Image

Overview

An image is an image template used by a VM instance or volume.

Image templates include root volume images and data volume images.
Root volume images can be in the format of ISO or Image, while data volume images can be in the format of Image.
The Image format can either be raw or qcow2.
Images are stored on backup storage. If you are creating VM instances or volumes for the first time, the images will be downloaded to primary storage and stored as image caches.

When you create a VM instance, the type of the image platform decides whether to use a KVM Virtio driver (including disk driver and NIC driver). The supported image platforms are as follows:

Linux: Uses a Virtio driver.
Windows: Not to use a Virtio driver. Instead, QEMU is used. The image operating system is a Windows OS without a Virtio driver installed.
WindowsVirtio: Uses a Virtio driver. The image operating system is a Windows OS with a Virtio driver (including disk driver and NIC driver) installed.
Other: Not to use a Virtio driver. Instead, QEMU is used. The image operating system can be of any types.
Paravirtualization: Uses a Virtio driver. The image operating system can be any operating system with a Virtio driver installed.

To add an image, add a URL or upload a local file.

URL: Adds an image through the specified URL.
- HTTP/HTTPS:
  - Format: http://path/file or https://path/file
  - Example: http://cdn.zstack.io/product_downloads/images/zstack-image.qcow2
- FTP:
  - Anonymous format: ftp://hostname[:port]/path/file
    Example: ftp://172.20.0.10/pub/zstack-image.qcow2
  - Non-anonymous format: ftp://user:password@hostname[:port]/path/file
    Example: ftp://zstack:password@172.20.0.10/pub/zstack-image.qcow2
- SFTP:
  - Format with password specified: sftp://user:password@hostname[:port]/path/file
    Example: sftp://root:password@172.20.0.10/pub/zstack-image.qcow2
  - Password-free format: sftp://user@hostname[:port]/path/file
    Example: sftp://root@172.20.0.10/pub/zstack-image.qcow2
- The absolute path on backup storage, which supports SFTP backup storage and ImageStore.
  Example: file:///opt/zstack-dvd/zstack-image-1.4.qcow2
Note:
- Before you enter a URL, make sure that the URL can be accessed by a backup storage and the corresponding backup storage file exists.
- Before you upload an image by using the SFTP password-free method, make sure that password-free SSH access can be achieved between a backup storage and the SFTP server.
- Smooth, continuous display of progress bar, and breakpoint resume:
  - The ImageStore backup storage supports smooth, continuous display of progress bar, and breakpoint resume.
  - The Ceph backup storage supports smooth, continuous display of progress bar, but does not support breakpoint resume.
  - The SFTP backup storage does not support smooth, continuous display of progress bar, or breakpoint resume.
- If you upload an image by using file:///, make sure that:
  - The Ceph backup storage currently does not support the file:/// format.
  - The file:/// path contains three forward slashes (/), which correspond to the absolute path of the backup storage. For example, file:///opt/zstack-dvd/zstack-image-1.4.qcow2. The zstack-image-1.4.qcow2 file needs to be stored in the /opt/zstack-dvd directory of the backup storage.
Upload a local file: You can upload an image that can be accessed by your current browser. Both ImageStore and Ceph backup storages are supported.
Note:
When you add an image by uploading a local file, you use the local browser as a transit point. Therefore, do not refresh or close the current browser, and do not stop the management node service. Otherwise, the image might fail to be added.

Inventory

Properties

Name	Description	Optional	Optional Value	Starting Version
uuid	The UUID. For more information, see Resource Property.			0.6
name	The name. For more information, see Resource Property.			0.6
description	The description. For more information, see Resource Property.	Yes		0.6
state	The state. For more information, see State.		Enabled Disabled	0.6
status	The status. For more information, see Status.		Creating Downloading Ready	0.6
size	The image size. Unit: byte.			0.6
url	The URL from which the image is registered. For more information, see URL.			0.6
mediaType	The image media type. For more information, see Media Type.		RootVolumeTemplate DataVolumeTemplate ISO	0.6
guestOsType	The string that describes the operating system type of a VM instance.	Yes		0.6
platform	The platform of a VM instance's operating system. For more information, see Platform.		Linux Windows Paravirtualization Other	0.6
system	Whether the image is a system image. For more information, see System Image.			0.6
format	The format. For more information, see Format.		qcow2 raw	0.6
md5Sum	The MD5 checksum of the image.			0.6
type	The reserved field.		zstack	0.6
actualSize	The actual size.			0.6
exportMd5Sum				0.6
exportUrl				0.6
backupStorageRefs	The backup storage references. For more information, see Back Storage Reference.			0.6
createDate	The creation date. For more information, see Resource Property.			0.6
lastOpDate	The last operation date. For more information, see Resource Property.			0.6

Sample

{     "inventories": [         {             "actualSize": 293641216,             "backupStorageRefs": [                 {                     "backupStorageUuid": "ae840e03a0044b759b0a8c09a141a46b",                     "createDate": "Oct 30, 2017 4:32:11 PM",                     "imageUuid": "fccc12fee6a411d68c42763ded705630",                     "installPath": "zstore://fccc12fee6a411d68c42763ded705630/b08ea6cad1f10217223192343a1d8fb72279ed47",                     "lastOpDate": "Oct 30, 2017 4:32:11 PM",                     "status": "Ready"                 }             ],             "createDate": "Oct 30, 2017 4:32:11 PM",             "description": "",             "exportMd5Sum": "9b38fe1fd43385b86a1c9b12ac1960fe",             "exportUrl": "http://10.0.146.122:8001/imagestore/download/image-b08ea6cad1f10217223192343a1d8fb72279ed47.qcow2",             "format": "qcow2",             "lastOpDate": "Oct 30, 2017 7:35:38 PM",             "md5Sum": "42e98b8fc79cd8aeffe1b34a2a7021fed621eec0be926139d46e8afc26e78b7d",             "mediaType": "RootVolumeTemplate",             "name": "vr-test-2",             "platform": "Linux",             "size": 8589934592,             "state": "Enabled",             "status": "Ready",             "system": true,             "type": "zstack",             "url": "http://192.168.200.100/mirror/diskimages/zstack-vrouter-latest.qcow2",             "uuid": "fccc12fee6a411d68c42763ded705630"         }     ],     "success": true }

State

An image has the following two states:

Enabled:
Indicates that VM instances can be created from this image.
Disabled:
Indicates that VM instances cannot be created from this image.

Status

Status indicates the lifecycle of an image.

Creating:
Indicates that the image is being created from a volume, and is not ready to use.
Downloading:
Indicates that the image is being downloaded from a URL, and is not ready to use.
Ready:
Indicates that the image already exists in backup storage, and is ready to use.

URL

The meaning of a URL varies depending on how an image was created on a backup storage.

If the image was downloaded from a web server, the URL is an HTTP/HTTPS link.
If the image was created from a volume or a volume snapshot, the URL is a string encoding UUID of the volume or the volume snapshot. For example,
```
volume://b395386bdb4a4ff1b1850a457c949c5e volumeSnapshot://b395386bdb4a4ff1b1850a457c949c5e
```

Media Type

Media type indicates how an image will be used.

RootVolumeTemplate:
This type of image is used to create root volumes.
DataVolumeTemplate:
This type of image is used to create data volumes.
ISO:
ISO images are used to install operating systems on blank root volumes.

Platform

Platform gives ZStack a hint that whether to use paravirtualization.

Use paravirtualization	Linux Paravirtualization
Not to use paravirtualization (The VM instance disk uses the IDE mode, and the NIC uses e1000.)	Windows Other

System Image

System images are used only for appliance VM instances, not for user VM instances.

Format

Format reveals the relationship between hypervisors and images. For example, images of qcow2 format can only be used for KVM VM instances. The current version of ZStack supports only KVM hypervisors. The relationship is as follows.

Hypervisor Type	Format
KVM	qcow2 raw

Volumes will inherit formats of images from which they are created. For example, the root volumes created from images of qcow2 format will also have the qcow2 format. The raw format is an exception. The volumes created from raw images will have the qcow2 format because ZStack will perform thin clone by using the qcow2 format.

Backup Storage Reference

An image can be stored on more than one backup storage. For each backup storage, the image has a backup storage reference that includes the backup storage UUID and the image installation path.

Name	Description	Starting Version
imageUuid	The image UUID.	0.6
backupStorageUuid	The backup storage UUID. For more information, see Backup Storage.	0.6
installPath	The installation path on the backup storage.	0.6
createDate	The creation date. For more information, see Resource Property.	0.6
lastOpDate	The last operation date. For more information, see Resource Property.	0.6

Sample

{                     "backupStorageUuid": "ae840e03a0044b759b0a8c09a141a46b",                     "createDate": "Oct 30, 2017 4:32:11 PM",                     "imageUuid": "fccc12fee6a411d68c42763ded705630",                     "installPath": "zstore://fccc12fee6a411d68c42763ded705630/b08ea6cad1f10217223192343a1d8fb72279ed47",                     "lastOpDate": "Oct 30, 2017 4:32:11 PM",                     "status": "Ready"                 }