cloudinit/Documentation/vmware-backdoor.md

VMware Backdoor

Cloud-Config Options List

coreos-cloudinit is capable of reading userdata and metadata from the VMware backdoor. This datasource can be enabled with the --from-vmware-backdoor flag. Userdata and metadata are passed from the hypervisor to the virtual machine through guest variables. The following guest variables and their expected types are supported by coreos-cloudinit:

guest variable	type
hostname	hostname
interface.<n>.name	string
interface.<n>.mac	MAC address
interface.<n>.dhcp	{"yes", "no"}
interface.<n>.role	{"public", "private"}
interface.<n>.ip.<m>.address	CIDR IP address
interface.<n>.route.<l>.gateway	IP address
interface.<n>.route.<l>.destination	CIDR IP address
dns.server.<x>	IP address
coreos.config.data	string
coreos.config.data.encoding	{"", "base64", "gzip+base64"}
coreos.config.url	URL

Note: "n", "m", "l", and "x" are 0-indexed, incrementing integers. The identifier for the interfaces does not correspond to anything outside of this configuration; it is merely for mapping configuration values to each interface.

Please refer to link to know more how to run CoreOS on VMware.