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. In the vSphere Web Client inventory, select Rules and Profiles > Customization Specification Manager and click VM Customization Specifications.
  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. On the Computer name page, enter a computer name for the guest operating system and a domain name.
    The operating system uses the computer name to identify itself on the network. On Linux systems, it is called the host name.
    Option Action
    Use the virtual machine name Select to 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 Select to be prompted to enter a name during cloning or deployment.
    Enter a name
    1. Enter a name.

      The name can contain alphanumeric characters and a hyphen (-). It cannot contain a period (.), blank spaces, or special characters, and cannot contain digits only. Names are not case-sensitive.

    2. (Optional) To ensure that the name is unique, select the Append a numeric value check box.

      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.

    Generate a name using the custom application configured with vCenter Server Optional: Enter a parameter that can be passed to the custom application.
  5. Enter the Domain Name for the computer and click Next.
  6. On the Time zone page, select the time zone for the virtual machine and click Next.
  7. On the Configure Network page, 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. Select a network adapter from the list or add a new one.
    3. For the selected network interface in the virtual machine, click the pencil icon.

      The Edit Network dialog box opens.

    4. In the Edit Network dialog box, configure the network settings for the selected network interface.
    5. Click OK to save your configuration and close the Edit Network dialog box.
  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.