ANNALS of Faculty Engineering Hunedoara

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1 AALS of Faculty Engineering Hunedoara International Journal of Engineering Tome XII [2014] Fascicule 3 [August] ISS: [CD Rom, online] a free access multidisciplinary publication of the Faculty of Engineering Hunedoara 1. Peter PEIAK MODEL OF IFRASTRUCTURE PROVISIOIG I IAAS CLOUDS 1. University of Žilina, Faculty of Electrical Engineering, Department of Control and Information Systems, Žilina, SLOVAKIA Abstract: The paper deals with model of hardware provisioning via Infrastructure as a Service in Cloud Computing. IaaS is based on a common network infrastructure and physical servers (hosts), which can be installed in various locations of the cloud. The virtualization software, called Hypervisor, creates a group of available virtual resources through physical infrastructure, which can be offered to customers. The main focus is paid on creation of a numeric model, which enables a proper sizing of cloud infrastructure for hardware provisioning according to customer requirements. Keywords: CLOUD, IAAS, SAAS, PAAS, VM, Hypervisor 1. ITRODUCTIO Cloud Computing is a modern term applied to large, hosted datacenters that offer various IT services on a utility basis. The general understanding of Cloud Computing is related to an ondemand service model by which various different resources (hardware, software, and services) are delivered over the network, which could be the Intranet of a company or the Internet when the service is ordered from an external provider [1]. The network connection is always based on Internet protocols, such as the TCP/IP protocol stack that is used to communicate between the cloud provider and the cloud consumer. Currently, there are three possible cloud service layers that can be used in combination to build a full end to end cloud [2]: Software as a Service (SaaS) offers an application, such as ERP, on demand over the network or internet. Platform as a Service (PaaS) providers offers a complete development platform including the necessary built in services, such databases, applications and midleware on demand over the network. Infrastructure as a Service (IaaS) a service offering hardware and software infrastructure components, such as computers and storage systems. A cloud (Back end) may be hosted by an enterprise or service provider and provide services (Applications, System applications and Hardware) to the clients (Front end), represented by PCs, Tablets, Smart phones, as shown in Figure 1. Datacenters can be distributed geographically to achieve higher redundancy and service independency on physical location of physical host systems. There are three deployment models defined for Cloud Computing [4]: Public Cloud that is available to clients from a third party service provider via the Internet. Public clouds provide an elastic, cost effective means to deploy solutions. copyright Faculty of Engineering Hunedoara, University POLITEHICA Timisoara 189 Fascicule 3

2 ISS: [CD-Rom, online] Private Cloud a private cloud based service, data and processes are managed within the organization without the restrictions of network bandwidth. Hybrid Cloud a combination of public and private cloud. In this model users typically outsource non business critical information and processing to the public cloud, while keeping business critical services and data in their control. The example of Hybrid Cloud is shown in Figure 2. The users are connected to the Private Cloud so that they can access critical services, such as sensitive company data and applications, with very strict Service Level Agreements. On contrary, less critical services and applications can still be provided via Public Cloud. Connection between private and public cloud is based on TCP/IP network protocols, via Internet or Figure 1. Public cloud dedicated VP network (WA). Figure 2. Hybrid cloud 2. IFRASTRUCTURE AS A SERVICE This service model delivers computer infrastructure, typically hardware, storage, servers and data center space or even network components to customer. It may include basic software within provided infrastructure. IaaS enables users to self provision these resources in order to run own platforms and applications. It is also known as Hardware as a Service (HaaS). Generally, there are several options for providing IT infrastructure via Cloud, for example as: Enterprise infrastructure as a pool of server and networking resources in order to run the applications and store their data for day to day business operations. Virtual Data Centers (VDC) a virtualized network of interconnected virtual servers which can be used to offer enhanced cloud hosting capabilities within either a private or public cloud implementation. Virtualization is an essential technology to implement cloud services. It is based on a common network infrastructure and physical servers (hosts) that can be installed in various locations and facilities. This infrastructure, with help of virtualization software called Hypervisor, creates a group of available virtual resources, which can be used for offered services [3]. IaaS provides Virtual machines to the customers and it is up to a customer, which an operation system and applications are installed. However, more advanced services can be provided on the same infrastructure as well, such as a selected database platform (PaaS), or application (SaaS), as shown in Figure Fascicule 3 Figure 3. Implementation of IaaS in Cloud and sharing infrastructure with PaaS/SaaS

3 AALS of Faculty Engineering Hunedoara International Journal of Engineering 3. SERVER PROVISIOIG The provisioning of servers was one of the first successful application of Cloud computing. This success was achieved by using virtualization as a key technology for IAAS. The consolidation of physical servers and their replacement by virtual servers simplified the hardware operations, maintenance and decreased an overall cost, bringing additional potential improvement in availability and fast service recovery. The server virtualization is based on so called Virtual Machine (VM) that represents logical server object. This simulated server hardware object behaves exactly like a physical computer or storage. It has its own virtual CPU, RAM, network interface card (IC) and hard disk and runs as an isolated operating system installation on shared hardware, called a host. The process of virtualization works by inserting a thin layer of virtualization kernel software, also called as hypervisor, directly into the computer hardware. Cloud enables the access to the defined Virtual Machines of the requested servers. These servers can be used in the same way as standard physical servers in a location. The main difference is that servers are not installed locally, but provided by Cloud via TCP/IP connection. Users are able Figure 4. Cloud with IAAS with server and storage provisioning to use their own applications, installed and configured by subscriber, but hosted on Virtual machines. As well, the dedicated servers with installed services are supported. The both possible cases are shown in Figure 4. Users can access the servers via Terminal services and work with applications in Cloud through remote desktop protocol (RDP). In the case of dedicated servers, such as database SQL server or WEB server, the local operation system of PC provides direct connection between client and server part of requested service via specific protocol (HTTP, SQLet,..). 4. DESKTOP PROVISIOIG Almost the same approach can be applied for desktop visualization. Virtual machines represent virtual desktop for users. In contrast to server virtualization, there is a difference in access layer. The users have to connect to the host computer via a specific virtualization client or through a presentation layer, such as: Citrix ICA, Microsoft Remote Desktop Protocol (RDP), PC over IP This is quite similar to Terminal services, which use the thin client or thick client to access target workplace. The main difference is that users do not share one server computer via Terminal server, but are directly connected to defined virtual machines (one to one). The management platform must deal with requirements to maintain different types of virtual desktops, user profiles and data management. Overall solution is then called as VDM (Virtual Desktop Management). Figure 5 shows a simple VDM scenario. Host servers provide resources for Hypervisor, which assigns a dedicated VMi for each requested virtual desktop. Virtual desktop runs as dedicated desktop computer with own desktop operation system (Desktop OS) and has installed the requested applications (App ij). Remote workstation (PC, Thin client, Workstation) can access the virtual desktop via terminal software with standard remote desktop protocol, for example RDP. As 191 Fascicule 3

4 ISS: [CD-Rom, online] explained, this solution is very similar to the standard Terminal services, having several desktops with separated operation system instead of sharing one computer. This approach eliminates performance problems and compatibility issues when different application can cause the conflict within single operation system. However, there is a still one disadvantage, for critical real time application or very sensitive graphical application can have significant issues due to performance of remote desktop protocols. Figure 5. Desktop provisioning based on Terminal services Figure 6. Desktop provisioning based on Virtual container approach For such case, the different model of virtualization is invented, based on virtual container system. All virtual desktops are centrally installed and stored in virtual containers, that can be transferred to any Hypervisor system or virtualization software (VM manager), which runs on the top of local operation system. The streaming protocols might be used or direct copy to the target system from USB drive/dvd is possible as well. The main advantage is that VM is started on local computer (Desktop OS1,2) and there is no need to use remote desktop protocol and compromise performance requirements. The use of virtual container keeps integrity of the image and enables a high security and software deployment. Those desktop that do not require critical response time can still run on central Hypervisor as shown in Figure 6 (Desktop OS3). 5. MODEL OF HARDWARE SIZIG The hardware sizing for needed VM resources must be in a correlation with available physical resources of the host computers. The hypervisor layer presents multiple sets of virtual hardware, which contain the same components as a regular machine (e.g., processors, chipset, etc.), such as virtual processors (VPi), 192 Fascicule 3

5 AALS of Faculty Engineering Hunedoara International Journal of Engineering virtual memory (VRAMi), virtual file systems (VFSi) and virtual network interface cards (VICi), that are mapped to physical hardware resources of host servers. The model of VM is shown in Figure 7. The correct configuration of host servers is a prerequisite for implementation of server virtualization in IaaS of Cloud. The simplified model for resource calculation is provided in the following Equations. Minimal number of requested physical host servers depends on requested amount of virtual processors: hosts1 = n m i VPij i=1 j=1 (1) Cores However, it also depends on amount of requested virtual RAM modules (VRAM), taking into consideration maximum RAM size in host and needed amount of RAM for physical server itself: μp n VRAM i i=1 hosts2 = (2) RAM host - ΔRAM where: hosts number of physical servers (recommended minimum =3); μp number of processors in host computer (sockets); Cores number of cores per processor; VPij virtual processor of VM; RAM hosts RAM size in Hosts (GB); Δ RAM RAM size needed for host computer with hypervisor itself (GB); n number of VMs; m number of virtual processors per VM The final result is calculated as a maximum from hosts1 and hosts2, but has to be rounded to the nearest higher value. As well as, we have to take into consideration necessity to support fail safe operations in Cloud environment. It means that number of physical servers must be increased with one additional host server, so that VMs can be redirected to the spare server in the case of failure of any of host computers. Therefore amount of needed physical servers can be defined by Equation 3: { } hosts => max hosts1, hosts2 + 1 (3) In addition to the requested amount of physical host servers, a size of file system is also needed for proper setting of overall IaaS infrastructure. It has to be calculated according to the following Equation: n FS = VFS + ΔFS (4) i=1 i Figure 7. Model of Cloud IaaS where: VFSi size of requested virtual file systems; FS overall size of file systems connected to physical hosts (GB); Δ FS size of file systems requested for physical host and hypervisor (GB) 6. COCLUSIOS The paper dealt with Cloud computing and possibilities to use Infrastructure as a Service for hardware provisioning. The virtualization is used as a main tool to provide requested hardware components through virtualization kernel software, also called as hypervisor. The model is based on so called Virtual Machine (VM) representing logical server object or desktop. The main focus was paid on creation of the numerical model, which is proposed as a tool for rough calculation and sizing of IaaS physical infrastructure. The proposed Equations shall be used for hosts 193 Fascicule 3

6 ISS: [CD-Rom, online] proper sizing of Cloud infrastructure in accordance with customer requirements. Based on requested amount of virtual machines, virtual processors, virtual RAM and required size of a file system, cloud provider will be able to calculate required hardware parameters, such as a number of physical hosts and amount of requested file system according to customer requirements for virtual machines. REFERECES [1.] Giriraj, M., Muthu S. (2013): A Cloud Computing Methodology for Industrial Automation and Manufacturing Execution System: Journal of Theoretical and Applied Information Technology, Publisher, JATIT & [2.] Seitz, T (2010): SAP ERP in the Cloud. Oracle WhitePaper, erp cloud pdf [3.] Bernstein, D., Ludvigson, E., Sankar, K., Diamond S, Morrow, M. (2009). Blueprint for the Intercloud Protocols and Formats for Cloud Computing In: Internet and Web Applications and Services, ICIW ʹ09. Fourth International Conference. [4.] Tao, F., Zhang, L., Venkatesh, V. C., Luo, Y. L., Cheng Y. (2011): Cloud manufacturing: a computing and service oriented manufacturing model, Proceedings of the Institution of Mechanical Engineers, Part B, Journal of Engineering Manufacture (2011). AALS of Faculty Engineering Hunedoara International Journal of Engineering copyright UIVERSITY POLITEHICA TIMISOARA, FACULTY OF EGIEERIG HUEDOARA, 5, REVOLUTIEI, , HUEDOARA, ROMAIA Fascicule 3