Chapter 8. Pools

Virtual desktops provide the enterprise with the benefits of high availability, scalability and interoperability. To optimize their use and maintenance, virtual machines can be placed in pools. Each desktop in a desktop pool can be used by any user in a particular group on demand, but a single desktop cannot be used concurrently by multiple users. Different desktop pools can be set up for different purposes. For example, there can be one desktop pool for the Marketing department, another for Research and Development, and so on. The user does not always get the same desktop, but gets an available desktop of the required type, from the appropriate pool.
This section describes how to create, maintain and remove pools of desktops. It includes allotting desktops to users, detaching users from desktops and assigning permissions to a virtual pool administrator.

8.1. Creating Desktop Pools

Use the Pools tab to create a set of identically configured desktops. A user associated with a desktop pool can use any available desktop in the pool. Virtual desktop pools must be created within a migration domain, and cannot be migrated outside a cluster.
Once a user logs on to a desktop that belongs to a pool, the desktop belongs to that user alone until it is released according to the pool type. When the user finishes working on a desktop, the desktop image reverts to base image, and becomes available to any user in the pool. Assigning users to a desktop pool is described later in this section.
To create a desktop pool:
  1. Select System from the root of the Tree pane. Click the Pools tab. A list of pools displays.
  2. Click the New button.
  3. The New Pool dialog box displays the following tabs: General, Pool, Console, Host, Resource Allocation and Boot Options. If you choose Windows as the operating system, a Windows Sys Prep tab also displays. Ensure that you enter the mandatory information in the mandatory fields. Unfilled mandatory fields display with a colored border.
  4. In the General group, enter the basic information about the pool, and the type of virtual machines required, as listed in the table.

    Table 8.1. New Pool Dialog Box Fields

    Field
    Description
    Notes
    Data Center
    Select an existing data center from the list.
    The Default data center displays by default.
    Host Cluster
    The name of the host cluster to which the pool is attached. It can be hosted on any physical machine in the cluster depending on the policy rules. This is the migration domain for the virtual machine. The Default cluster displays by default.
    Name
    The name of the new pool. Ensure it is a unique name. The name cannot be any longer than 15 characters, and must contain at least one alphabet, a-z. A number is appended onto the name of the desktop pool to create a unique name for the virtual desktops. For example, if the desktop pool is named HR, and has five virtual desktops, the names of the virtual desktops will be, HR-1, HR-2, HR-3, HR-4, HR-5. Ensure that the name is succinct rather than verbose. The maximum length of a virtual machine name is 15 characters. Follow the operating system's rules for virtual machine names.
    Description
    A meaningful description of the new pool.  
    Number of VMs
    Enter the Number of VMs (Virtual Machines) to create for the pool.
    Based on Template
    Select an existing template to create the virtual machines from an existing model. See Section 6.2.1, “Creating Virtual Machines from Existing Templates”
    The field displays the list of existing templates in the storage domain.
    Memory Size (MB)
    The amount of memory assigned to each virtual machine. Consider the processing and storage needs of the applications that are intended to run on the virtual machines. The maximum allowable memory for a virtual machine is 256GB, allowing even the most memory-intensive enterprise workloads to be virtualized.
    Total Cores
    The processing power allocated to the virtual machine, as CPU Cores, from 1 to 16 on the slider bar. It is recommended that you do not assign a number that is too high, or more cores than actually exist on the physical host.
    CPU Sockets
    The number of CPU sockets for the virtual machine from 1 to 16 on the slider bar. It is recommended that you do not assign a number that is too high, or more CPUs than actually exist on the physical host.
    Operating System
    The operating system. Valid values include a range of Windows and Linux variants. This is a display only field, as no operating system is actually installed during this process.

  5. In Pool, select one of the following pool types: Manual or Automatic.

    Table 8.2. Pool Types Fields

    Field
    Description
    Notes
    Manual The administrator is responsible for explicitly returning the desktop to the pool. The desktop reverts to the original base image after the administrator returns it to the pool.
    Automatic When the desktop is shut down, it reverts to its base image and is then returned to the desktop pool.

  6. If the Operating System chosen was Windows, the Windows Sys Prep group displays.
    New Pool Windows Sys Prep

    Figure 8.1. New Pool Windows Sys Prep


    Enter the following information:

    Table 8.3. Windows Sys Prep Fields

    Field
    Description
    Notes
    Domain Enter the domain in which the virtual machines are to be created.  
    Time Zone Enter the time zone in which the virtual machines are to run. This is the time zone for the virtual machines, and not necessarily the time zone for the physical host on which the virtual machines are to run.

  7. Enter information in the Console group, to specify the communication protocol to be used, whether USB devices are allowed, and the number of monitors that the virtual machines are permitted.

    Table 8.4. New Virtual Machine Dialog Box Fields

    Field
    Description
    Notes
    Protocol Define the display protocol to be used. Select either:
    • SPICE
    • VNC
    Select SPICE for Windows or Linux virtual machines. This is the recommended protocol. or select VNC for Linux virtual machines if desired.
    USB Policy Select Enabled or Disabled to indicate whether a USB device can be inserted into the client machine. The USB policy editor can be used to set up policies.
    Monitors
    For Windows virtual machines, the number of monitors that the virtual machine can have. Consider the processing and storage needs of the applications that are intended to run on the virtual machine.

  8. Enter information in the Host group if you wish to define the specific hosts on which the virtual machines are to be run and specific migration details.

    Table 8.5. New Pool Host Fields

    Field
    Description
    Notes
    Run On The host for the virtual machines to run on.
    • Select Any Host in Cluster if the virtual machines can run on any available host in the cluster.
    • Select Specific if the virtual machines are to run on a particular host in the cluster. Select the host from the list of available hosts in the cluster.
    Run/Migration Options Further options for running virtual machines
    • Select Run VM only on the selected Host to start and run the virtual machine only on the host specified in the Run On field.
    • Select Do not migrate VM to prevent migration in mid-operation to other hosts in the cluster, for example, in case of overload or fencing of the host. However, the virtual machine may start on any host.

  9. Enter information in the Resource Allocation group. This step specifies the storage requirements for all the virtual machines in the pool.

    Table 8.6. New Pool Allocation Fields

    Field
    Description
    Notes
    Storage Domain The name of the storage domain where the images of the virtual machines of the pool will be stored.  
    Provisioning The type of storage required for the virtual machines. Select either:
    • Thin
    • Clone
    Refer to Section 6.1.3, “Understanding Virtual Machine Storage” for a description of these options.
    Memory Allocation/Physical Memory Guarantee The amount of physical memory that must be reserved for this pool.  

  10. Enter information in the Boot Sequence fields to specify how the virtual machines are to attempt to boot.
    New Pool - Boot Options - Boot Sequence

    Figure 8.2. New Pool - Boot Options - Boot Sequence


    Table 8.7. New Pools Boot Device Sequence Fields

    Field
    Description
    Notes
    First Device
    • HardDisk
    • CD-ROM
    • Network (PXE)
    After installing a new virtual machine, the new virtual machine must go into Boot mode before powering up. Select the first device that the virtual machine must try to boot:
    • Hard Disk to boot from the hard disk (though if this is a blank virtual machine, it will obviously not boot from the hard disk)
    • CD-ROM to boot from the CD
    • Network (PXE) to boot from the network.
    Second Device Select the second device that the virtual machine must try to boot:
    • Hard Disk
    • CD-ROM
    • Network (PXE)
    Select the second device for the virtual machine to use to boot if the first device is not available. The first device selected in the previous option does not appear in the options.
    Attach CD A list of available CD-ROMs appear if Attach CD is selected. Select the appropriate operating system ISOs available on the system.
    Linux Boot Options If the virtual machine is a Linux machine, you can enter customized options for the kernel path,initrd path, kernel params (parameters).  

  11. Click OK. If any mandatory fields have been omitted, you are prompted to enter information. The required fields display with a red border. Enter the requisite information.
    A pool of the specified number of identical virtual machines is created. You can view these virtual machines in the Virtual Machines tab (on the Details pane), or on the main Virtual Machines tab. Note the icon denoting that the virtual machines are part of a pool. During creation, the desktops have a status of Image Locked, followed by a status of Down. You need to start the desktops in the Virtual Machines tab. See Chapter 6, Managing Virtual Resources.
    Desktop Pool VMs in the Details Pane

    Figure 8.3. Desktop Pool VMs in the Details Pane