Virtualization Tutorial

What is virtualization?

• Virtualization is an abstraction layer that breaks the hard connection between the physical hardware and the operating system.

• A virtual infrastructure is an enterprise-wide solution that provides fluid, powerful computing that maximizes resource utilization and cost savings.

• Virtual machines are the key element to a virtual infrastructure.

• Virtualization allows you to run multiple virtual machines with heterogeneous operating systems and applications to run in isolation, side-by-side on the same physical machine.Using virtualization, you can dynamically move resources where they are needed, and move processing where it makes most sense. This is possible because VMware detaches the operating system and its applications from the hardware they run on.

Physical vs. virtual

• A virtual machine is a software computer that, like a physical computer, runs an operating system and applications. It has its own set of virtual hardware on which a guest operating system and its applications run. The operating system sees a consistent set of hardware regardless of the actual physical hardware components

• Virtual machines are not emulators or simulators. They are real machines that can do the same things physical computers can do and more. Because of the flexibility of virtual machines, physical computers become less a way to provide services (applications, databases, and so on) and more a way to house the virtual machines that provide those services.

• Note:
  In computing, an emulator is hardware or software that enables one computer system (called the host) to behave like another computer system (called the guest). An emulator typically enables the host system to run software or use peripheral devices designed for the guest system.

Benefits of virtual machines

• A physical machine is hard to move, difficult to copy, and bound to a specific set of hardware. Virtual machines are easy to copy and move because they are independent of physical hardware.

• Also, they are easy to manage because they are isolated from other virtual machines running on the same physical hardware and insulated from physical-hardware change

• Virtual machines enhance infrastructure by providing:
  • Freedom from physical hardware constraints V
    • Virtual machines allow the operation of heterogeneous operating systems running across heterogeneous hardware.
  • Backup and recovery with little or no down-time
    • You can configure virtual machines with operating systems and applications once and then clone them many times. Backing up a virtual machine is as easy as backing up a few files. In this way, virtual machines ensure fast deployment and reliability.
  • Greater resource utilization
    • Multiple virtual machines can run on the same physical server. In addition, consolidating computing power to fewer physical computers can substantially increase power savings in your enterprise.

• Note:
  Software deployment is all of the activities that make a software system available for use. The general deployment process consists of several interrelated activities with possible transitions between them. These activities can occur at the producer side or at the consumer side or both.

How does vSphere work?

• VMware vSphere is a system for managing your virtual infrastructure.
• VMware vCenter Server is a tool that manages multiple host servers that run multiple virtual machines.
  • With vCenter Server, you can quickly provision new server virtual machines and create a library of standardized virtual machine templates so your newly provisioned systems always conform to your datacenter requirements.
  • The vCenter Server lets you migrate running virtual machines between host servers so that you can perform hardware maintenance with minimal downtime.
  • Other vCenter Server features allow you to balance virtual machine workloads across hosts and manage virtual machines for high availability and disaster recovery.
• Note:
  In general, provisioning means “providing” or making something available. The term is used in a variety of contexts in IT. For example, in grid computing, to provision is to activate a grid component, such as a server, array, or switch, so that it is available for use. In a storage area network (SAN), storage provisioning is the process of assigning storage to optimize performance. In telecommunications terminology, provisioning means providing a product or service, such as wiring or bandwidth.

What is vCenter Server?

• VMware vCenter Server provides a convenient single point of control to the datacenter. It runs on top of a Windows server to centrally manage your VMware ESX/ESXi hosts and provide essential datacenter services such as access control, performance monitoring, and configuration.

• vCenter Server unifies resources from individual hosts to be shared among virtual machines in the entire datacenter. It accomplishes this by managing the assignment of virtual machines to the hosts and the assignment of resources to the virtual machines within a given host based on the policies that the system administrator sets

• vCenter Server allows the use of advanced vSphere features such as vSphere DRS, vSphere HA, and vMotion.

What is the vSphere Client?

• The vSphere Client is the primary interface for creating, managing, and monitoring virtual machines, their resources, and their hosts. It also provides console access to virtual machines.

• The vSphere Client is installed on a Windows machine with network access to your vCenter Server or your ESX/ESXi host. The interface displays different options depending on which type of server you are connected to.

• Although vCenter Server performs all vSphere activities, you use the vSphere Clientto monitor, manage, and control vCenter Server. A single vCenter Server or ESX/ESXi host can support multiple, simultaneously connected vSphere Clients.

Networking in vSphere

VMware vSphere provides two types of network architecture. Networking with vSphere Distributed Switches manages virtual machine and host networking at the datacenter level, while networking with Standard Switches manages virtual machine and host networking at the host level

What is vSphere Distributed Switch architecture?

• Networking with vSphere Distributed Switches is driven from the datacenter level.
• A vSphere Distributed Switch exists as an object on the datacenter that acts as a virtual switch across all associated hosts, enabling virtual machines to keep consistent network configuration as they migrate across hosts.
• Uplinks connect the vSphere Distributed Switch to physical network adapters on associated hosts.
  • Each host can connect one physical network adapter to a vSphere Distributed Switch for each uplink port on the vSphere Distributed Switch.
  • Virtual machine NICs connect to vSphere Distributed Switches through Distributed Port Groups, which aggregate multiple ports under a common configuration and provide a stable anchor point for virtual machines connecting to a labeled network.

What is vSphere Standard Switch architecture?

• Networking with vSphere Standard Switches is driven from the host level.
• A vSphere Standard Switch works much like a physical switch, detecting which virtual machines are connected to each of its virtual ports and using that information to forward traffic to the correct virtual machines.
• One or more port groups connect to a Standard Switch and specify port configuration options such as bandwidth and VLAN tagging policies for each member port. Each virtual machine NIC can be assigned to one port group.

Storage in vSphere

• Every virtual machine uses a virtual hard disk to store its operating system, program files, and other data associated with its activities.
  • A virtual disk is a large physical file, or a set of files, that can be copied, moved, archived, and backed up as easily as any other file.
    • Virtual disk files are stored on dedicated storage space on a variety of physical storage systems, including internal and external devices of a host, or networked storage, dedicated to the specific tasks of storing and protecting data.
• A host can discoverstorage devices to which it has access and format them as datastores.
  • The datastore is a special logical container, analogous to a file system on a logical volume, where hosts place virtual disk files and other files that encapsulate essential components of a virtual machine.
  • Datastores can hide specifics of different storage products and provide a uniform model for storing virtual machine files

What are the inventory views?

• Inventory views provide views of all the objects that the vCenter Server manages, such as datacenters, resource pools, clusters, networks, datastores, datastore clusters, templates, hosts, and virtual machines.

• The four inventory views are:
  • Hosts and Clusters
    • Displays the inventory hierarchy of all inventory objects except templates, networks, and datastores.
  • Virtual Machines and Templates
    • Displays the list of virtual machines and templates.
  • Networks
    • Displays the list of networks.
  • Datastores and Datastore Clusters
    • Displays the list of datastores and datastore clusters.

• To change the inventory view, choose View > Inventory or select an inventory view from the vSphere Client Home page

What is Consolidation?

• Consolidation of computing resources is a response to server sprawl, a situation that occurs when under-utilized servers take up more physical space and consume more resources than the workload justifies. Using consolidation, you can convert your physical computers into virtual machines, which can provide cost savings and more flexibility in your IT environment

• Note:
  Server sprawl is a term used in the information technology industry.It describes a set of situations that can occur in data centers that result in poor hardware resource utilization, poor system and software level security, and wasted energy. Various techniques exist to mitigate server sprawl, such as computer virtualization.

Explore the inventory

• The inventory is a hierarchy of objects that allow you to manage your virtual enterprise.
• These objects are either containers of other objects, such as folders and datacenters, or objects that you manage, such as hosts and virtual machines.
• The inventory shows you all objects and object relationships and allows you to organize these objects and access the vCenter operations that manage them.
• You can view the inventory in the left panel of the vSphere Client when you are connected to vCenter Server.

What is a datacenter?

• A datacenter is the primary container of inventory objects such as hosts and virtual machines.
  • From the datacenter, you can add and organize inventory objects. Typically, you add hosts, folders, and clusters to a datacenter.

• The vCenter Server can contain multiple datacenters. Large companies might use multiple datacenters to represent organizational units in their enterprise.

• Inventory objects can interact within datacenters, but interaction across datacenters is limited. For example, you can move a virtual machine with vMotion technology across hosts within a datacenter but not to a host in another datacente

What is a host?

• A host is a computer that uses virtualization software to run virtual machines.
  • Typically, a host is a computer running ESX or ESXi software.
• Hosts provide the CPU and memory resources that the virtual machines use and give the virtual machines access to storage and networks.
  • Multiple virtual machines can operate on the same host at the same time.
• Adding a host to the vCenter Server allows you to manage it and the virtual machines that run on it.

What is a virtual machine?

• A virtual machine is a software computer that, like a physical computer, runs an operating system and applications.
  • An operating system installed on a virtual machine is called a guest operating system.
• Every virtual machine has virtual devices that provide the same functionality as physical hardware. Virtual machines get CPU and memory, video cards, access to storage, and network connectivity from the hosts they run on.
• In vSphere, virtual machines run on hosts or clusters. Multiple virtual machines can run on the same host or cluster at the same time

What is virtual hardware?

• Just as a physical computer has hardware devices such as CPU and memory, a virtual machine has virtual hardware devices. - If you look at a virtual machine’s configuration, you find virtual CPU, memory, hard disks, CD/DVD drives, floppy drives, Ethernet adapters, sound cards, and so on. Each virtual device performs the same function for the virtual machine as does the hardware on a physical computer.
• Virtual hardware lets the virtual machine divide up the physical hardware as needed. For example, you can run many virtual machines on a single physical CPU, each appearing to have its own virtual CPU. You can move a virtual machine from one host to another and the mappings between the virtual and physical devices change automatically, while the virtual devices remain unchanged. Through virtual hardware, virtual machines are insulated from the details of physical hardware.
• For a complete list of virtual devices, see the vSphere Client online help

What is a template?

• A template is a master image of a virtual machine that you can use to create and provision new virtual machines.
  • This image typically includes an operating system, applications, and a virtual machine configuration that defines a full set of virtual hardware.
• You can create a template by converting an existing virtual machine to a template, cloning a virtual machine to a template, or cloning an existing template. You can then create new virtual machines by deploying the template.
• Using templates can save the time of configuring a new virtual machine and installing a guest operating system.
• Templates appear only in the Virtual Machines and Templates inventory view

What is a folder?

• A folder is a container used to further refine object grouping within your inventory. Folders provide a natural structure on which to apply permissions.
• For example, using folders, you can organize virtual machines and templates based on function. Similarly, you can use folders to group datacenters by geographic location.
• You can group the following inventory objects in folders:
  • Datacenters
  • Virtual machines (which include templates)
  • Computer resources (which include hosts and clusters)
• The objects grouped within a folder must be of the same type.

What is a cluster?

• A cluster is a group of hosts that share resources and a management interface.
• When you add a host to a cluster, the host’s resources become part of the cluster’s resources. The cluster manages the resources of all hosts within it.
• Clusters enable the vSphere Distributed Resource Scheduler (DRS) and vSphere High Availability (HA) solutions
  • vSphere DRS continuously balances virtual machine workloads across your ESX/ESXi hosts.
  • vSphere HA allows the virtual machines running on ESX/ESXi hosts to automatically recover from host failures.

What is a resource pool?

• A resource pool provides a way to divide the resources of a stand-alone host or a cluster into smaller pools. A resource pool is configured with a set of CPU and memory resources that the virtual machines that run in the resource pool share.
• Resource pools are self-contained and isolated from other resource pools.
• You can combine multiple physical servers into a single resource pool that aggregates CPU and memory capacity.
• Virtual machines execute in, and draw their resources from, resource pools. This arrangement allows virtual machine workloads to continuously balance across resource pools. When the workload increases, the vCenter Server automatically allocates additional resources and transparently migrates virtual machines between hosts in the resource pool

What is a datastore?

• A datastore is a logical container that holds virtual machine files and other files necessary for virtual machine operations.

• Datastores can exist on different types of physical storage, including local storage, iSCSI, Fibre Channel SAN, or NFS. A datastore can be VMFS-based or NFS-based.

• Note:
  A storage area network (SAN) is a dedicated network that provides access to consolidated, block level data storage. SANs are primarily used to enhance storage devices, such as disk arrays, tape libraries, and optical jukeboxes, accessible to servers so that the devices appear like locally attached devices to the operating system. A SAN typically has its own network of storage devices that are generally not accessible through the local area network (LAN) by other devices. The cost and complexity of SANs dropped in the early 2000s to levels allowing wider adoption across both enterprise and small to medium sized business environments.
  • A SAN does not provide file abstraction, only block-level operations. However, file systems built on top of SANs do provide file-level access, and are known as SAN filesystems or shared disk file systems.

What is a datastore cluster?

• A datastore cluster is a collection of datastores that share resources and a management interface. When you add a datastore to a datastore cluster, the cluster’s resources become part of the datastore cluster’s resources.
• You use datastore clusters to aggregate storage resources, which enables you to support resource allocation policies at the datastore cluster level.
• When you create a datastore cluster, you can use Storage DRS to manage storage resources. The I/O load balancing functionality available with Storage DRS is available only when all hosts connected to the datastores in the datastore cluster are running vSphere version 5 or later.

Using vSphere

• vSphere is a software solution for deploying and managing virtual machines across a datacenter.
• With vSphere, datacenters can instantly provision servers, globally manage resources, and eliminate scheduled downtime for hardware maintenance.

Creating a datacenter

• Create a datacenter as a container for hosts, virtual machines, resource pools, and clusters.
• Datacenters are always created under the root folder in the Hosts and Clusters inventory of a single vCenter Server, in a folder under the root folder, or under a vCenter object in a Linked Mode inventory.
• To create a datacenter, select the root folder in the inventory and choose File > New > Datacenter. You can create datacenters only when you are logged in to the vCenter Server. Datacenters are not available when you are connected directly to a host.
• Creating a datacenter allows you to add hosts to it.

Adding a host

• A host is a computer that uses virtualization software to run virtual machines.
• To add a host to the datacenter, you must have a computer running ESX or ESXi software.
• When you add a host, it will be managed by the vCenter Server.
• After you add the host, use the vSphere Client to manage it and the virtual machines that run on it.
• To add a host, select the datacenter you want to add the host to and choose File > New > Add Host.

Creating a virtual machine

• You can use several methods to create virtual machines to add to your inventory:
  • create a new, blank virtual machine
  • convert a physical computer to a virtual machine
  • deploy from a template
    
  • clone an existing virtual machine
• The vSphere Client provides a simple and flexible user interface from which you can create virtual machines.
• A wizard guides you through the steps to produce a complete and working virtual machine.
• When you create a virtual machine, it’s created on the host you select. The virtual machine runs on that host and uses that host’s resources. You can move virtual machines from one host to another within the same datacenter.

Creating a new virtual machine

• Creating a new virtual machine allows you to customize options such as number of processors, memory, network connections, and storage. You can create new virtual machines on hosts or clusters.
• Before you create a virtual machine, decide which host or cluster the new virtual machine should reside on, the type of guest operating system you will install on the new virtual machine, and the location of the CD or image files for the installation. You also need appropriate vCenter Server permissions to create virtual machines.
• To create a new virtual machine, select the host or cluster in the inventory you want to run the new virtual machine on and choose Inventory > Host > New Virtual Machine or Inventory > Cluster > New Virtual Machine.
• A new virtual machine is like a physical computer with a blank hard disk. After you create the new virtual machine, you need to install a guest operating system on it. You can also change the settings of the virtual machine at any time.

Installing a guest operating system

• A new virtual machine is like a physical computer with a blank hard disk. Before you can use it, you need to install an operating system. An operating system on a virtual machine is called a guest operating system.
• Installing a guest operating system on a virtual machine is essentially the same as installing it on a physical computer. You must have a CD-ROM or ISO image containing the installation files from an operating system vendor. As with physical computers, a separate operating system license is required for each installation.
• After you install a guest operating system, vCenter Server allows you to use the virtual machine, just as you would a physical computer, for tasks such as installing applications or managing power operations.

Customizing the guest operating system

• When you deploy a new virtual machine from a template, or clone an existing virtual machine, you can customize the new guest operating system. You can customize the identity and network settings of your virtual machine’s guest operating system so that it is ready to begin work immediately in your target environment. You can then save your virtual machine settings in a specification that you can recall later and reuse.
• Before you complete the Deploy Virtual Machine or Clone Virtual Machine wizard, you have the option of customizing the guest operating system. If you choose this option, a customization wizard guides you through the configuration options.
• To access saved customization specifications, choose View > Management > Customization Specifications Manager. From here, you can edit existing specifications, or create new ones that are stored for later use.

Cloning a virtual machine

• A clone is an exact copy of a virtual machine. When you create a clone, the vCenter Server lets you customize the guest operating system of that virtual machine. You can run the new clone on any host within the same datacenter as the original virtual machine
• To clone a virtual machine, select the virtual machine and choose Inventory > Virtual Machine > Clone. The Clone Virtual Machine Wizard guides you through the steps needed to clone the virtual machine. You can clone a virtual machine in any power state.
• During this process you need to:
  • Give the virtual machine a name that is unique to other virtual machines and templates within the datacenter.
  • Choose the host or cluster on which the new virtual machine will run.
  • Assign a datastore for the virtual machine files
• During the Clone Virtual Machine Wizard, you can customize the guest operating system of the new virtual machine. Choosing this option launches the Guest Operating System Customization wizard.

Importing a virtual appliance

• A virtual appliance is a prebuilt virtual machine that has an operating system and other software already installed. After a virtual appliance is imported, you have a fully functional virtual machine.
• You can obtain virtual appliances from a variety of sources. VMware Virtual Appliance Marketplace has a large catalog of virtual appliances available for download. VMware or other vendors might also distribute virtual machines on CD or DVD disks.
• You do not need to have a virtual appliance before starting the Import Virtual Appliance wizard. The wizard enables you to browse virtual appliances on the Virtual Appliance Marketplace and install them directly. In addition, you can install virtual appliances from a local hard disk if you have already obtained a virtual appliance, or you can enter the URL of a location on the Internet where a virtual appliance resides.
• To start the wizard, choose File > Virtual Appliance > Import.

Converting a physical machine to a virtual machine

• Use VMware Converter to convert your physical computers to virtual machines. VMware Converter converts Microsoft Windows-based physical computers and third-party image formats to VMware virtual machines.
• VMware Converter copies the data on the hard disk of a physical source computer and transfers that data to a target virtual disk (the new cloned disk). Then the migrated operating system is adjusted so that it can function on virtual hardware. VMware Converter outputs a completely new virtual machine based on the source physical computer. The migration process is nondestructive, so you can continue to use the original source computer.
• VMware Converter is available as a free download from the VMware Web site.

Deploying from a template

• When you deploy a virtual machine from a template, the vCenter Server lets you customize the guest operating system of that virtual machine. You can run the new virtual machine on any host within the same datacenter as the template

• The Deploy Template Wizard guides you through the steps for deploying a template. To start the wizard, right-click the template and choose Deploy Virtual Machine from this Template.
• During this process you need to:
  • Give the virtual machine a name that is unique to other virtual machines and templates within the datacenter.
  • Choose the host or cluster on which the new virtual machine will run.
  • Assign a datastore for the virtual machine files.

• During the Deploy Template Wizard, you can customize the guest operating system of the new virtual machine. Choosing this option launches the Guest Operating System Customization wizard.

Creating templates

• You can create a template with the following methods:
  • Convert a virtual machine into a template
  • Clone a virtual machine into a template
  • Clone an existing template
• When you clone a virtual machine into a template, a new template is created with the same configuration as the virtual machine, and the original virtual machine remains available in the inventory. Likewise, when you clone a template, a copy of the template is created and the original template remains.
• To create a template, select a virtual machine from the inventory and choose Inventory > Virtual Machine > Template > Convert to Template or Inventory > Virtual Machine > Template > Clone to Template. To clone an existing template, select the template and choose Inventory > Template > Clone.
• After you create a template, the vCenter Server adds the template in the Virtual Machines & Templates view.

Using virtual machines

• Virtual machines are the key component in a virtual infrastructure and can be used to enhance performance within your enterprise. Virtual machines allow concurrent operation of multiple, heterogeneous operating systems and applications within an enterprise with consolidated physical hardware and increased reliability. After you install a guest operating system and applications onto a virtual machine, use the vCenter Server to manage its operation. You can change the power state of a virtual machine, edit a virtual machine’s configuration, migrate a virtual machine to another host, and add virtual hardware devices to a virtual machine.

Virtual machine power states

• The power state of a virtual machine indicates whether the virtual machine is active and functional. A virtual machine has several power states, but the three basic states are: On, Off, and Suspend. Extra functions exist in addition to the basic virtual machine power operations, but VMware Tools must first be installed in the virtual machine to use them.
• You can use several access points to change these power states:
• To manually change a power state, select the virtual machine, then choose Inventory > Virtual Machine and choose the power option menu item, or click one of the power option buttons on the main toolbar. To schedule an automatic power state change, use the Scheduled Tasks option in the navigation bar.
• If a power state option is not currently available, it is disabled and it cannot be selected.

Adding virtual hardware

• You might need to add virtual hardware, such as DVD/CD-ROM drives, Ethernet adapters, or an additional hard drive, to your virtual machine after it is created.
• In most cases, the virtual machine must be powered off for you to modify the virtual hardware.
• To add virtual hardware devices, select the virtual machine from the inventory and choose Inventory > Virtual Machine > Edit Settings. In the Virtual Machine Properties dialog box, click the Hardware tab and click Add to start the Add Hardware wizard.
• After you complete the wizard, the new virtual hardware appears in the hardware list displayed in the Virtual Machine Properties dialog box.

Editing virtual machine settings

• The virtual machine Properties dialog box is an editor that you can use to change the hardware configuration of a virtual machine, virtual machine options, and virtual machine resource settings.
• In many cases, the virtual machine must be powered off for you to modify its settings.
• To access a virtual machine’s settings, from the Inventory, select the virtual machine you want to edit and choose Inventory > Virtual Machine > Edit Settings.
• The Virtual Machine Properties dialog box has five tabs: Hardware, Options, Resources, Profiles, and vServices.
  • The Hardware tab enables you to add, remove, and reconfigure virtual hardware devices.
  • The Options tab enables you to modify configuration settings for the virtual machine.
  • The Resources tab enables you to modify the CPU, memory, video card, disk, and network resource allocations for the virtual machine.
  • The Profiles tab enables you to associate a storage policy with a virtual machine to meet the requirements of its applications.
  • The vServices tab enables you to apply a vService dependency that specifies a particular service on which vApps and virtual machines can depend.

Migrating a virtual machine

• You can move virtual machines by using migration —the process of moving a virtual machine from one host to another. Migration options include the following:
  • vSphere vMotion (Live migration)
    • vSphere vMotion moves a running virtual machine from one host to another. If the virtual machine is powered on and uses storage and network options available to the new host, it can be moved without stopping applications or disrupting the guest operating system.
  • Cold migration
    • Cold migration moves a powered off virtual machine from one host to another. Migration can be performed by dragging the virtual machine from one host to another within the same datacenter.
• You can move virtual machines between hosts within the same datacenter, but you cannot move virtual machines across datacenters. You can move virtual machines manually, or you can set up a scheduled task to perform the migration.

Using folders

• You can group the following inventory objects in folders to further refine object grouping within your inventory:
  • Datacenters
  • Virtual machines and templates
  • Hosts and clusters
  • Datastores and datastore clusters Network objects
• The objects grouped within a folder must be of the same type. The types of objects a folder can contain can also vary with the inventory view.
• To create a folder, select the inventory root folder, a datacenter, a host, or a cluster. Then choose File > New > Folder. The folder will be created below the inventory object you selected in the inventory hierarchy.
• To add objects to the folder, drag them onto the folder.
• To delete a folder, select the folder in the inventory and choose Edit > Remove. If you delete a folder, you delete all of the inventory items within it. If the items in the folder are hosts, they are disconnected from the vCenter Server system.

Creating clusters

• When you create a cluster, decide whether to enable the vSphere HA or vSphere DRS solutions on it. You can enable either of these options by using the wizard during cluster creation.
• To create a cluster, select the datacenter to add the cluster to. Then choose File > New > Cluster.
• You add hosts already in the inventory to the cluster by dragging them onto the cluster object. You can add new hosts directly into the cluster by selecting the cluster and choosing Inventory > Cluster > Add Host.

Using clusters

• Use clusters to maximize host utilization and provide high availability for virtual machines
• Clusters distribute resources across hosts and manage load balancing. Using clusters, you can enable the following VMware solutions:
  • vSphere Distributed Resource Scheduler (DRS)
    • vSphere DRS continuously balances virtual machine workloads across your ESX/ESXi hosts. When virtual machine activity requires more CPU or memory resources than the host it is running on can provide, the vCenter Server system triggers vMotion migrations to balance the work load.
    • vSphere High Availability (HA) vSphere HA allows the virtual machines running on ESX/ESXi hosts to automatically recover from host failures. When a host fails, all associated virtual machines are immediately restarted on other hosts in the cluster.
• You can further refine cluster usage by creating resource pools to hierarchically partition available CPU and memory resources of a cluster

Creating resource pools

• When you create a resource pool, you can specify resources, such as CPU and memory shares, for a set of virtual machines. You can specify reservations, limits, and shares that determine how the resources are allocated.
• To create a resource pool, select a host or cluster in the inventory and choose Inventory > Host > New Resource Pool or Inventory > Cluster > New Resource Pool. The New Resource Pool wizard guides you through the creation process.
• After you create a resource pool, you can add virtual machines to it by dragging them onto the resource pool object. Virtual machines added to a resource pool share the CPU and memory resources according to the resource pool’s configuration

Using resource pools

• After you create a resource pool, the vCenter Server manages the shared resources and allocates them to virtual machines within the resource pool. Using resource pools, you can:
  • Allocate processor and memory resources to virtual machines running on the same host or cluster.
  • Establish minimum, maximum, and proportional resource shares for CPU and memory.
  • Modify allocations while virtual machines are running.
  • Enable applications to dynamically acquire more resources to accommodate peak performance.
• Use the vSphere Client to add virtual machines to resource pools, view resource usage, and set resource reservations, limits, and shares.

Consolidating an enterprise

• You can recreate a physical computer as a virtual machine that runs in exactly the same way as the physical computer did. You can select any number of physical computers and convert them into virtual machines to consolidate your enterprise. The consolidation process includes the following steps:
  1. Discover the physical computers in your organization.
  2. Analyze the workload of each discovered computer and identify the computers that are good candidates for virtualization.
  3. Convert the physical computers to virtual machines.
• To start consolidation, click Consolidation on the navigation bar. The consolidation user interface will guide you through the process of analyzing and converting your physical computers into virtual machines