Use the Guest Customization wizard to save guest operating system settings in a specification that you can apply when cloning virtual machines or deploying from templates.


Ensure that all requirements for customization are met. See Guest Operating System Customization Requirements.


  1. From the vSphere Web Client Home inventory page, select Policies and Profiles > Customization Specification Manager.
  2. Click the Create a New specification icon.
  3. Select Linux from the Target VM Operating System drop-down menu, and enter a name and description for the specification.
  4. Enter the guest operating system's computer name.
    The operating system uses this name to identify itself on the network. On Linux systems, it is called the host name.
    Option Action
    Enter a name
    1. Type a name.

      The name can contain alphanumeric characters and the hyphen (-) character. It cannot contain periods (.) or blank spaces and cannot be made up of digits only. Names are not case-sensitive.

    2. (Optional) To ensure that the name is unique, select Append a numeric value to ensure uniqueness. This action appends a hyphen followed by a numeric value to the virtual machine name. The name is truncated if it exceeds 63 characters when combined with the numeric value.
    Use the virtual machine name The computer name that vCenter Server creates is identical to the name of the virtual machine on which the guest operating system is running. If the name exceeds 63 characters, it is truncated.
    Enter a name in the Clone/Deploy wizard The vSphere Web Client prompts you to enter a name after the cloning or deployment is complete.
    Generate a name using the custom application configured with vCenter Server Enter a parameter that can be passed to the custom application.
  5. Enter the Domain Name for the computer and click Next.
  6. Select the time zone for the virtual machine and click Next.
  7. Select the type of network settings to apply to the guest operating system.
    Option Action
    Standard settings

    Select Use standard network settings and click Next.

    vCenter Server configures all network interfaces from a DHCP server using default settings.

    Custom settings
    1. Select Manually select custom settings.
    2. For each network interface in the virtual machine, click the pencil icon.
  8. To specify IPv4 related settings, select IPv4 and enter IP address and other network settings.
  9. To specify IPv6 related settings, select IPv6 to configure the virtual machine to use IPv6 network.
    1. Select Prompt user for an address when the specification is used. Selecting this option prompts you to enter IPv6 address.
    2. Select Use the following IPv6 addresses to choose an IPv6 address from the list.
      • Click the pencil icon to enter additional IPv6 addresses. You can specify the full address or shorten it by using zero compression and zero suppression. You should specify at least one IPv6 address. You can edit an existing address, but should not duplicate existing IPv6 addresses.
      • Enter subnet mask prefix. The prefix length should be between 1 to 128 where the default value is 64. Gateway is enabled by default, except when you choose Do not use IPv6.
  10. Enter DNS and domain settings information. The Primary DNS, Secondary DNS, and Tertiary DNS fields accept both IPv4 and IPv6 addresses.
  11. Click Finish to save your changes.


The customization specification that you created is listed in the Customization Specification Manager. You can use the specification to customize virtual machine guest operating systems.