possible problems arise during particular implementation. From the BCM perspective the impact lies on IT services, from the Cloud Computing perspective the thesis deals especially with security aspects. The thesis is also aimed at the characteristics of higher education and basic differences from commercial sphere. Based on defined differences and identified interconnections between BCM and Cloud Computing, the thesis argues for usage of suitable Cloud Computing solution for higher education regarding Business Continuity improvement. The multi-criterion comparison of several Infrastructure-as-a-Service solutions stems from this analysis focusing on technical, financial, and Business Continuity aspects. The result from this comparison together with conclusions from previous chapters serve as an input for subsequent practical proposal of Cloud Computing solution and its verification against Business Continuity improvement in specific conditions on University of Economics in Prague. The proposal is also represented by strategic map.

The aim of the thesis is to describe selected consequences of informatization on the basis of three different views' critical synthesis. First view is an historical perspective focused on medialisation of information and its influence on shaping of man's thinking. On the background of technological progress are shown the milestones in changing of social reality. Another view is to describe the infromation society as a present phenomenon with its general characteristics. The last point of view is based on the hypothesis sof Global brain, which describes mankind as a network of nerve cells, connected to global computer network. Thesis is not intended to be a comprehesive overview of the informatization's consequences but it tries to explain basic issues related to information society.