Dan Smith
e28f90866b
Long ago, it was decided that we should create an empty image in glance for snapshots of volume-backed instances[1]. I'm not really sure why that is, since it doesn't seem to be a useful construct to do anything with (like a normal snapshot, which can be used to boot). It was so long ago that it was not documented well[2]. However, when glance v2 came along, that sort of nonsensical thing became harder because images would not be "active" until they had content, and nova decided to continue the status quo by uploading empty data[3] to force the state transition. Later, that stopped working for Xen because we were lying about the format in a way that didn't work for Xen, so we made that lie dynamic[4] to triple-down on the original decision. Now, with glance moving to image format safety, our lies have caught up with us. We can no longer upload an empty stream of data and claim that it is qcow2 because glance will call our bluff. Although it was originally suggested[5] as a fix that would be hypervisor-neutral (and not implemented that way for reasons that were not stated), we must start uploading that empty stream as the 'raw' format that it is in order for glance to accept it. Technically glance can be configured to not allow raw uploads, which means that we could again end up with the situation from the xen bug[5], but without synthesizing a fictitious image of a type that is supported, there's no good solutuon, other than a re-think. I think it would be worth revisiting whether or not we need an empty glance image for volume-backed server snapshots, and if we do, whether or not there's a better way to go about that (like adding a location which will indicate it lives elsewhere and will result in it becoming active). However, in the meantime we need to be truthful about the lie we're making, by correctly identifying the format of the zero- length data we're not uploading. Needed-By: https://review.opendev.org/c/openstack/glance-specs/+/925111 Change-Id: I6a6184da3b73506261c61005b6984c69cdc7fb98 1: https://github.com/openstack/nova/commit/c3476b5ca7ab5237d3cb8a84fcb7a3292237b764 2: https://bugs.launchpad.net/nova/+bug/1034730 3: https://github.com/openstack/nova/commit/4a39b8b530b32337749a9e2d2a438b7b2f3430d8 4: https://github.com/openstack/nova/commit/2fe5daeb5fcd2750b0eb083fc5c8bfd3fdb992e2 5: https://bugs.launchpad.net/nova/+bug/1616938/comments/1
==============
OpenStack Nova
==============
.. image:: https://governance.openstack.org/tc/badges/nova.svg
:target: https://governance.openstack.org/tc/reference/tags/index.html
.. Change things from this point on
OpenStack Nova provides a cloud computing fabric controller, supporting a wide
variety of compute technologies, including: libvirt (KVM, Xen, LXC and more),
VMware and OpenStack Ironic.
Use the following resources to learn more.
API
---
To learn how to use Nova's API, consult the documentation available online at:
- `Compute API Guide <https://docs.openstack.org/api-guide/compute/>`__
- `Compute API Reference <https://docs.openstack.org/api-ref/compute/>`__
For more information on OpenStack APIs, SDKs and CLIs in general, refer to:
- `OpenStack for App Developers <https://www.openstack.org/appdev/>`__
- `Development resources for OpenStack clouds
<https://developer.openstack.org/>`__
Operators
---------
To learn how to deploy and configure OpenStack Nova, consult the documentation
available online at:
- `OpenStack Nova <https://docs.openstack.org/nova/>`__
In the unfortunate event that bugs are discovered, they should be reported to
the appropriate bug tracker. If you obtained the software from a 3rd party
operating system vendor, it is often wise to use their own bug tracker for
reporting problems. In all other cases use the master OpenStack bug tracker,
available at:
- `Bug Tracker <https://bugs.launchpad.net/nova>`__
Developers
----------
For information on how to contribute to Nova, please see the contents of the
CONTRIBUTING.rst.
Any new code must follow the development guidelines detailed in the HACKING.rst
file, and pass all unit tests.
Further developer focused documentation is available at:
- `Official Nova Documentation <https://docs.openstack.org/nova/>`__
- `Official Client Documentation
<https://docs.openstack.org/python-novaclient/>`__
Other Information
-----------------
During each `Summit`_ and `Project Team Gathering`_, we agree on what the whole
community wants to focus on for the upcoming release. The plans for nova can
be found at:
- `Nova Specs <http://specs.openstack.org/openstack/nova-specs/>`__
.. _Summit: https://www.openstack.org/summit/
.. _Project Team Gathering: https://www.openstack.org/ptg/