Template File

A template is a TOML file with default values for a new VM instance. Pass it to cubic create or cubic run with --template. Create from a Template shows how to use one.

Every field except version is optional and falls back to the Cubic default when it is left out, see Names, Sizes and Defaults. A command line argument always wins over the template.

Field	Value	Description
`version`	`1`	Format version of the template. Mandatory.
`image`	name and tag, `"ubuntu:26.04"`	Distribution image of the VM instance. A plain name means the `stable` tag. Defaults to `ubuntu`. See Image Names.
`user`	user name, `"john"`	User account inside the guest. Defaults to your user name on the host.
`cpus`	number, `4`	vCPUs of the VM instance. Defaults to a value derived from the resources of the host.
`memory`	size, `"4G"`	Memory of the VM instance. Defaults to a value derived from the resources of the host.
`disk`	size, `"100G"`	Disk capacity of the VM instance. Defaults to 100 GiB. A disk can only grow later.
`isolate`	`true` or `false`	Cuts the VM instance off the network. Defaults to `false`.
`ports`	list of `"host:guest"`	Forwarded ports, with an optional protocol such as `"5353:53/udp"`.
`run`	list of shell commands	Commands the guest runs once on its first boot, as root.

Example

version = 1              # mandatory

image = "debian"         # optional
user = "john"            # optional
cpus = 4                 # optional
memory = "4G"            # optional
disk = "100G"            # optional
isolate = false          # optional

ports = [                # optional
  "8000:80",             # forward guest HTTP port to host TCP port 8000
  "5353:53/udp"          # forward guest DNS port to host UDP port 5353
]

run = [                  # optional, run once on the first boot as root
  "apt update",
  "apt full-upgrade -y",
  "apt install -y vim"
]