instantiateFrom

Specifies whether to include the disk and what image to use. Possible values are: - source-image: to use the same image that was used to create the source instance's corresponding disk. Applicable to the boot disk and additional read-write disks. - source-image-family: to use the same image family that was used to create the source instance's corresponding disk. Applicable to the boot disk and additional read-write disks. - custom-image: to use a user-provided image url for disk creation. Applicable to the boot disk and additional read-write disks. - attach-read-only: to attach a read-only disk. Applicable to read-only disks. - do-not-include: to exclude a disk from the template. Applicable to additional read-write disks, local SSDs, and read-only disks.