[image-guide] Reorder the image formats for alphabetical order

Change-Id: I07a521cf52ebb5659d6cd0befaaf886854187bbf

doc/image-guide/source/introduction.rst

@@ -24,17 +24,47 @@ that has a bootable operating system installed on it.
 Virtual machine images come in different formats, some of which are
 described below.
 
-Raw
+AKI/AMI/ARI
- The ``raw`` image format is the simplest one, and is natively
+ The `AKI/AMI/ARI
- supported by both KVM and Xen hypervisors.
+ <http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AMIs.html>`_
- You can think of a raw image as being the bit-equivalent of
+ format was the initial image format supported by Amazon EC2.
- a block device file, created as if somebody had copied, say,
+ The image consists of three files:
- ``/dev/sda`` to a file using the :command:`dd` command.
 
- .. note::
+ AKI (Amazon Kernel Image)
+  A kernel file that the hypervisor will load initially to boot the image.
+  For a Linux machine, this would be a ``vmlinuz`` file.
 
-    We do not recommend creating raw images by dd'ing block device
+ AMI (Amazon Machine Image)
-    files, we discuss how to create raw images later.
+  This is a virtual machine image in raw format, as described above.
+
+ ARI (Amazon Ramdisk Image)
+  An optional ramdisk file mounted at boot time.
+  For a Linux machine, this would be an ``initrd`` file.
+
+ISO
+ The `ISO
+ <http://www.ecma-international.org/publications/standards/Ecma-119.htm>`_
+ format is a disk image formatted with the read-only ISO 9660 (also known
+ as ECMA-119) filesystem commonly used for CDs and DVDs.
+ While we do not normally think of ISO as a virtual machine image format,
+ since ISOs contain bootable filesystems with an installed operating system,
+ you can treat them the same as you treat other virtual machine image files.
+
+OVF
+ `OVF <http://dmtf.org/sites/default/files/OVF_Overview_Document_2010.pdf>`_
+ (Open Virtualization Format) is a packaging format for virtual machines,
+ defined by the Distributed Management Task Force (DMTF) standards group.
+ An OVF package contains one or more image files, a .ovf XML metadata file
+ that contains information about the virtual machine, and possibly other
+ files as well.
+
+ An OVF package can be distributed in different ways. For example,
+ it could be distributed as a set of discrete files, or as a tar archive
+ file with an ``.ova`` (open virtual appliance/application) extension.
+
+ OpenStack Compute does not currently have support for OVF packages,
+ so you will need to extract the image file(s) from an OVF package
+ if you wish to use it with OpenStack.
 
 QCOW2
  The `QCOW2 <http://en.wikibooks.org/wiki/QEMU/Images>`_
@@ -55,22 +85,17 @@ QCOW2
     Because raw images do not support snapshots, OpenStack Compute
     will automatically convert raw image files to qcow2 as needed.
 
-AMI/AKI/ARI
+Raw
- The `AMI/AKI/ARI
+ The ``raw`` image format is the simplest one, and is natively
- <http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AMIs.html>`_
+ supported by both KVM and Xen hypervisors.
- format was the initial image format supported by Amazon EC2.
+ You can think of a raw image as being the bit-equivalent of
- The image consists of three files:
+ a block device file, created as if somebody had copied, say,
+ ``/dev/sda`` to a file using the :command:`dd` command.
 
- AMI (Amazon Machine Image)
+ .. note::
-  This is a virtual machine image in raw format, as described above.
 
- AKI (Amazon Kernel Image)
+    We do not recommend creating raw images by dd'ing block device
-  A kernel file that the hypervisor will load initially to boot the image.
+    files, we discuss how to create raw images later.
-  For a Linux machine, this would be a ``vmlinuz`` file.
-
- ARI (Amazon Ramdisk Image)
-  An optional ramdisk file mounted at boot time.
-  For a Linux machine, this would be an ``initrd`` file.
 
 UEC tarball
  A UEC (Ubuntu Enterprise Cloud) tarball is a gzipped tarfile that
@@ -82,11 +107,6 @@ UEC tarball
     Ubuntu cloud solution that has been replaced by the OpenStack-based
     Ubuntu Cloud Infrastructure.
 
-VMDK
- VMware ESXi hypervisor uses the
- `VMDK <https://developercenter.vmware.com/web/sdk/60/vddk>`_
- (Virtual Machine Disk) format for images.
-
 VDI
  VirtualBox uses the
  `VDI <https://forums.virtualbox.org/viewtopic.php?t=8046>`_
@@ -103,27 +123,7 @@ VHDX
  which has some additional features over VHD such as support for larger disk
  sizes and protection against data corruption during power failures.
 
-OVF
+VMDK
- `OVF <http://dmtf.org/sites/default/files/OVF_Overview_Document_2010.pdf>`_
+ VMware ESXi hypervisor uses the
- (Open Virtualization Format) is a packaging format for virtual machines,
+ `VMDK <https://developercenter.vmware.com/web/sdk/60/vddk>`_
- defined by the Distributed Management Task Force (DMTF) standards group.
+ (Virtual Machine Disk) format for images.
- An OVF package contains one or more image files, a .ovf XML metadata file
- that contains information about the virtual machine, and possibly other
- files as well.
-
- An OVF package can be distributed in different ways. For example,
- it could be distributed as a set of discrete files, or as a tar archive
- file with an ``.ova`` (open virtual appliance/application) extension.
-
- OpenStack Compute does not currently have support for OVF packages,
- so you will need to extract the image file(s) from an OVF package
- if you wish to use it with OpenStack.
-
-ISO
- The `ISO
- <http://www.ecma-international.org/publications/standards/Ecma-119.htm>`_
- format is a disk image formatted with the read-only ISO 9660 (also known
- as ECMA-119) filesystem commonly used for CDs and DVDs.
- While we do not normally think of ISO as a virtual machine image format,
- since ISOs contain bootable filesystems with an installed operating system,
- you can treat them the same as you treat other virtual machine image files.