openstack/nova
Code Issues Proposed changes

Fix list rendering in bdm doc.

Browse Source 
What looked clear in the rst actually was far from clear when rendered
in HTML. The document was restructured a bit so all the options end up
in a single bullet list, and the combination description is a separate
section.

Part of bp: doc-migration

Change-Id: I2feee4018a332483658d24d299dbb04ec87f2df0
This commit is contained in:
Sean Dague 2017-08-03 07:59:41 -04:00
parent dafd133ab8
commit 3361769910
1 changed files with 41 additions and 37 deletions
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78
doc/source/user/block-device-mapping.rst
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@ -122,43 +122,15 @@ fields (in addition to the ones that were already there):
* source_type - this can have one of the following values:
* `image`
* `volume`
* `snapshot`
* `blank`
* `image`
* `volume`
* `snapshot`
* `blank`
* dest_type - this can have one of the following values:
* `local`
* `volume`
Combination of the above two fields would define what kind of block device the
entry is referring to. We currently support the following combinations:
* `image` -> `local` - this is only currently reserved for the entry
referring to the Glance image that the instance is being booted with (it
should also be marked as a boot device). It is also worth noting that an
API request that specifies this, also has to provide the same Glance uuid
as the `image_ref` parameter to the boot request (this is done for
backwards compatibility and may be changed in the future). This
functionality might be extended to specify additional Glance images
to be attached to an instance after boot (similar to kernel/ramdisk
images) but this functionality is not supported by any of the current
drivers.
* `volume` -> `volume` - this is just a Cinder volume to be attached to the
instance. It can be marked as a boot device.
* `snapshot` -> `volume` - this works exactly as passing `type=snap` does.
It would create a volume from a Cinder volume snapshot and attach that
volume to the instance. Can be marked bootable.
* `image` -> `volume` - As one would imagine, this would download a Glance
image to a cinder volume and attach it to an instance. Can also be marked
as bootable. This is really only a shortcut for creating a volume out of
an image before booting an instance with the newly created volume.
* `blank` -> `volume` - Creates a blank Cinder volume and attaches it. This
will also require the volume size to be set.
* `blank` -> `local` - Depending on the guest_format field (see below),
this will either mean an ephemeral blank disk on hypervisor local
storage, or a swap disk (instances can have only one of those).
* `local`
* `volume`
* guest_format - Tells Nova how/if to format the device prior to attaching,
should be only used with blank local images. Denotes a swap disk if the value
@ -189,10 +161,42 @@ entry is referring to. We currently support the following combinations:
usage is to set it to 0 for the boot device and leave it as None for any
other devices.
Valid source / dest combinations
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Nova will not allow mixing of two formats in a single request, and will do
basic validation to make sure that the requested block device mapping is valid
before accepting a boot request.
Combination of the ``source_type`` and ``dest_type`` will define the
kind of block device the entry is referring to. The following
combinations are supported:
* `image` -> `local` - this is only currently reserved for the entry
referring to the Glance image that the instance is being booted with
(it should also be marked as a boot device). It is also worth noting
that an API request that specifies this, also has to provide the
same Glance uuid as the `image_ref` parameter to the boot request
(this is done for backwards compatibility and may be changed in the
future). This functionality might be extended to specify additional
Glance images to be attached to an instance after boot (similar to
kernel/ramdisk images) but this functionality is not supported by
any of the current drivers.
* `volume` -> `volume` - this is just a Cinder volume to be attached to the
instance. It can be marked as a boot device.
* `snapshot` -> `volume` - this works exactly as passing `type=snap` does.
It would create a volume from a Cinder volume snapshot and attach that
volume to the instance. Can be marked bootable.
* `image` -> `volume` - As one would imagine, this would download a Glance
image to a cinder volume and attach it to an instance. Can also be marked
as bootable. This is really only a shortcut for creating a volume out of
an image before booting an instance with the newly created volume.
* `blank` -> `volume` - Creates a blank Cinder volume and attaches it. This
will also require the volume size to be set.
* `blank` -> `local` - Depending on the guest_format field (see below),
this will either mean an ephemeral blank disk on hypervisor local
storage, or a swap disk (instances can have only one of those).
Nova will not allow mixing of BDMv1 and BDMv2 in a single request, and
will do basic validation to make sure that the requested block device
mapping is valid before accepting a boot request.
.. [1] In addition to the BlockDeviceMapping Nova object, we also have the
BlockDeviceDict class in :mod: `nova.block_device` module. This class