Image Definition Template 4.4
This page describes how to define a new image template. An image template follows the same syntax as the VM template.
If you want to learn more about the image repository, you can do so here.
There are some template attributes that 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, the default ones are labeled with * in the following tables. See the complete list in the Restricted Attributes section.
Template Attributes
The following attributes can be defined in the template.
| Attribute | M / O | 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, KERNEL, RAMDISK, CONTEXT | 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 | An special persistent image, that will not be modified. This attribute should only be used for special storage configurations. |
| DEV_PREFIX | Optional | Any string | 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. |
| DRIVER | Optional | KVM: raw, qcow2 Xen:tap:aio:, file: | Specific image mapping driver. VMware is unsupported |
| PATH | Mandatory (if no SOURCE) | Any string | Path to the original file (it can be gz compressed) that will be copied to the image repository. If not specified for a DATABLOCK type image, an empty image will be created. |
| SOURCE* | Mandatory (if no PATH) | Any string | Source to be used in the DISK attribute. Useful for not 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. |
| CLONE_FSTYPE | Optional | thin,zeroedthick,eagerzeroedthick , thick,thin | Only for VMware images ion vmfs datastores. Sets the format of the target image when cloning within the datstore. More information on types. |
Mandatory attributes for DATABLOCK images with no PATH set:
| Attribute | Value | Description |
|---|---|---|
| SIZE | An integer | Size in MB. |
| FSTYPE | String | Type of file system to be built. Plain. When the disk image is used directly by the hypervisor we can format the image, and so it is ready to be used by the guest OS. Values: ext2, ext3, ext4, ntfs, reiserfs, jfs, swap. Any other fs supported by mkfs will work if no special option is needed. Formatted. The disk image is stored in a hypervisor specific format VMDK or Qcow2. Then we cannot really make a filesystem on the image, just create the device and let the guest OS format the disk. Use raw to not to format the new image. Values: raw, qcow2, vmdk_*. |
Template Examples
Example of an OS image: <xterm> 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.” </xterm>
Example of a CDROM image: <xterm> 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.” </xterm>
Example of a DATABLOCK image: <xterm> NAME = “Experiment results” TYPE = DATABLOCK # No PATH set, this image will start as a new empty disk SIZE = 3.08 FSTYPE = ext3 DESCRIPTION = “Storage for my Thesis experiments.” </xterm>
Restricted Attributes
All the default restricted attributes to users in the oneadmin group are summarized in the following list:
- SOURCE