Deploying OpenStack

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.