Although server virtualization technology is currently receiving much attention, the concept is not new. Actually the idea came in the mid-1960s, when the Giants and expensive computers of the day reached to a high processing speed but they were unable to seize the expensive computing time due to management processes that needed to be done manually by the operator. To get the best out of expensive computer processing, it was necessary to run multiple processes in parallel. Thus arose the concept of time sharing, which culminated with the idea of virtualization.

Time Sharing: This concept means sharing time, i.e., idle time between the processes are shared with other processes to streamline the system. Multiple jobs are executed simultaneously, and the CPU meets each job for a little while, one by one in sequence. The time dedicated to each job are small enough so that users can interact with each program to recognize that there are no other programs running.

In 1972, an American computer scientist, Robert P. Goldberg introduced the theoretical basis of the architecture for virtual computer systems in his dissertation at Harvard University. In the same year IBM introduced a mainframe that was able to simultaneously run different operating systems under the supervision of a control program – hypervisor.

The IBM System 370 was the first commercial computer entirely designed for virtualization, with which, the operating system CP / CMS allows you to run multiple instances simultaneously. This was followed by the IBM z / VM, which took advantage of hardware virtualization. The VM / CMS is highly regarded and widely distributed in the industry and academia. Several modern approaches to virtualization implementations are very unique for mainframe of computers from IBM.

Over the years, virtualization has begun to fall by the wayside due to creation of new client / server applications and the decline of the mainframe platform that lost power before the rise of the x86 platform. According to VMWare, the widespread adoption of Windows and Linux as the operating system on servers in the 1990s eventually established the x86 architecture as the industry standard.

Due to high costs for the purchase of a mainframe, companies began to acquire x86 servers according to demand, this is a process called low-end (several small machines doing the work of a large dedicated server). In this scenario, instead of having a high initial cost with the purchase of a mainframe, they opt for purchasing smaller servers according to need.

The impact of this new strategy was to ensure  a good deal of backlash against hardware scaling problems, and most of these servers were used for a single application. Thus, according to International Data Corporation, in each implementation of a typical x86 server, the roof of CPU usage was between 10 to 15% of the total capacity of this server.

The servers were oversized for the application that would perform, and as a result, ended up suffering the same problem of mainframes of the 1960s, that is, not all took advantage of their computing power,  and were underutilized.

Then in 1999, VMware Inc. introduced the concept of virtualization on the x86 platform as a more efficient way to operate the equipment of the platform, taking advantage of x86 servers to provide a computational structure that would enable the full utilization of computational resources of these servers.

From 2005, processor manufacturers like Intel and AMD have given more attention to the need to improve hardware support in their products. Intel with its Intel VT and AMD with AMD-V. These hardware contains features which allow to exploit hypervisors that are used with the improved technique of virtualization (full virtualization) that make it easier to implement and enhance the performance.

The sector recorded a real race for the virtualization of data centers and server hosting, in the wake of technological and economic advantages it can offer. The companies, however, should be conscious of the risk arising from plunging too quickly into cloud computing services, since virtual environments have many implications of compliance and safety.

Without doubt, virtualization creates an additional layer within the IT infrastructure, where often traditional security software, designed for physical environments, has a lack of visibility. This introduces vulnerabilities into the network, and visible gaps in the traffic between VMs. The new virtual machines that are installed automatically on the platform (especially in the case of an uncontrolled expansion of the VM) should be protected, regularly and systematically. The VMs are migrated from one physical platform to another – due to expansion of infrastructure or broken hardware – it also needs to be protected and monitored to avoid downtime during the live migration of VMs.

In addition to these internal threats, companies must protect their virtual environments also against external threats. Virtual environments can be even more dangerous than physical since the same techniques of attack and the same threats that exist in the physical layer exist in the virtual platform, where applications are not physically separated. This means that if a host server is under attack and the virtualization layer is compromised, this too can expose all the virtual machines to compromise on the infrastructure, all applications and data.

What are the best security practices for maintaining a secure virtual network?

The ideal solution must provide the same level of security present on the physical servers, virtual machines and applications:

First of all virtual machines too separate and protect the traffic between them, and hypervisor. The integration with it is important to ensure that the protection is running the hypervisor itself, not only on the virtual machine.

Secondly, the solution must proactively protect against external threats, with firewalls and intrusion prevention capabilities.

Third, to ensure unified management for both physical and virtual environments, making it easier for administrators to manage security.

It is important that the solution does all the above, without compromising the flexibility and scalability of the virtual system – security should help to exploit the benefits of virtualization, and not to mitigate them.

In addition, the solution must provide protection at all levels of security and not only at the network level. Of course, all levels of protection applied to the movement in the physical world, must also be implemented in the virtual environment.

Conclusion

Virtualization, as each new technology presents new risks for a company, incorrect implementation of security for a real environment may negatively impact on a company, exposing it to new risks and threats to security. For this reason, the implementation of the security architecture must be appropriate in a virtual environment, and knowledge of how to stay updated and protected against both internal and external threats, is a must for IT managers.

When talking about VMware virtualization,  a few years ago nobody thought about how this technology would become complex: today’s large companies and SMEs have sufficiently large virtualized environments for better security.

Today, virtualization has become a key enabler to the IT and business for companies. In the initial stage, it was primarily used to consolidate web hosting servers and IT resources to save cost and space, and reduce energy consumption. Since then, this technology has found many more possibilities of use and new applications. Companies exploit it as a way to enhance business continuity, to maximize operational flexibility, provisioning, testing, changes in management or to support disaster recovery services.

At the server level, virtualization separate (separates) the physical resources of the operating system (OS) and applications. It breaks the rigid link between hardware and software, and allows multiple instances of an operating system and various software applications to run on the same hardware support. In other words, virtualization extracts and organizes the operating system and applications software in a virtual machine (VM). The entire “package” of virtual hardware – CPU, memory and network, OS and applications – becomes a single software files (file). The machines are hardware independent and can be managed as documents, with the convenience of copying and pasting.

The VM monitor, or hypervisor provides access to physical resources to multiple virtual machines or guests. Hardware resources are dynamically allocated to groups for workloads, while the VMs are isolated (they do not influence each other) and encapsulated (easy to store, move, etc.). This allows you to create a series of savings, thanks to less use of hardware, electricity and space systems and infrastructures. At the same time, it reduces costs related to personnel, as well as the complexity, implementation time and management.

One way to understand the impact of virtualization on the IT industry is to compare it to the Electronic Banking : once the money is deposited in the physical system and converted into bytes, it increases the speed of business. The money can be moved in all parts of the world at very high speeds. Transforming physical feature information (bytes), virtualization brings a new level of efficiency and flexibility in IT. In particular, virtualization makes it possible for faster and more flexible provisioning and managing of the entire IT infrastructure.

With virtualization, you can reduce the actual costs and boost productivity, resulting in savings in terms of number of servers, carbon footprint, power consumption and cooling requirements. If you are  trying to protect the environment, improve the reputation of the brand or enhance competitiveness, virtualization is a very interesting proposal.

Virtualization allows organizations to leverage the resources of the system by consolidating applications on fewer physical servers. As the demand for infrastructure in the data center changes, in response to peaks in traffic, the physical resources that are not immediately required are switched off automatically, ensuring more efficient use of resources.

To make a successful virtualization implementation, CIOs need to know how to get what they want and determine if the technology is good for business. Within any organization, disruptive or revolutionary initiatives have the highest probability of failure. Instead of approaching virtualization as a gradual evolution, companies can increase their success rate.

Migrate To A Virtual Environment

Virtualization is becoming a commodity, and should be considered as such. With the maturing of the market, CIOs are better prepared and better understand the potential and limitations of technology and what they can expect from a service provider. And it is responsibility of the supplier to provide details concerning best practices, and companies should not refrain from asking all necessary questions.

Determining what percentage of the load of a company can realistically be virtualized is a first thing to understand. We rarely see companies that migrate immediately most of the workload in a virtual environment, it is common practice to start with the less critical activities, experience with the platform and then increase the loads and also include mission-critical applications.

And workloads should migrate further once you have confidence in the platform and the support offered by the cloud computing service provider.

Rather than considering virtualization as a standalone project, companies should look more closely at the internal processes that may be impacted by the adoption of virtualization technologies. Otherwise, the risk is that, customers consider that the expected benefits of virtualization, especially in terms of improved IT agility, do not become reality. In other words, often the main obstacle to the successful adoption of virtualization is not the technology, but the processes that surround it.

This includes provisioning and changing the management processes. Each application involved may compete for processing resources and it is important for companies to adopt software that provides greater visibility in the architecture to determine how IT applications are operating. Increased visibility enables administrators to anticipate conflicts and monitor performance to ensure that critical applications receive the priority they deserve and that performance levels are met.

LVS (Linux Virtual Server) is a set of utilities and patches for the Linux kernel that allows the creation of a single virtual server from multiple nodes, all in load balancing and high availability by eliminating the weaknesses of the infrastructure ( SPOF ) If a node falls, in fact, the service is not interrupted.

With this system the end user will connect to a service (HTTP, FTP, DNS, VoIP, etc …) as if it were hosted on a single server, when in fact there is a whole infrastructure behind the operation of that service, and management of the latter is entrusted to its LVS that deals with requests for it to route to each node and will actually process the request and return the result, all following one of many sorting algorithms implemented in LVS .

The scalability of this system is achieved through the ability to increase or decrease necessary knots, no need to interrupt services, the same thing for high availability when the system detects a malfunction of a demon or a whole, this node is temporarily removed from the nodes available in which it process the requests.

Operation And Forwarding Methods

Let’s see how LVS works in detail. LVS operates through three-layer architecture ( tier-three architecture ) :

The load balancer (obviously redundant) that receives requests from users and redistributes them to various nodes that make up the cluster, also monitors the proper functioning.

All the servers that make up the cluster (nodes) and that process actual requests that are forwarded by the load balancer (for example, can return a web page).

A shared, centralized storage so that data is uniformly available from all nodes at the same time, then without any discrepancies.

The Load Balancer Can Route Requests In Three Different Ways:

Virtual Server via NAT (VS / NAT) : With this method all requests from load balancers (both incoming and outgoing), go to the next chapter to describe in detail all the steps.

When a user accesses a web service managed by cluster, the load balancer receives a packet on the IP of the virtual cluster.

At this point the load balancer examines the destination address and port of the package, if they correspond to a virtual service in the rules of table of the virtual servers ( virtual server rule table ) is selected physical server to which it process the request according to a certain scheduling algorithm and the connection is added to the hash table of connections. At this point, the destination address and port are rewritten by the load balancer to be sent to the physical server selected above.

The request is finally processed by the physical server.

When the response packet is sent back, the load balancer rewrites the source of IP changing from one physical server cluster virtual IP.

The end user receives the result, and once the connection is terminated (or has gone out) is deleted from the respective hash table of connections.

Virtual Server via IP Tunneling (VS / TUN) : Unlike the method VS / NAT in this case, the load balancer sends the package containing the client request to the server via IP tunneling and the physical server, once processed the request, send it directly to the client without going again from the load balancer. This technique is used primarily for geographical clusters.

Virtual Server via Direct Routing (VS / DR) : This method assumes that the load balancer is physically connected with all the physical servers (such as through a network switch). The cluster’s virtual IP address will be shared by the load balancer and all the dedicated server through a network interface (aka, non-arping and loopback) configured with the cluster virtual IP and load balancer will have a standard interface to receive all requests from the outside. Upon receipt of a package, the load balancer will change the MAC address of the destination of choice for physical server data processing and once processed, the physical server will send the response directly to the client.

Balancing Algorithms

Now that we have analyzed the different methods of forwarding the requests, let’s see what are the different algorithms for balancing that we can use with LVS.

Static :

- Round Robin
- Weighted Round Robin
- Destination Hashing
- Source Hashing

Dynamic :

- Least-Connection
- Weighted least-connection
- Never queue
- Locality-based least-connection
- Locality-based least-connection with replication scheduling
- Shortest expected delay

For convenience I will use the description of algorithms, then we will begin with the classic Round Robin and its variation ( Weighted Round Robin ).

This algorithm works by simply changing the physical server to send the request to each of them, gradually . So if you arrive at the required load balancer and 4 had 3 physical servers currently running in cluster, the first request would be forwarded to the first physical server, the second to second, the third to third and fourth again at the first.

The Weighted Round Robin can manage the priority of physical servers, giving a different weight , so if we bought a new server that is supposed to be the most powerful of the old and thus able to process more requests than others, we can give it a chance higher than the requests that are sent to this new server from load balancer. For example if we had three physical servers in the cluster, two of which are less powerful and a more powerful server may assign to the two less powerful than a priority of 30% each, and the more powerful server as a priority by 40%.

The scheduling algorithm least-connection to check which server has the least number of active network connections and forwards the new request to the server that has not, unfortunately, however, is efficient only if all servers have the same power.

The scheduling algorithm shortest expected delay is based on the calculation of how could the server process the request more quickly , this calculation is given by (total connections +1) / (power on the server). Again the power of the server is given the weight that has over the others.

All for now, do not miss the second part of this article that will focus on ‘high availability’.

Development of a segment of virtualization as a whole is in full compliance with the extended version of the law, which describes the time variation of the public interest in new technologies and their level of actual use. However, in contrast to SOA, the use of which still lags well behind the projections of three-four years ago and the prospect is still not very clearly visible, with respect to virtualization, it can be said unequivocally: a public frenzy around the topic significantly decreases, but the scope of use of these funds is growing rapidly, that can fully describe the adage “less noise, more business.”

Server Virtualization

In recent years, issues of virtualization focused almost exclusively on the problems of server consolidation. This trend will certainly continue to evolve, both in terms of expanding the number of customers, and the depth of penetration of virtualization on IT infrastructure. This trend is seen quite clearly, and so we can fully agree with analysis of the IDC, which in the autumn of 2009, noted the passage of the Indian market funds of Virtualization on the stage of “Learning Opportunities” to the stage of the extended use of virtualization of individual servers to the creation of virtual environments at a data center.

Interests of customers quickly shifted to the construction of an integrated virtual infrastructure and management. Superficially, this is reflected in the fact that the term “hypervisor” which was a hit in the articles on the topic of virtualization. At the same time, an increasingly significant role in this market are beginning to play companies that do not deal with hypervisors, but have a very respectable position in the field of IT infrastructure management. With the accumulation of experience in the application virtualization customers have increased confidence in the technology, resulting in markedly accelerated the transfer of business-critical applications and services and start to master the dynamic model of virtual environments rather than static.

However, despite the fact that virtualization has long been recognized by leading trend of the IT platform, yet to be understood that the formation of this segment (in terms of penetration of this technology in the IT systems of customers, on the one hand, and the balance of power in the market, on the other ) is still far from complete. Although many companies have used the server virtualization (maybe even in majority) of its Level (percentage of virtual servers in the server infrastructure), variously estimated at less than 15-20%. It should be borne in mind that virtualization are first and foremost the least business-critical tasks.

Here we must pay attention to the fact that while the scope of virtualization for many years in the field of attention the world’s leading analysts, until recently, experts have explicitly avoided making traditional quantitative assessment of vendors’ positions in the best case, calling the size of the market as a whole. The situation changed only with studies in the middle of this year: Gartner first unveiled its “Magic Quadrant” market of server virtualization. Commenting on this report , we noted that even the overall assessment of the situation clearly shows the incompleteness of market formation and, moreover, casts doubt on the validity of the formulation of the question of the existence of the IT segment as a separate part of the market platform software.

It seems that quadrant shows that VMware has created a gap with a reserve of strength that talk about serious competition which is not necessary. Yet the fight for the championship still to come, and VMware will be the main competitors of Microsoft and Oracle. And not just because it is a major platform vendors. The fact that they offer different (different from VMware) virtualization strategy and try to play on the field against the rules, but on their own.

Recall that VMware believes virtualization independent segment, infrastructure software, which should push the traditional OS in the background, or even completely removed as unnecessary. Microsoft holds the opposite opinion, considering the only virtualization as part of the OS. Well, Oracle is betting on virtualization software is not at all, and its software in the first place. In the paramount applications (of course, their own), and virtualization is regarded as a means to support them.

Here it is useful to recall that virtualization is applied to IT. After all, IT was originally built on the principle of virtualization of computing processes, and it turns out that virtualization technology – it is something like “butter oil”. However, this paradox can be resolved if we take into account here such a formulation, found a few years ago in one of encyclopedias: Virtualization in IT – this means that it extend the capabilities of traditional IT architecture. ” This implies an unexpected conclusion: as soon as these funds become part of the traditional IT architecture, they no longer belong to the category of virtualization.

PC Virtualization

As it is known, the use of virtualization to the x86 architecture computers began in the late 1990′s with a PC. Dedicated Server technology appeared after two or three years, and quickly took the lead in terms of demand for market, relegating the problems of the PC in the background. However, in the second half of 2009, became noticeable growth of interest in virtualization personal computers. You can find a number of reasons for this trend. The first is, of course, have to say about a number of objective points, such as raising the overall level of confidence in virtualization, coupled with the desire of customers to reduce operating costs and ensure the work of the expanding range of mobile users. But in addition, be sure to note such factors as the beginning of mass transfer of enterprises on Windows 7, which requires to solve the problem of support for this OS legacy applications.

It should be noted that virtualization PC is very difficult technical direction, and in no way be regarded as a “simplified” version of server technologies. Moreover, in many aspects of virtualization, personal systems are much more complex than with servers. And it can be seen even by the fact that the issue of desktop virtualization involves several different (often overlapping) organizational and technical areas.

But to understand all this variety, there are two main types: client and server.

First in general terms, all computations are performed on the PC (including a fully autonomous), in the second case – on the server and workstation (or even more accurately – user terminal device) performs only functions of the user interface. The classic way to implement the first option – these are the client virtual machine, which begins with the x86-virtualization (a pioneer in this direction VMware WorkStation represented now at version 7.1.4). The second option – the architecture of Virtual Desktop Infrastructure (VDI), which has long been in the focus of IT community.

We will not delve into other virtualization solutions for the PC, just note that among them, there are many different approaches and combinations (eg, application virtualization, management of client virtual machines from a server).

The fundamental difference here is that the client virtualization is aimed at “correcting” deficiencies desktop OS, primarily to support legacy applications, reliable operation of the applications, while the goal of VDI – reducing IT costs and support for mobile corporate employees. From this it is clear that the client virtualization is still more to do with solving problems of tactical nature, while the VDI can be classified as strategic.

The term VDI appeared in the IT market a few years ago, and many vendors have already stated that they have a VDI-making. However, until recently, the question of the prospects of this area remained dug: leading analysts talked about the practical absence of demand from customers. However, in 2009, it seems, there was quite a decisive change for the market to VDI: the process of implementing this architecture, “went”, and in the world, and India. Among the reasons for this include improving themselves VDI-making, increase capacity and reliability of the Internet, as well as the need for companies to reduce operating expenses (generally considered to be almost proven that VDI does not save the capital costs).

A clear reflection of prospects VDI has, in particular, a significant correction of Microsoft’s position in this matter. If the corporation had always emphasized its skeptical attitude toward the technology (although it had in its arsenal of such funds), then in March of 2010, it declared the intention to significantly increase its activity towards VDI. It is noteworthy that for a successful fight against VMware in this area Microsoft collaborated with his longtime strategic partner, Citrix.

It is significant that it is the VDI issues were the focus of the past, the conferences of all three major players – VMware (it held a special event just for that category in the submission of a number of projects implemented in India), Microsoft and Citrix. We also note the increased number of publications in the media about the experience of the VDI.

From virtualization to the clouds

One of the most notable differences from earlier last year in India – the beginning and increasingly moving from a pure virtualization subject to cloud Affairs (Cloud Services). In fact, even the first representatives of the vendors avoid the word “clouds” in their presentations, and local news, explaining it very simply: “No need to scare and confuse the customer, let them first become accustomed to virtualization.” All of this was evident by publications in professional mass media: the clouds in the articles and news were already present continuously, but they were mostly stories that were not about our local affairs, but the foreign ones. Outwardly, it looked even quite funny: the impression that the same vendor (eg, VMware or Microsoft) at home and at us – they are two different companies …

This year the clouds began to talk about (in our country at home, they talked about this for a long time) and all other providers of virtualization. As usual, the most audible voice was Microsoft, which presented its vision for the transition to the cloud. Such migration should be carried out in three major steps: from the traditional data center to a public cloud, and in this scheme need to pay attention to a very important stage of transition from a virtualized data center to a private clouds (some other experts equate these concepts ), which consists in a fundamentally important point – the use of the service model in the relationship between IT and business.

In this case, we  made a number of tips on preparing for the introduction of cloud virtualization systems:

• Implement virtualization.
• use, scalable data center equipment.
• Use a single management system for both physical and virtual resources.
• Design of IT services based on architecture resource pool.
• However, it should be noted that the virtualization technology directly cover only the basic part of the cloud theme, that sphere of clouds, which belongs to the category IaaS (Infrastructure as a service). And although in the short term the practical work of Indian enterprises with Cloud Computing is likely to be concentrated in the direction IaaS, nevertheless, have a business in the coming season, platform vendors will begin to psychological preparation of the customers for the future use of the model PaaS (Platform as a service).

The technique of virtualization is to create a virtual version of a hardware resource normally provided physically, in particular the x86 virtualization is the creation of a virtual version of a resource belonging to a system with x86 architecture. Any hardware or software resource can be virtualized, so you can have virtual versions of operating systems, memory, disk.

This technique then allows the execution of one or more operating systems and associated software on a single computer without rebooting the system, and with the advantage of creating a secure environment where they are monitored and carry out the instructions of the virtual system.

Virtualization is made possible by the excessive size of the hardware architectures in use today than those that are normal and most common uses of computers. The uses of virtualization is probably the most popular operating system virtualization to create virtual servers for test server to support the development, or creating websites. In the context of virtualization, there are two different systems, host and guest. The host system is the system that is running a virtualization software that creates a high level the different virtual machines, which function as if they were normal programs, communicating with the hardware only indirectly, through virtualization software that works at low level. The operating systems running within each virtual machine guest are defined.

Types of Virtualization

It is possible to distinguish different types of virtualization, depending on how you run the virtual system. In particular, it distinguishes between:

Full virtualization also known as native : The characteristic of this mode is the presence of a hypervisor that implements the separation between the host system and the physical hardware of the machine, creating an insulation between the two domains. It is also identified as virtualization software, and a well-known example is the implementation of VirtualBox;

Paravirtualization : The control software exports an API to the hypervisor, which allows access to different hardware resources to the host system. This mode is implemented by the KVM virtualization;

Emulation : The control of software emulates the underlying hardware for the host system. This type of virtualization is slower than the other two, since all operations at the level of machine language must be translated by the instruction format of the host system to the guest system.

The virtual extensions from Intel and AMD

Intel and AMD have independently developed virtualization extensions to the x86 architecture, natively integrated in the set of instructions from their CPU, and these extensions are not fully compatible with each other, but support roughly the same instructions. The added value of this selection technique is that the Intel / AMD with support for these extensions allow for virtualization management in hardware, resulting in gains in performance, because a virtual machine that has to emulate a hardware for a host operating system with access to this set of instructions on the CPU, will reduce the computational load on the CPU and no longer having to emulate the entire system in software.

The virtualization extensions developed by Intel for the x86 32-bit (IA-32) and 64-bit (EM64T) is available on all Pentium 4 6×2, Pentium D 9×0, Xeon 7xxx, Core Duo and Core 2 Duo except for the T5200, T5500, E4300, E4400, E4500 and E4600.

AMD processors that use the Socket AM2, Socket S1, and Socket F AMD Virtualization support, including the Athlon 64, Turion 64 and Opteron.

KVM and QEMU Virtualization to 100% in Linux

KVM (Kernel-based Virtual Machine) is open source software, which allows for a full virtualization solution for Linux on x86 hardware that supports virtualization extensions such as Intel VT or AMD-V.

Each virtual machine has its own private virtualized hardware, such as network card, disk, graphics card, without going to touch the guest system. KVM is a kernel module, in a separate part that acts as a core infrastructure virtualization, and then the specific part for the guest of Intel or AMD CPU; modules are intel.ko-kvm and kvm-amd.ko . The module includes a char driver who is responsible for directing the control of I/O from the guest kernel to the host system.

The KVM package includes a modified version of QEMU which makes use of this form. QEMU is a processor emulator that is capable of emulating several hardware architectures, including x86, x86_64, ARM, SPARC, PowerPC, and MIPS.

The system hardware is emulated guest dynamically by examining the code executed within the virtual machine and translate it into instructions comprehensible to the guest machine. Modified QEMU is much faster and with higher performance, because of the KVM uses processor extensions for virtualization and the original emulates the ioctl.

The host, however, is bound to the x86, x86_64 and PowerPC. In the case of the x86 architecture there is an accelerator (kqemu) able to avoid the dynamic translation of instructions, allowing you to achieve performance that is around 30-50% of those of the guest.

Using KVM, one can have multiple virtual machines running simultaneously. The kernel component of KVM is included in mainline Linux kernel since 2.6.20.

Preparing for Installation of KVM

From all this it is clear that KVM is necessary to run the CPU support virtualization natively. You can test whether there is support in a simple way from the console with the command

root @ User-VirtualBox: ~ # egrep-c ‘(vmx | svm)’ / proc / cpuinfo

If the answer is 0 means that the CPU does not support hardware virtualization, but if the answer is a virtualization is supported , but you must verify that the BIOS option is enabled for virtualization or not. Some computers have disabled the possibility to use the virtualization extensions of the processor, in this case, go into the BIOS and enable the use.

Installing KVM requires some precautions, especially for the amount of memory that will be allocated to the host system. Indeed, there is a limit to the amount of memory you can dedicate to the virtual system, and adopted at a maximum of 2 GB by installing a 32-bit kernel, over 2 GB with a 64-bit kernel.

This choice implies, therefore a 64-bit virtual machines can accommodate 64-bit and 32 bit, instead of a 32-bit system is limited to only being able to accommodate 32-bit virtual machines. Obviously a 64-bit kernel requires a processor from the same surface area, which can be verified very simply with the command:

User-root @ server1: ~ # grep ‘lm’ / proc / cpuinfo

lm stands for long if this command mode does not provide any response means that the CPU is 64 bit. Instead, to verify that you are running a 64-bit kernel can use a command like the classic;

User-root @ server1: ~ # uname-m

the result indicates the type of processor, in particular, the term x86_64 from information that you are using a 64-bit kernel, while the abbreviations i386, i486, i586 or i686, indicate that you are using a 32-bit kernel .

Installing KVM

Installing Ubuntu in a 10.10, as always, is helped by magical apitude, which will install and prepare everything you need:

User-root @ server1: ~ # apt-get install libvirt-bin kvm qemu-ubuntu-vm-builder bridge-utils virt-viewer

Specifically, the packages that are installed with this process are described below:

• qemu-kvm is the backend, that is the real core that creates and manages virtual machines;

• libvirt-bin daemon provides libvirtd required to administer instances of using kvm and qemu libvirt ubuntu-vm-builder is a command line tool, very powerful, used for creating virtual machines;

• bridge-utils provides a bridge between a network and the virtual machine to allow communication with the real external world;

• virt-viewer, you see instances of virtual machines

After completing the installation process it is necessary to have an image of the host system to boot. To create an image, simply use the command qemu-img that is in the directory / usr / local / kvm / bin /:

User-root @ server1: ~ # / usr / local / kvm / bin / qemu-img create-f qcow
filename.img 3000M

after which you can launch and use QEMU:

User-root @ server1: ~ # / usr / local / kvm / bin / qemu

In conclusion

Virtualization is a very complex and extensive that it cannot be exhausted in a few lines. We have just taken a little ‘dust from one topic that often scares in an excessive way, because it is relatively young, and because often, virtualization is introduced as a concept, we speak of the creation of virtual systems, but do not expose those added values and benefits of using a virtual system in daily use.

The return on investment is due to the use of a virtual server, thanks to excessive size of current systems than those that are with the daily workload. Virtualization allows you to use hardware resources more efficiently, to create virtual networks internal to a single computer, to test software, attacks and their methods of defense in a safe environment without compromising the guest.

Also the possibility to migrate a virtual machine from one guest to another, in a simple way you can start services that would normally take longer because of the need to find a dedicated server hardware, thus the mobility of users and the portability achieve greater added value.

I personally think that the ability to run applications and systems are no longer supported, developed for different hardware and thus have no need for a high number of physical servers in addition to the charges involve in a significant investment in space, and still being able to eliminate the dual boot and to use as Windows and Linux simultaneously on the desktop and laptop to communicate the two systems as if they were on a real network, has paid off all efforts to push virtualization to the degree of maturity that has reached today.