A Docker image is a tar archive typically containing a container filesystem. In order to use the nova-docker compute driver nova and boot docker instances glance support of the docker container format is required. This patch adds the Docker container format to the Glance configuration. DocImpact: Docs will need to be updated to indicate that the docker container_format is now one of the default container formats supported by Glance. UpgradeImpact: Adds 'docker' to the default list of container_formats. Operators will no longer need to configure specifically to use docker containers. Closes-Bug: #1519402 Change-Id: Ifa206686086232a5599e7bc27a852bc5f3186ebc
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Disk and Container Formats
When adding an image to Glance, you must specify what the virtual machine image's disk format and container format are. Disk and container formats are configurable on a per-deployment basis. This document intends to establish a global convention for what specific values of disk_format and container_format mean.
Disk Format
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.
You can set your image's disk format to one of the following:
raw
This is an unstructured disk image format
vhd
This is the VHD disk format, a common disk format used by virtual machine monitors from VMWare, Xen, Microsoft, VirtualBox, and others
vmdk
Another common disk format supported by many common virtual machine monitors
vdi
A disk format supported by VirtualBox virtual machine monitor and the QEMU emulator
iso
An archive format for the data contents of an optical disc (e.g. CDROM).
qcow2
A disk format supported by the QEMU emulator that can expand dynamically and supports Copy on Write
aki
This indicates what is stored in Glance is an Amazon kernel image
ari
This indicates what is stored in Glance is an Amazon ramdisk image
ami
This indicates what is stored in Glance is an Amazon machine image
Container Format
The container format refers to whether the virtual machine image is in a file format that also contains metadata about the actual virtual machine.
Note that the container format string is not currently used by Glance or other OpenStack components, so it is safe to simply specify bare as the container format if you are unsure.
You can set your image's container format to one of the following:
bare
This indicates there is no container or metadata envelope for the image
ovf
This is the OVF container format
aki
This indicates what is stored in Glance is an Amazon kernel image
ari
This indicates what is stored in Glance is an Amazon ramdisk image
ami
This indicates what is stored in Glance is an Amazon machine image
ova
This indicates what is stored in Glance is an OVA tar archive file
docker
This indicates what is stored in Glance is a Docker tar archive of the container filesystem