Disk and container formats for images

Disk and container formats for images

When you add an image to the Image service, you can specify its disk and container formats.

Disk formats

The disk format of a virtual machine image is the format of the underlying disk image. Virtual appliance vendors have different formats for laying out the information contained in a virtual machine disk image.

Set the disk format for your image to one of the following values:

aki

An Amazon kernel image.

ami

An Amazon machine image.

ari

An Amazon ramdisk image.

iso

An archive format for the data contents of an optical disc, such as CD-ROM.

ploop

A kernel block device, similar to the traditional loop device but with more features added, such as dynamic disk space allocation, stackable images, online resize, snapshotting, and live migration helper.

qcow2

Supported by the QEMU emulator that can expand dynamically and supports Copy on Write.

raw

An unstructured disk image format; if you have a file without an extension it is possibly a raw format.

vdi

Supported by VirtualBox virtual machine monitor and the QEMU emulator.

vhd

The VHD disk format, a common disk format used by virtual machine monitors from VMware, Xen, Microsoft, VirtualBox, and others.

vhdx

The VHDX disk format, an enhanced version of the VHD format, which supports larger disk sizes among other features.

vmdk

Common disk format supported by many common virtual machine monitors.

Container formats

The container format indicates whether the virtual machine image is in a file format that also contains metadata about the actual virtual machine.

Note

The Image service and other OpenStack projects do not currently support the container format. It is safe to specify bare as the container format if you are unsure.

You can set the container format for your image to one of the following values:

aki

An Amazon kernel image.

ami

An Amazon machine image.

ari

An Amazon ramdisk image.

bare

The image does not have a container or metadata envelope.

docker

A docker container format.

ova

An OVF package in a tarfile.

ovf

The OVF container format.

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