Module 8 Reading

Bare-Metal Virtualization Uses

1. Consolidate servers: this is probably the original reason for using bare-metal virtualization. a. Retire old or unreliable hardware b. Make optimal use of multicore, high-performance servers c. Maintain application seperation d. Reclaim rack or floor space e. Reduce cooling and power requirements 2. Test installations and upgrades 3. Test a preconfigured application 4. Test what-if scenarios 5. Live migration 6. Dynamic provisioning

Cloud Computing

A networking model in which data, applications, and processing power are managed by servers on the Internet; users of these resources pay for what they use rather than for the equipment and software needed to provide resources. It's like only paying for cell phone minutes you use instead of paying for the towers and switching equipment needed to make your phone work. The word *cloud* is used to obscure the details of equipment and software that actually provide resources. For the most part, customers don't care whether the equipment consists of Windows or Linux servers, large tower computers, or rack-mounted computers, as long as it works

Dynamic Provisioning (Bare-Metal Uses)

Advanced VM management systems can deploy VM's and storage dynamically to meet application requirements. This advanced feature has uses in clustered computing and cloud computing.

VMware Fusion

Another product from VMware, this software runs on macOS and supports the same guest OS's as VMware Workstation

Testing a Preconfigured Application (Bare-Metal Uses)

Are you unsure whether the application the vendor wants to sell you is right for your company? Some vendors offer virtual appliances you can use to evaluate the application without having to install it.

Testing Installations and Upgrades (Bare-Metal Uses)

Before you install a major software package or upgrade on your server, create a copy of the VM (referred to as cloning in some products), and go through a test run to iron out any potential problems or conflicts. If something goes wrong on the production VM, you can revert to a snapshot.

Reclaiming Rack or Floor Space (Consolidation)

By consolidating a dozen physical servers into three or four host servers, you're no longer tripping over a plethora of towers or wondering whether your rack can handle one more server.

Reducing Cooling and Power Requirements (Consolidation)

By reducing the number of server (even with higher-performance machines), you usually save money on the costs of cooling and powering a datacenter, especially when you reduce hundreds of server down to dozens of virtualization servers.

Retiring Old or Unreliable Hardware (Consolidation)

Converting physical machines to VM's and running them on the latest hardware means you can get rid of old hardware, thereby gaining a reliability advantage and avoiding the tedious task of reinstalling and re-configuring a server OS on new hardware. You might also improve performance.

Application Isolation (Virtualization Uses)

Not all software plays well together, so if an application conflicts with other installed software, it can be installed in its own VM, effectively isolating it from the host machine's installed software.

VirtualBox

Originally developed by Innotek, VirtualBox is now developed by Oracle Corporation. Two versions are available: a propriety version that's free for home users and can be purchased for enterprise use, and free open-source version with a reduced feature set. VirtualBox runs on Linux, macOS, or Windows hosts. The propriety version has features similar to VMware Workstation.

Software Development (Virtualization Uses)

Software developers often need to design software that works on multiple OS's and OS versions. Testing on VM's makes this process easier than using a physical computer for each OS to be tested.

Maintaining Application Separation (Consolidation)

Some applications and services run best when they're the only major application installed on an OS. You avoid OS resource conflicts and gain stability and reliability.

Virtual Disk

consists of files on the host computer that represent a virtual machine's hard drive.

Bare-Metal Virtualization Products

1. Microsoft Hyper-V 2. Citrix Hypervisor 3. VMware vSphere All these products have extensive management tools for managing up to hundreds of hosts and a wide array of storage resources. These tools are available for a fee from virtualization software vendors. For example, Microsoft offers System Center Virtual Machine Manager (SCVMM) for managing Hyper-V and ESXi Server hosts. Citrix Hypervisor offers versions with different levels of management, depending on which product you purchase, and VMware sells vCloud Suite to manage an infrastructure as a service (IaaS) cloud computing environment. All these products are designed to provide a secure, reliable, and highly available virtualization infrastructure. The basic tasks of creating and accessing VMs in type 1 hypervisor environments are similar to the process for type 2 hypervisors: A wizard walks you through the process, or you can use scripting tools to batch-create VMs. The real differences lie in host and resource management and the capability to give IT managers the tools needed to virtualize a datacenter, not just one or two servers. This section serves as an introduction to available products so that you have a starting point for doing your own research in the expanding field of virtualization.

Common Virtualization Uses

1. OS TRAINING 2. SOFTWARE TRAINING 3. APPLICATION ISOLATION 4. SOFTWARE DEVELOPMENT 5. WHAT-IF SCENARIOS 6. USE OF LEGACY APPLICATIONS 7. PHYSICAL-TO-VIRTUAL CONVERSION

Private vs Public Cloud

1. Public Cloud: computing resources and their management are the responsibility of the cloud service provider. This arrangement allows a company to focus on its primary business rather than a large IT infrastructure. However, because the cloud resources are in someone else's hands, you must depend on the provider to ensure reliability and security of the provided service and your data. In addition, you are depending on Internet providers to connect your location with the cloud service provider. 2. Private Cloud: VDI, cloud storage, and SaaS are commonly accessed as private cloud services deployed from the company's own datacenter. This setup gives a company more control and more security, yet provides its employees many of the benefits of cloud computing. Drawback is up-front and ongoing costs of maintaining a large IT infrastructure.

Benefits of Cloud Computing

1. Reduced Physical Plant Costs: having fewer servers means less space is needed to house them, and less electricity and cooling are required to keep servers running. 2. Reduced Upfront Costs: paying only for services and software that are used means a company can avoid the startup costs of purchasing a lot of expensive hardware and software. 3. Reduced Personnel Costs: having fewer servers and applications to support means fewer IT employees are needed to support hardware and applications.

Cloud Computing Categories

1. Software as a service 2. Platform as a service 3. Infrastructure as a service The phrase as a service simply means that the resource resides on another server or network than the one using the resource, and customers use it as a paid service. You might also hear the term SPI model, which is based on the combination of the three aforementioned "as a service" terms (Software, Platform, Infrastructure).

Types of Hypervisors

1. TYPE 1 HYPERVISOR: implements OS virtualization by running directly on the host computer's hardware and controls and monitors guests OS's. It also controls access to the host's hardware and provides device drivers for guest OS's. Also called BARE-METAL virtualization, it's used mainly for server virtualization and virtual desktop infrastructures in datacenters. 2. TYPE 2 HYPERVISOR: implements OS virtualization by being installed in a general-purpose host OS, such as Windows 10 or Linux, and the host OS accesses host hardware on behalf of the guest OS. Also called HOSTED virtualization, it's used mostly for desktop virtualization solutions.

Best Known Virtualization Products

1. VMware Workstation Pro 2. VMware Workstation Player 3. VMware Fusion 4. Parallels Desktop for Mac 5. VirtualBox

Use of Legacy Applications (Virtualization Uses)

If you have a favorite application that won't run on a newer OS, you don't have to forego the latest software technology because of one application. You can install the old OS in a VM and run your legacy application on it.

What-If Scenarios (Virtualization Uses)

If you want to try out a software package or see whether a configuration option you read about will actually improve performance, you might not want to risk destabilizing your computer. You can install software and make configuration changes safely on a VM before making the commitment on your production computer. In addition, a snapshot allows you to capture the state of a VM, install software and make other configuration changes, and then revert to the snapshot after you have completed testing.

Physical-to-Virtual Conversion

Let's say your six-year-old machine is getting slow and unreliable, so you bought a new desktop computer. However, you have several applications on your old computer and no longer have the installation media. You can convert your old computer to a virtual machine, and keep all the software and run it on your new desktop computer as a VM. You'll probably even see a speed boost.

Making Optimal Use of Multicore, High-performance Servers (Consolidation)

Some server roles, such as Active Directory, should be the only major network service running on a server. With multicore server CPU's, you're likely to waste a lot of the server's power if you install a single-role OS. Instead, run two, three, or more VM's on the server, making optimal use of the available performance.

Software Training (Virtualization Uses)

Students and employees can be trained on new software packages by giving them VM's with preinstalled software.

Application Virtualization

The virtualization products discussed so far provide whole-system virtualization. All components of the computer hardware are simulated by the hypervisor, and each VM has a full copy of the entire guest OS installed, which runs in its own protected memory space on the host, effectively isolating the VM from the host and other VM's. If the OS on a VM crashes, on that VM is affected. In addition, whole-system virtualization allows you to run an OS in a VM that is totally different from the OS running on the host. This type of virtualization is often used to isolate a single application from the host for testing purposes or when multiple instances of the same application must run on one host, as is often the case with cloud providers. The downside of the whole-system virtualization is that having an entire guest OS in a VM for the purposes of running a single application is resource intensive. Most OS's require a minimum of several GB of RAM and dozens of GB of disk space, plus plenty of CPU time. To mitigate this resource overhead required for whole-system virtualization, many cloud providers and datacenters are turning to APPLICATION VIRTUALIZATION in the form of containers.

Bare-Metal Virtualization

These products (type 1 hypervisors) are targeted mainly for production virtualization in datacenters. These products are installed directly on hardware and have more stringent host machine requirements than hosted products. Because they're targeted for IT departments, they have more features for managing VM's and have a performance advantage over hosted virtualization products. Their installation and use tend to require more sophisticated knowledgeable users. Before learning about specific products, take a look at some applications for bare-metal products.

Citrix Hypervisor (Bare-Metal Product)

This open-source hypervisor uses Linux as a management OS on the host. It's available free or as a commercial edition that adds enterprise-level features, such as fault tolerance, performance management, and host power management. A number of modified Linux versions and solaris can run as the management OS, and like Hyper-V, a Citrix Hypervisor host computer requires a 64-bit CPU with virtualization extensions to run Windows guest OS's. Guest OS support includes most of Windows OS's, starting with Windows XP, and SUSE, Red hat, and CentOS Linux distributions. To manage your host and VM's, Citrix Hypervisor comes with XenCenter. XenCenter provides virtual machine management, monitoring, and administration from any Windows OS.

Parallels Desktop for Mac

This product works on macOS and supports a number of guest OS's including Windows, Linux, macOS, OS/2, and Solaris

VMware Workstation Player

This version of VMware Workstation has a streamlined user interface and few advanced features than Workstation Pro, but it maintains excellent guest OS support. The current version (Workstation 12 Player) is free for personal non-commercial use, but costs about $150 for business or commercial use as of this writing.

VMware Workstation Pro

VMware, the virtualization pioneer in the PC world, released VMware Workstation in 1999. Of the hosted virtualization products, it offers the most features, including multiple snapshots, extensive guest OS support, and nested virtualization (the capability to run a virtual machine inside another virtual machine). VMware Workstation Pro costs about $250 per license as of this writing.

Live Migration (Bare-Metal Uses)

Virtual machines can be migrated to new hardware while they're running for performance or reliability improvements with practically no downtime. Live migration features also ensure VM FAULT TOLERANCE in clustered server environments.

Virtualization software

a software used for creating and managing VM's and creating the virtual environment in which a guest OS is installed.

OS Training (Virtualization Uses)

With virtualization, a computer can have a host OS installed, such as Windows 10, and have virtual machines for numerous Linux distributions, Windows 7, Windows Server 2019, and even Novell Netware. You can also run multiple VM's at the same time by using a virtual network, which enables you to work with both client and server OS's in situations that would normally take two or more physical computers as well as network cabling and switches.

Testing What-If Scenarios (Bare-Metal Uses)

You can create a virtual network and run clones of your production VM's to test ideas for improving your network's performance, functionality, and reliability. This type of testing on live production systems is never a good idea, but it's ideal on virtual machines.

Windows Sandbox

a feature available with Windows 10 Pro and Enterprise (versions 1903 and later) that provides a temporary isolated environment in which to run an application. Although Sandbox is built on containers technology, which is meant for large-scale application with the assurance that it will not interfere with any existing applications or your Windows 10 installation. For example, perhaps you have downloaded a freeware application that you want to try, but you are unsure if it has the features you need and you are concerned about viruses or conflicts with other software on your system. In addition, you know that once you install an application, it can sometimes be difficult to remove all traces of the application when you decide to uninstall it. This is the problem that Windows Sandbox was designed to solve. Sandbox can be installed on a physical machine or a virtual machine. You install it from the Windows Features control panel applet by clicking Windows Sandbox and clicking OK, followed by a computer restart. Once it is installed, you'll find Windows Sandbox on the Start menu. When you start Sandbox, it may take a while to load, but when it does you'll see a window that looks remarkably similar to your Windows desktop. That's because Sandbox is essentially a lightweight VM based on the Windows 10 OS it is running on. Also, while Sandbox looks like a full virtual machine running on Windows 10, it is actually sharing much of the host OS that is loaded into RAM, like containers do. A base Windows Sandbox image only takes about 100 MB of disk space and about 20 MB of RAM with no applications installed. Compare that to a full Windows 10 VM that takes about 20 GB of disk space and at least 1 GB of RAM. Once Sandbox is running, you can copy and paste an application into the Sandbox window and install it. If the application doesn't require installation, you can run it. When you are done working with the application, you can close Sandbox and all traces of the application will be deleted.

Virtual Network

a network configuration created by virtualization software and used by virtual machines for network communication

snapshot

a partial copy of a VM that contains changes made since the VM was created or since the last snapshot was made. It is used to restore the VM to its state when the snapshot was taken. While most virtualization software vendors use the term *snapshot*, Microsoft Hyper-V refers to a snapshot as a CHECKPOINT.

Virtualization

a process that creates a software environment to emulate a computer's hardware and BIOS, allowing multiple OS's to run on the same physical computer at the same time.

Container

a virtualized software environment in which an application can run but is isolated from much of the rest of the operating system and other applications. Containers are still a type of virtualization, but while whole-system virtualization products such as Hyper-V and vSphere virtualize the hardware environment, allowing multiple OS's to coexist on the same host, containers virtualized ONLY PARTS of the operating system. This allows "containerized" applications to have their own copy of critical OS structures like the registry, file system, and network configuration, while sharing the kernel, the host hardware, and possibly some runtime libraries. As with whole-system virtualization, the host OS can constrain the container to limit its host resource usage. For example, a container can be restricted to a certain percentage of the CPU, so even if the containerized application uses 100 percent of the assigned CPU, it's only using 100 percent of the restricted amount. Container virtualization is available in most Linux distributions and starting with Windows Server 2016. Both Linux and Windows Server use a container management platform called Docker.

Software as a Service (SaaS)

also called HOSTED APPLICATIONS or ON-DEMAND APPLICATIONS because the customer doesn't actually buy any software that's installed on their own equipment. Instead, the customer pays for the use of applications that run on a service provider's network. The best-known examples are Google Apps and Microsoft Office 365, which a business or a home user can use to run hosted applications, such as email, calendar, word-processing, and spreadsheet programs. More complex applications involve large database systems, such as payroll services from ADP and customer relationship management software offered by companies such as Salesforce.com. SaaS is usually offered as a subscription based on the number of people using the application. It takes the burden of installation and maintenance off the customer so that companies can focus on maintaining their LANs and Internet access instead of maintaining hundreds of copies of an installed application. In addition, customers can take advantage of new software editions much faster than with the standard deployment times of traditional application upgrades. Some application upgrades require client computer or OS upgrades, but with SaaS, the vendor handles infrastructure upgrades when needed. In addition, SaaS is available anywhere the customer has a connection to the Internet. Mobile users and telecommuters have access to the same applications they use in the office without having to install the software on their laptops or home computers. Some applications can't even be installed on home computers, but with SaaS, the software runs on remote servers, so local installations aren't necessary.

Platform as a Service (PaaS)

also called HOSTED PLATFORM-- is similar to SaaS, but the customer develops applications with the service provider's tools and infrastructure. After applications are developed, they can be delivered to the customer's users from the provider's servers. This setup differs from SaaS, in which the service provider owns the applications delivered to useres; with PaaS, the customer develops and owns the application and then delivers it to a third party. Developers who use PaaS can take advantage of many of the same benefits enjoyed by SaaS users. In addition, after an application is developed with PaaS, the developer can usually deploy the application immediately to customers who access it as a hosted application. The same operating environment used to develop the application is used to run it, which bypasses the sometimes complex and problem-prone process of migrating from a traditional development environment to a production environment. The most common PaaS products are Salesforce.com's Apex, Azure for Windows, Google's App Engine for Python and Java, WaveMaker for Ajax, and Engine Yard for Ruby on Rails. Others are available, but details on these development platforms are beyond the scope of this book. PaaS is still an evolving model for application development, and platforms will come and go as developers weed out what works and what doesn't. Developing in the cloud is likely here to stay because it offers benefits that aren't usually available in a locally managed environment. In addition, because small businesses and individual developers have access to expensive, full-featured development environments, entrepreneurs can be on an equal footing with the big boys, which increases competition and innovation—and that's always a good thing.

Infrastructure as a Service (IaaS)

or HOSTED INFRASTRUCTURE, allows companies to use a vendor's storage or even entire virtual servers as needed. Traditionally, if a company needs another 100 GB of storage to house a new database, it has to buy a new hard drive-- assuming the server can accommodate a new hard drive. By using IaaS, the company simply pays for another 100 GB of space without worrying about how that space is actually provided. In addition, if a customer needs another server to handle its application workload, it simply pays for the amount of processing and storage the additional server actually requires instead of paying for the physical device. In most cases, IaaS servers run as virtual machines on more powerful physical servers. IaaS differs from other hosted services because customers mostly rent the resources they're using but are still responsible for application installations and upgrades. Although IT staff can be reduced because the IaaS vendor handles physical device upkeep, customers still need IT staff to configure and manage applications and server OSs. IaaS isn't just for server infrastructure. Companies can "upgrade" to the latest OSs and desktop applications by using virtualized desktops through their IaaS providers. By accessing desktops remotely, IaaS customers can use thin clients (client computers with minimal hardware resources) or computers with older OSs to make use of the latest desktop OSs and applications. This IaaS feature, virtual desktop infrastructure (VDI), is becoming a popular way for companies to deliver desktop OSs and applications rather than use traditional methods of installing OSs and applications locally.

guest OS

the operating system installed in a VM.

Hypervisor

the part of virtualization software that creates and monitors the virtual hardware environment that allows multiple VM's to share physical hardware resources.

Virtual Machine (VM)

the virtual environment that emulates a physical computer's hardware and BIOS.

VMware vSphere (Bare-Metal Product)

vSphere includes VMware ESXi Server, a hypervisor that is installed directly on the physical server without a management OS. After ESXi Server is installed, a basic command-console based on Linux is available for simple configuration tasks, such as IP address configuration. Most configuration tasks are performed from a remote client OS using the Web browser-based vSphere Client. ESXi SErver has the broadest guest OS support of the type 1 hypervisors, including Windows versions back to Windows 3.1, more than a dozen Linux distributions, Novell NetWare, and Solaris.

Microsoft Hyper-V (Bare-Metal Product)

was introduced with Windows Server 2008 and can be isntalled as a server role, in which case the hypervisor is installed as a layer of software between Windows Server and the server hardware. Windows Server acts as a parent or management OS for VM's installed with Hyper-V. Hyper-V is included with Windows Server at no additional cost, or you can download the stand-alone Hyper-V Server free from the Microsoft Web site. Hyper-V supports advanced features, such as host server clustering and live migration, and requires a 64-bit CPU with virtualization extensions enabled on the host system. Virtualization extensions offload some virtualization work to the CPU and are present on most current CPU's. A big advantage of using Hyper-V is that Microsoft provides virtual instances of the OS with no additional licensing fees.