Imagine a typical data enterprise center with many servers. The majority of these servers sit idle as the workload of the enterprise is distributed among a small number of servers. This results in what can be considered a waste of resources, as these systems are not at work and yet will use power, require maintenance, and even cooling. This is a problem in many work environments today, and this is the exact kind of situation that server virtualization intends to solve. In this chapter, an exploration of server virtualization is done. The concept is explained, and so is the benefit of the approach.
Components of a Server
A server, basically, is also a type of computer. However, depending on the type of server in question, they are always set up differently from the average personal computer used by the average consumer. All the different kinds of hosting all involve the use of dedicated servers. However, the difference between shared, cloud, and VPS hosting is that the servers are organized and structured differently. The key components of a server are outlined below.
There are different components in servers; some are basic, while others are optional. They include the following.
Motherboard
The most basic explanation of a motherboard is that it is a circuit board that ensures the connection of all server components. This is where the heartbeat of the server is, and most consumers know little to nothing about it. The most important point to note when it comes to the motherboard is that it dictates the type of CPU, number of hard drives, and the amount of RAM that is needed for connection to the server.
Central Processing Unit
This component is also known as the processor, and it works like the brain of the server. It regulates performance but is not the only component that matters when it comes to performance. However, the importance of the CPU is trivialized. It is important for even the average consumer to understand the importance of processors and what makes a good CPU. You need to get enough information so that you know if you are getting a good deal on a central processing unit. Different hosts may offer outdated models or consumer-grade processors instead of the current gen-server grade processors.
Random Access Memory
Servers cannot be complete without memory, especially if the hosting of websites is involved. In the server, memory refers to the RAM and not the hard drive. RAM is similar to the human brain’s short-term and is critical for the server’s performance and the amount of memory that will need to be scaled up to meet the needs of the host. Apart from quantities, quality should also be considered when talking about RAM. There are four RAM generations currently, and the newer versions run faster than the older ones. To ensure that you have the best, look for the latest RAM technology as this will result in the highest value for your money and the best performance.
Network Connection
The network connection is yet another important component of servers. Servers are often connected to ports whose speeds are set by the host and can vary. Most of them start at 10Gbps, and others can go as high as Gigabit connections.
Hard Drive
The hard drive is yet another component of a server. The ultimate hard drive today is the SATA drive as they offer reliability and stellar performance. However, as is the case with many technological inventions, there are already better inventions threatening to take the place of SATA drives, for instance, Solid State Drives. All servers are beginning to embrace SSDs because they offer superior speeds for reading and writing, and they are highly reliable. Getting an SSD means a move towards increased server performance.
Graphics Processing Unit (An Optional Component)
Traditionally, GPUs were used only for gaming and graphic interfaces. Over time, however, these components have found their way in servers. They are accessed through a command line or terminal. There are other high-end GPUs that today are used in place of CPUs. Most servers, however, do not consist of GPUs. The ones that will be putting them in place are those that deal with artificial intelligence and machine learning especially.
What Is Server Virtualization?
Server virtualization is a process through which software on a physical server is aided to create a number of virtual instances that can run independently. On a dedicated server, the machine has one operating system. However, with a virtual server, one machine can be able to run multiple instances, all of which will have independent operating systems. In this process, a physical server is taken, and the virtualization software helps to partition it and divide it so that it created what was referred to above as virtual instances.
The entire system is dedicated to one thing, and thus, the server can be used in many different ways. So, unlike in the past, before virtualization was mainstream, an operating system does not require a physical platform to host an operating system. A hypervisor is used to share the hardware of the host with the individual virtual machines. This technique, therefore, allows the sharing of resources, which enables organizations to reduce the cost of running a lot of physical software and reduce their data center hardware footprints.
Another way through which the concept of server virtualization can be understood is through the host/ guest paradigm. Every gust will run on a virtual imitation of what would be considered the hardware layer. The guest OS runs without modifications and also allows the administrator to play the role of creating guests that use a different OS. The guest, in this case, does not usually know anything about the operating system of the host.
The concept of data virtualization only hit the waves recently, and yet it has been in the oven for well over 50 years. IBM was a pioneer organization when it came to the virtualization of system memory. This would eventually act as the precursor to virtualization hardware. IBM created the VM/ 370, a propriety operating system. This operating system level of virtualization does not have much significance beyond mainframe computing, but even though its simplicity, it developed to the z/ VM, which was the first virtual platform for severs that was used for commercial purposes in the market.
Today, server virtualization has become a norm, and the concept became dominant in the IT industry. Several companies are moving towards full virtualization and cloud-managed information technology ecosystems. This trend of virtualization’s popularity came to life in the 90s with the release of the VMware workstation by VMware. The VMWare workstation was a savior that enabled the virtualization of x86/ x64 machines and architecture and popularized virtualization. It became possible to run Windows, macOS, and Linux on one host hardware, and, therefore, over the past two decades, virtualization of servers has served an important role in shaping the IT infrastructure market.
For virtualized server platforms, it is necessary to have a vendor or host hardware available. The hardware, in most cases, is usually a server that requires software as described above. The software is called a hypervisor. The role of the hypervisor is to present the generic virtualized hardware to the operating systems that are installed onto it. The hardware included all the components needed to start the operating system, including the CPU, network drivers, hard disks, SCSI drivers, and memory allocations. The hypervisor, therefore, manages the resources of the host and allocates the same resources to every virtual machine that depends on it.
Virtualization can happen in either Windows, Linux, and Aix operating systems. Even more interesting is the fact that manufacturers are now offering virtual appliances of hardware devices. For example, Network Load balancers were traditionally physical devices in a rack. Today, however, things have changed, and they are many times virtualized. There is more power in host hardware, so offering virtualized dedicated appliances is quickly becoming commonplace.
There are several types of hypervisors. Below, we discuss information about hypervisors in detail.
As you may have already gathered, the hypervisor is the primary software that is meant to enable virtualization in servers. There are mainly two types of hypervisors:
Baremetal
This is what is commonly referred to as the Type 1 hypervisor and is often installed directly on the host hardware. Directly, this hypervisor manages all the resources of server hardware that are installed in the bare-metal tin. Every hardware resource in this hardware is then allocated to virtual machines through the Hypervisor Operating system.
The Type 2 Hypervisor
This hypervisor runs directly on top of the conventional operating system. It does so as an application or process. It virtualizes the hardware resources found in the conventional operating system. Interestingly, this type of hypervisor is common in non-production environments, and an example is the VMWare Workstation and Virtual Box.
Today, the VMware company has managed to keep every other manufacturer busy such that it has dominated the virtualization industry. So the software has ended up in use in many of the world’s data centers. A giant in IT, Microsoft, produced its own version of the hypervisor-Hyper-V back in 2008. This hypervisor comes up with almost all Microsoft server operating systems, but recently, there has been a newer addition as the package comes bundled with Windows 10 Professional. The open-source community has its own hypervisor, known as Xen. Xen is a creation of Cambridge University during the 1990s. However, it has continued to play a vital role in the world of virtualization today. It is, for instance, Amazon’s virtual platform for cloud-based Amazon Web Services. Since Amazon is winning in the cloud ecosystem, other companies use Xen as a commercial product.
Server virtualization is not just a thing for software manufacturers. In fact, today, IBM, a company that manufactures its own hardware is a major manufacturer of hypervisors. The platforms of IBM, including System I, System Z, and System P, use the para-virtual hypervisor. The guest virtual machines have prior knowledge of each other and the resource requirements allotted to them through their host. The hardware resources of the host are divided and allocated to the virtual machine. Through this sharing, every partition knows of the partition requirements of the other, and every server has the least minimum hardware designed.
There is also operating system virtualization. At this level, virtualization works differently. There is no basis on the host/ guest paradigm. Instead, the host runs an operating system kernel as the core and distributes the functionalities of the operating system to the guests. Guests then use the same operating system as the host, but it is allowed to use different distributions of the same system. Distributing architecture like this eliminates the system calls between layers, thus reducing the overhead of CPU usage. Each partition also remains isolated strictly from a neighbor so that security breaches and failure in a partition does not affect other partitions. Common libraries and binaries are shared on the same physical machine, which allows the operating system level virtual server to host an infinite number of guests all at once.
Server virtualization is part of an overall trend toward virtualization in IT involving enterprises. It works alongside network virtualization, storage virtualization, and management of workloads. Server virtualization is a component in autonomic computing development, which aims to enable the server to manage itself based on the perceived activity.
Types of server virtualization There is more than one way through which virtualization can be achieved, apart from paravirtualization that has been discussed. The ones that will be discussed below are:
- OS level virtualization
- Paravirtualization
- Full virtualization
These share a few common traits, for example, they all have a physical server that is referred to as the host, and the virtual servers are called guests. The virtual servers exhibit behavior similar to physical machines & every system uses a different approach for the allocation of physical server resources for virtual server needs.
Full virtualization
Full virtualization makes use of the hypervisor software. This hypervisor directly interacts with the CPU’s and disk space’s physical servers. The hypervisor serves as a platform that can be used by the operating systems of the virtual servers. The hypervisor does the work of keeping every virtual server independent and even unaware of the other virtual servers that are running on the same machine. Every guest server runs an operating system, and they do not have to be the same. One could be utilizing a Windows operating system, while the other operates a Linux operating system.
The hypervisor also monitors the resources of the physical server. The hypervisor relays resources to the appropriate virtual server from the physical machine. The virtual servers, at this time, are running applications. The hypervisor, as an application, has its own processing needs, and as such, the physical server reserves some processing resources and power that ensure the running of the hypervisor. If there are no reserve resources, then the overall performance of the system can be affected, and the speeds become slower.
Paravirtualization
As a concept, a paravirtualization is a different approach from the full version. In paravirtualization, the guest servers are aware of the existence of each other. The hypervisor in this type of virtualization does not do the kind of processing power needed to operate a guest operating system like in the full virtualization model. This is because there are interactions and recognition of the operating systems that are within the server without discrimination of one of them. There is a cohesive way of working here where the system is involved.
Operating system virtualization
This type of virtualization does not use a hypervisor in any way. The capability to virtualize is already part of the operating system. The operating system, in this case, performs the functions of a virtualized hypervisor. There is, however, a limitation to this approach. Every virtual server in this setup remains independent of the guest servers within the network, and there is no way that is operating among different operating systems. The environments in which the guest OS operates should be similar. As such, this type of environment is called a homogenous environment.
There is really no type of virtualization that is better over another. The choice to use usually depends largely on the needs of the network administrator. If the physical servers of the administrator run on the same operating system, then the operating system type of virtualization may be appropriate as these systems will be efficient and faster compared to further approaches. If alternatively, the administrator runs different servers on a variety of OS, then the network administrator may resort to the use of paravirtualization. However, there is one disadvantage that may come with using para-virtualization, which is lack of support. Compared to the other types, this is a relatively new type of technique, and, therefore, only some organizations offer materials for paravirtualization. Many organizations mainly back the use of paravirtualization. However, paravirtualization is quickly taking over and may eventually replace full virtualization.
Benefits of Server Virtualization
There are benefits to using server virtualization, and it is no wonder that many organizations invest in it. There are reasons that address technicalities, while others are purely based on financial motivations. Below, we outline the benefits of using server virtualization.
Through the method of consolidation, virtualization helps in conserving space. Each server is dedicated to one solicitation. However, should many applications only make use of a minor quantity of electricity for processing, it is possible for the administrator of the system to combine many computers into one server that can run in different virtual environments. This can especially be helpful and beneficial for companies that have multiple servers, as it will significantly reduce or eliminate the need for servers.
This technique provides a loophole through which companies can tend to like termination, all minus buying more components. Redundancy is when only one app is run on different servers. Often, it is practiced as a way to ensure safety such that if one server does not work well for whatever cases, then the other that is running this place can conveniently be a replacement. Through redundancy, there is a reduction in the service. It is not sensible to construct two servers (virtual) that perform the same presentation on a real server. In such a case, a crash in the server would mean that two virtual servers also fail. In many cases, people working within the system have the tendency to make redundant virtual servers on real technologies.
Virtual servers give structures that are not only independent but also isolated so that programmers are able to test new operating systems and applications. Instead of buying physical machines, a virtual server can simply be created on the existing machine by the network administrator. Virtual servers are usually independent of the other servers, which gives the programmer an opportunity to run the software as they need without worrying about the effect it will have on other applications.
Server hardware eventually ends up obsolete. This creates further problems because, usually, switching across two differing systems proves to be not easy. Systems such as these can be referred to as legacy systems and offering services provided by these. These outdated systems could be the answer needed for proper functionality. In such cases, the obvious and most practical thing the system administrator can do is to create a virtual account of the hardware on a server that fits today’s context.
When looking at this approach like it is from the application, everything remains the same at the very core. The tasks will work the same way they would if they were still on the preliminary hardware. The company can, therefore, buy time for transitioning to new processes without having to worry about the server breaking down. This can especially be beneficial in cases where the corporation that fashioned the original hardware ceased to be, and so, it may be impossible to fix broken equipment.
Also, migration is a trend that has come with virtualization and is, by extension, the advantage or benefit of using virtualization. If you have the right software and hardware, then it can be possible to physically remove the network of a physical machine from one to the additional. Formerly, this stood probable but merely if the two bodily technologies run on the same computer technologies that are needed, in this case, to ensure proper functionality. Today, it is possible to rove virtual servers across many different machines, even when the machines are processed rather differently due to differences in hardware. The only condition that remains is that the processors must come from the same manufacturers.
These servers help in cost minimization within enterprises. This reduction happens because virtualization helps to increase the utilization of already existing resources, and it is an efficient solution for small to medium-scale applications. As a technology, virtualization is used as a cost-effective way of providing web hosting services. Companies will acquire much less hardware for new infrastructure, and older hardware can simply be migrated to new and more efficient hardware. This equally benefits the data centers, as there will be less power and cooling requirements and reduces the data center footprint, thus reducing the overall costs associated with managed service provision.
Yet another benefit associated with virtualization is functionality. The key functions include the ability to roll back changes, which eliminates the need for the many requirements that were associated with rebuilding a network from scratch. Management features such as Cloning, vMotion, and Fault Tolerance changed how administrators could increase infrastructure uptime while offering the best service level agreement to customers. As a result, network administrators can deploy new virtual machines almost instantly through the use of templates. Server provisioning has equally improved. Now, it is possible to build a new virtual infrastructure from scripts. With tools such as Terraform, you can build virtual networks and use other toolsets for configuration such as Ansible to configure new infrastructure in exact and uniform ways as per the requirements.
Lastly, virtualization has played a vital role in improving disaster recovery. You do not need to restore lost data from a tap to re-provisioned hardware as would have been the case in the past. Instead, you can replicate the entire virtual network infrastructure between sites using different tools that are required for virtualization. These tools may include VMware Site Recovery Manager, which can be automated. Other products, for example, CloudEndure can replicate servers to the cloud, and the entire system is replicated in a staging area that can be activated when a disaster recovery scenario is invoked.
Limitations of Server Virtualization
Above, we have explored the different benefits of server virtualization. But just like every other thing, server virtualization also has its limitations. It is vital for a network administrator to investigate the changing of servers and their architecture so that they can engineer the right solution.
One of the limitations is that if you have servers that are dedicated to applications that have high demands on power for processing, then this may not be the most viable choice. Virtualization works by dividing the processing power of the server among the virtual ones. When the processing power of the server is unable to meet the demand of the application, then the entire system will slow down. Even tasks that typically take a short time for completion begin to take hours. There is also a possibility of the system crashing if the server cannot meet the demands of all the virtual servers within the system. As such, it is vital that the network administrator takes a close look at the use of the CPU before the physical server is divided into several virtual machines.
Additionally, there is a limitation in migration. It is possible to carry out a migration of a virtual server from a physical device to the next if, together, the equipment makes use of a unified constructor’s design. When a system customs a single server, that, for instance, goes on an AMD workstation, and an added one customs an Intel processor, it will be intolerable to carry out porting in a virtual server from a physical machine to the next. You may wonder why an administrator would require the migration of a virtual server from a physical machine. The physical server may require maintenance and porting the simulated ones to supplementary equipment can help in reducing the downtime of the app. Relocation is, hence, important because when migration ceases to be a preference, the requests that run on the computer-generated server will be unavailable until maintenance is done.
The downsides of virtualization are not as many as the benefits, and with the right considerations in place, a network administrator can identify the type that will work efficiently for the enterprise. The benefits are the reason that many companies are still investing in the virtualization of servers. Technology keeps advancing, and as this happens, the need for big data centers continues to decrease as well. The power consumption of servers may also be on the way, and this makes the concept of virtualization not only attractive financially but also a green alternative that can help in the reduction of the carbon blueprint of many companies. As networks use servers, there will be the development of more efficient yet larger computer networks. In fact, virtual servers can top an upheaval in the computing trade over time.
Determining if Server Virtualization Is Necessary for Your Business
If you are wondering if server virtualization is what may be best for your company and you need a few pointers to help you start, then the following section may be useful to you.
Server virtualization brings together multiple operating systems on one server. You can consider it if you need any of the things described below:
If you need to use more operating systems and applications without necessarily breaking the budget for electricity, space, and hardware, then virtualization may be the best option for you. This is because the approach can be instrumental in reducing all these while not affecting the enterprise’s budget in the long-term.
Also, if you wish to reduce the work hours for your IT staff so that they do not have to spend a lot of time on patching, installation, administration, and supporting application servers, then this may be the right time for you as it is an approach that consolidates many of these aspects, making work easier.
If you wish or need to simplify backup and reduce the downtimes of applications, by adding storage space, then virtualization is the best option for you and should ultimately be considered.
Sometimes, you may need to expand your technical skills in the field of networking. Server virtualization may help you to learn the ins and outs of converging network operations and systems. In such cases, virtualization would be the right step to take.
Virtualization may also be the best option for you if you feel that you need to master cloud challenges. With experience in handling cloud challenges, you will be better placed when your business will be migrating to virtualization. This is especially critical when you will eventually have to migrate services that are critical to your business to the cloud.
Just like with other technologies, virtualization involves more than just the purchase and installation of a product. There are four important steps that can be considered part of the virtualization process:
Evaluation of the network’s and system’s current capacity and performance and the requirements it may need in the future
When you consider the above, you may find that you are long overdue for a refresh at your enterprise. You know that it is time for a haul in your systems when you experience server sprawl, and you struggle to achieve stellar performance with old hardware. When looking at the systems, consider the capacity and speeds of the central processing unit, a disk I/ O, and processors. You can also have a look at emails, servers, setup of the hard disk, database applications, and file servers when evaluating where virtualization could lead to improvement. At network levels, you should assess the performance of routing, switching, and even WAN links. Acceleration of the wide-area network, for example, can make such a big difference in performance.
Calculation of the expected payoff if the system or network is virtualized
Look at your enterprise or business and tries to establish what you will gain from embracing virtualization. Consider the enterprise’s short and long-term goals and establish how they fit in with the possibility of virtualization. Consider when you should do it and make further evaluations so that you do not find yourself on the losing end when it comes to virtualization. Look at what you can use in your new endeavor and establish if indeed, it is the right choice for you.
Creation of a strong infrastructure
You can choose a virtualization technology at this point, but you have to ensure that this will be a technology that will work to improve performance while simultaneously reducing costs and complexity at the moment and in the future, too. You could look for a management interface that provides a single interface for the management of the infrastructure and ensures performance and reduction in costs. Consider what switches you will use, hypervisors, storage, and servers.
Map your timeline for virtualization
By the time you will be reaching this stage, you will have all the software and hardware that will be needed for virtualization. The timeline for migration can range from anywhere in a time frame of as little as two weeks, and sometimes, it can go for as long as three months. The time frame will depend on the number of servers and sites and the staff.
From the start, align the network staff and the servers of the company so that you do not end up with high operating costs. The person who deals with the systems will need expertise and skills in managing operating systems, applications, switching, traffic, and VLAN. The network person should understand how to do things such as pushing the quality of service in servers. This is really important because the performance of your network may depend on these people. If it is impossible to have people who can manage these tasks, then you will have to bring in expertise from the outside. With the right tools and virtualization expertise, you can plan and take the virtualization journey that will best fit your organization.
The Potential in Server Virtualization and the Trend It Is Likely to Take
After all, is said and done, you may be wondering why it is important to learn about server virtualization. Below, I explain why it is important to learn about server virtualization if you have even the slightest interest in networking.
Virtualization of servers is a simple concept that has had a profound and even almost profound impact on data centers in many enterprises. It had its roots in the early 60s and was popularized by VMware. The virtualization software was later introduced in the early 2000s for the x86 servers. Since the inception of these servers, many other vendors have begun to develop their own platforms for server-virtualization, and there have been advancements in management, automation, and orchestration. These tools make it easy to deploy, move, and manage virtual machine networks with ease. Before virtualization, many enterprises had to deal with server sprawl, high energy bills, and underutilized computer power, all to be dealt with using manual processes and with inefficiency and inflexibility in the data centers. Today, this has changed, and instead, it has become difficult to find enterprises that do not run their workloads in virtual machine environments.
However, every good thing usually meets yet another good thing that will knock it off its pedestal. The next big thing when it comes to virtualization is going small. The next way that this will transform is that developers will slice applications into microservices that are not only small but also run in containers. There shall also be experimentation with function as a service, otherwise known as serverless computing.
Understanding Containers and Virtual Machines
Docker is a popular tool used for spinning containers. Kubernetes is an innovation of Google. These two are the major enablers for containerization as they help in the management of multiple containers. Containers can be thought of as execution environments that share the host operating system’s kernel.
They are self-contained, streamlined, and even more lightweight compared to virtual machines as they bypass any startup overhead and redundant guest operating systems. Developers are, therefore, able to run as many as approximately 6 to 8 more times containers as virtual machines on one hardware.
So far, containers seem to be a good thing. However, they also have a downside. The use of containers is a relatively new approach, and therefore, there is not a wealth of management tools that are associated with older technologies. There is, therefore, still a lot of work-related to set-up and maintenance that is yet to be done. Additionally, as a new technology, there are also concerns about the security of the containers.
Where virtual machines are concerned, it is relatively easy to move workloads from one host to another. However, bare-metal machines complicate such a movement because they make it hard to move or upgrade. This difficulty comes about because rolling back a machine on a machine state with bare metal servers can be challenging.
Serverless Computing and Virtual Machines
In the traditional cloud movement, there is the provisioning of virtual machines, databases, storage, and every other associated management and security tools. After this, applications are loaded on to the virtual machine.
Serverless computing, on the other hand, is different. In this case, the developers will write the code, and the other aspects are handled by cloud service providers. Developers do not have to contemplate operating systems, servers, managing, and provisioning. Even the physical server that runs the code is the responsibility of the cloud service provider. The code is broken down into specific functions instead of having a monolithic application. When an event occurs and triggers a function, the serverless service runs the function. Customers are charged by function as specified by serverless providers. With the container and microservices, serverless computing usually bypasses virtual machine layers, and the functions run on bare metal. Serverless computing is currently immature, and the cases where they are used are limited.
The use of containers is increasing, and serverless computing as a concept is also growing. Server virtualization is a solid technology that will continue to power many applications in the enterprise environment. The saturation of virtual machines in the enterprise world is estimated to be as high as 90 %.
It is currently hard to think that enterprises can move their critical applications that run smoothly to either serverless platforms or containers. More likely is the probability of having heterogeneous environments in which the use of virtual machines will still be common. Containers still need to run on the same operating system and cannot be mixed between Windows and Linux.
There are new applications that rebuilt with the latest agile methodologies and DevOps because developers now have an easier time with all the options available. They will be able to make case-by-case decisions on whether they should run a new workload in either a container, virtual machine, or serverless environment.
