The syntax of the template file is as follows:

• Anything behind the pound or hash sign (#) is a comment.
• Strings are delimited with double quotes (“), if the a double quote is part of the string it needs to be escaped (\”).
• Single Attributes are in the form:

NAME=VALUE

• Vector Attributes that contain several values can be defined as follows:

NAME=[NAME1=VALUE1,NAME2=VALUE2...]

• Vector Attributes must contain at least one value.
• Attribute names are case insensitive, in fact the names are converted to uppercase internally.

This template uses the most common functionality. The following sections briefly explain each attribute.

#### Capacity ####
 
NAME   = test-vm
MEMORY = 128 
CPU    = 1
 
#### Disks ####
 
# OS image, mapped to sda.
DISK = [ IMAGE_ID  = 2 ]
 
# First DATABLOCK image, mapped to sde
DISK = [ IMAGE_ID  = 3 ]
 
# Second DATABLOCK image, mapped to sdf
DISK = [ IMAGE_ID  = 12 ]
 
# swap, sdd
DISK = [ TYPE     = swap,
         SIZE     = 1024 ]
 
#### Network interfaces ####
 
NIC = [ NETWORK_ID = 1 ]
 
#### I/O Devices ####
 
GRAPHICS = [ 
  TYPE    = "vnc",
  LISTEN  = "0.0.0.0",
  PORT    = "5"]

The following attributes can be defined to specify the capacity of a VM.

The disks of a VM are defined with the DISK vector attribute. You can define as many DISK attributes as you need.

There are two ways to attach a disk to a VM: using an OpenNebula image from the image repository, or declaring a disk type that can be created from a source disk file in your system. This guide assumes that you will only use Images from the repository (can be listed with oneimage list).

To use the registered images in your VMs, you need to specify the IMAGE_ID sub-attribute.

Once the VM machine is shut down, the changes made to the images can be saved back to the repository. To do so, make your Images persistent, or use the onevm saveas command to save the changes as a new Image.

In a similar way that you can create empty datablock Images, VM disks can be created on the fly. This is specially useful to create swap disks.

When you use images in your VM template, OpenNebula will mount the disks as follows:

• sda: OS type Image.
• sdb: Contextualization CDROM.
• sdc: CDROM type Image.
• sdd: Swap disk.
• sd[e,f,g…]: DATABLOCK type Images.

Only one OS type image per VM template can be declared, the same applies for CDROM type images. You can use as many DATABLOCK images as you need. Please visit the guide for managing images and the image template reference to learn more about the different image types.

You can find a complete description of the contextualization features in the contextualization guide.

The device prefix sd can be changed to hd or other prefix that suits your virtualization hypervisor requirements. You can find more information in the configuration guide and the daemon configuration guide.

For more information on image management and moving please check the Storage guide.

Each network interface of a VM is defined with the NIC vector attribute. You can define as many NIC attributes as you need.

For more information on setting up virtual networks please check the Managing Virtual Networks guide.

The following I/O interfaces can be defined for a VM:

Note the hypervisor column states that the attribute is Optional, Mandatory, or - not supported for that hypervisor

For KVM hypervisor the port number is a real one, not the VNC port. So for VNC port 0 you should specify 5900, for port 1 is 5901 and so on.

If the user does not specify the port variable, OpenNebula will automatically assign $VNC_BASE_PORT + $VMID, allowing to generate different ports for VMs so they do not collide. The VNC_BASE_PORT is specified inside the oned.conf file.