Image Support
Glance supports a wide array of virtual disk and container formats. Virtual disks are analogous to a physical server’s boot drives, only condensed into a file. Different virtualization technologies support different disk formats. Glance supports the disk formats shown in Table 3-2.
Table 3-2. Glance Supported Disk Formats
| Disk Format | Notes |
|---|---|
| Raw | Unstructured disk format |
| VHD | Most common format supported by most OpenStack virtualization technologies except KVM. |
| VMDK | Format popularized by VMware. |
| qcow2 | QEMU image format, native format for KVM and QEMU. Supports advanced functions. |
| VDI | Virtual disk image format originated by Oracle VM VirtualBox. |
| ISO | Archive format for optical disks. |
| AMI, ARI, AKI | Amazon machine, ramdisk, and kernel images (respectively). See more information at the Amazon EC2 User Guide. |
Glance also supports the concept of container formats, which describes the file format and contains additional metadata. Glance supports two container formats as well as the absence of a container format (bare), as shown in Table 3-3.
Table 3-3. Glance Container Formats
| Container Format | Notes |
|---|---|
| OVF | An open standard for distributing one or more virtual machine images. Read more about this standard at http://www.dmtf.org/standards/ovf. |
| aki, ari, ami | Amazon kernel, ramdisk, or machine image (respectively). Read more about these container formats at Amazon EC2 User Guide. |
| Bare | No container for this image. |