Image Template

This page describes how to define a new image template. An image template follows the same syntax as the VM template.

Warning

Some template attributes can compromise the security of the system or the security of other VMs, and can be used only by users in the oneadmin group. These attributes can be configured in oned.conf. In the following tables, default attributes are marked with *. For the complete list, see the Restricted Attributes section.

Template Attributes

The following attributes can be defined in the template:

Attribute	KVM	Value	Description
`NAME`	Mandatory	Any string	Name that the image will get. Every image must have a unique name.
`DESCRIPTION`	Optional	Any string	Human readable description of the image for other users.
`TYPE`	Optional	`OS`, `CDROM`, `DATABLOCK` for VM disks; `KERNEL`, `RAMDISK`, `CONTEXT` for File Datastores	Type of the image, explained in detail in the following section. If omitted, the default value is the one defined in oned.conf (install default is OS)
`PERSISTENT`	Optional	`YES`, `NO`	Persistence of the image. If omitted, the default value is `NO`.
`PERSISTENT_TYPE`	Optional	`IMMUTABLE`, `SHAREABLE`	`IMMUTABLE` - A special persistent image, that will not be modified. `SHAREABLE` - Persistent image shareable by multiple VMs. Requires `raw` image `FORMAT` and shared datastore. Virtualization driver needs `SUPPORT_SHAREABLE = "yes"` This attribute should only be used for special storage configurations.
`DEV_PREFIX`	Optional	Any string e.g `sd`, `hd`	Prefix for the emulated device this image will be mounted at. For instance, `hd`, `sd`, or `vd` for KVM virtio. If omitted, the default value is the one defined in oned.conf (installation default is `hd`).
`TARGET`	Optional	Any string	Target for the emulated device this image will be mounted at. For instance, `hdb`, `sdc`. If omitted, it will be assigned automatically.
`FORMAT`	Optional	`raw` or `qcow2`	Format of the image backing file.
`FS`	Optional	File system name (e.g ext4, xfs, …)	Specific file system type. It is used for formatting datablocks and volatile disks.
`PATH`	Mandatory (if no SOURCE)	Any string	Path to the original file that will be copied to the image repository. If not specified for a `DATABLOCK` type image, an empty image will be created. Note that gzipped files are supported and OpenNebula will automatically decompress them. Bzip2 compressed files is also supported, but it’s strongly discouraged since OpenNebula will not calculate its size properly.
`SOURCE\*`	Mandatory (if no PATH)	Any string	Source to be used in the DISK attribute. Useful for non file-based images.
`DISK_TYPE`	Optional	`BLOCK`, `CDROM` or `FILE` (default).	This is the type of the supporting media for the image: a block device (`BLOCK`) an ISO-9660 file or readonly block device (`CDROM`) or a plain file (`FILE`).
`READONLY`	Optional	`YES`, `NO`	This attribute should only be used for special storage configurations. It sets how the image is going to be exposed to the hypervisor. Images of type `CDROM` and those with PERSISTENT_TYPE set to `IMMUTABLE` will have `READONLY` set to `YES`. Otherwise, by default it is set to `NO`.
`MD5`	Optional	An MD5 hash	MD5 hash to check for image integrity.
`SHA1`	Optional	An SHA1 hash	SHA1 hash to check for image integrity.
`LUKS_SECRET`	Optional	UUID value	This attribute needs to be set for LUKS-encrypted images. Its value is UUID registered on hypervisor nodes as an identifier for the LUKS secret.
`SERIAL`	Optional	`auto`, any string	If present, a serial number will be added to virtual hard drive. If set to `auto`, the serial number will be generated automatically. (<vm_id>-<disk_id>) If set to a specific value, that value will be used as the serial number.

Warning

Be careful when PATH points to a compressed bz2 image, since although it will work, OpenNebula will not calculate its size correctly.

Important

All of the above KVM attributes also apply to LXC, with the exception of DEV_PREFIX and TARGET.

Mandatory attributes for DATABLOCK images with no PATH set:

Attribute	Value	Description
`SIZE`	An integer	Size in MB.

Template Examples

Example of an OS image:

NAME          = "Ubuntu Web Development"
PATH          = /home/one_user/images/ubuntu_desktop.img
DESCRIPTION   = "Ubuntu 10.04 desktop for Web Development students.
Contains the pdf lessons and exercises as well as all the necessary
programming tools and testing frameworks."

Example of a CDROM image:

NAME          = "MATLAB install CD"
TYPE          = CDROM
PATH          = /home/one_user/images/matlab.iso
DESCRIPTION   = "Contains the MATLAB installation files. Mount it to install MATLAB on new OS images."

Example of a DATABLOCK image:

NAME          = "Experiment results"
TYPE          = DATABLOCK
# No PATH set, this image will start as a new empty disk
SIZE          = 3.08
DESCRIPTION   = "Storage for my Thesis experiments."

Restricted Attributes

All the default restricted attributes to users in the oneadmin group are summarized in the following list:

SOURCE

These attributes can be configured in oned.conf.

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