nova/doc/source/index.rst
Eric Fried f9e13bcfed update_provider_tree devref and docstring updates
Design changes [1] from the Dublin PTG prompted some rewording of the
docstring for ComputeDriver.update_provider_tree.  And to avoid that
docstring becoming too enormous, relevant chunks of the spec [2] are
copied to a new devref document which is linked from that docstring.

[1] https://review.openstack.org/#/c/552122/
[2] http://specs.openstack.org/openstack/nova-specs/specs/rocky/approved/update-provider-tree.html

Change-Id: I06504aa2a3fe6d39ecc1e681de43be8fee9e06f6
blueprint: update-provider-tree
2018-04-05 09:09:26 -05:00

299 lines
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..
Copyright 2010-2012 United States Government as represented by the
Administrator of the National Aeronautics and Space Administration.
All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License"); you may
not use this file except in compliance with the License. You may obtain
a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations
under the License.
========================
OpenStack Compute (nova)
========================
What is nova?
=============
Nova is the OpenStack project that provides a way to provision compute
instances (aka virtual servers). Nova supports creating virtual machines,
baremetal servers (through the use of ironic), and has limited support for
system containers. Nova runs as a set of daemons on top of existing Linux
servers to provide that service.
It requires the following additional OpenStack services for basic function:
* `Keystone <https://docs.openstack.org/keystone/latest/>`__: This provides
identity and authentication for all OpenStack services.
* `Glance <https://docs.openstack.org/glance/latest/>`__: This provides the
compute image repository. All compute instances launch from glance images.
* `Neutron <https://docs.openstack.org/neutron/latest/>`__: This is
responsible for provisioning the virtual or physical networks that compute
instances connect to on boot.
It can also integrate with other services to include: persistent block
storage, encrypted disks, and baremetal compute instances.
For End Users
=============
As an end user of nova, you'll use nova to create and manage servers with
either tools or the API directly.
Tools for using Nova
--------------------
* `Horizon
<https://docs.openstack.org/horizon/latest/user/launch-instances.html>`_: The
official web ui for the OpenStack Project.
* `OpenStack Client
<https://docs.openstack.org/python-openstackclient/latest/>`_: The official
CLI for OpenStack Projects. You should use this as your CLI for most things,
it includes not just nova commands but also commands for most of the projects
in OpenStack.
* `Nova Client
<https://docs.openstack.org/python-novaclient/latest/user/shell.html>`_: For
some very advanced features (or administrative commands) of nova you may need
to use nova client. It is still supported, but the ``openstack`` cli is
recommended.
Writing to the API
------------------
All end user (and some administrative) features of nova are exposed via a REST
API, which can be used to build more complicated logic or automation with
nova. This can be consumed directly, or via various SDKs. The following
resources will help you get started with consuming the API directly.
* `Compute API Guide <https://developer.openstack.org/api-guide/compute/>`_: The
concept guide for the API. This helps lay out the concepts behind the API to
make consuming the API reference easier.
* `Compute API Reference <http://developer.openstack.org/api-ref/compute/>`_:
The complete reference for the compute API, including all methods and
request / response parameters and their meaning.
* :doc:`Compute API Microversion History </reference/api-microversion-history>`:
The compute API evolves over time through `Microversions
<https://developer.openstack.org/api-guide/compute/microversions.html>`_. This
provides the history of all those changes. Consider it a "what's new" in the
compute API.
* `Placement API Reference <https://developer.openstack.org/api-ref/placement/>`_:
The complete reference for the placement API, including all methods and
request / response parameters and their meaning.
* :ref:`Placement API Microversion History <placement-api-microversion-history>`:
The placement API evolves over time through `Microversions
<https://developer.openstack.org/api-guide/compute/microversions.html>`_. This
provides the history of all those changes. Consider it a "what's new" in the
placement API.
* :doc:`Block Device Mapping </user/block-device-mapping>`: One of the trickier
parts to understand is the Block Device Mapping parameters used to connect
specific block devices to computes. This deserves its own deep dive.
* :doc:`Configuration drive </user/config-drive>`: Provide information to the
guest instance when it is created.
Nova can be configured to emit notifications over RPC.
* :ref:`Versioned Notifications <versioned_notification_samples>`: This
provides the list of existing versioned notifications with sample payloads.
For Operators
=============
Architecture Overview
---------------------
* :doc:`Nova architecture </user/architecture>`: An overview of how all the parts in
nova fit together.
Installation
------------
.. TODO(sdague): links to all the rest of the install guide pieces.
The detailed install guide for nova. A functioning nova will also require
having installed `keystone
<https://docs.openstack.org/keystone/latest/install/>`__, `glance
<https://docs.openstack.org/glance/latest/install/>`__, and `neutron
<https://docs.openstack.org/neutron/latest/install/>`__. Please ensure that you
follow their install guides first.
.. toctree::
:maxdepth: 2
install/index
Deployment Considerations
-------------------------
There is information you might want to consider before doing your deployment,
especially if it is going to be a larger deployment. For smaller deployments
the defaults from the :doc:`install guide </install/index>` will be sufficient.
* **Compute Driver Features Supported**: While the majority of nova deployments use
libvirt/kvm, you can use nova with other compute drivers. Nova attempts to
provide a unified feature set across these, however, not all features are
implemented on all backends, and not all features are equally well tested.
* :doc:`Feature Support by Use Case </user/feature-classification>`: A view of
what features each driver supports based on what's important to some large
use cases (General Purpose Cloud, NFV Cloud, HPC Cloud).
* :doc:`Feature Support full list </user/support-matrix>`: A detailed dive through
features in each compute driver backend.
* :doc:`Cells v2 Planning </user/cellsv2-layout>`: For large deployments, Cells v2
allows sharding of your compute environment. Upfront planning is key to a
successful Cells v2 layout.
* :doc:`Placement service </user/placement>`: Overview of the placement
service, including how it fits in with the rest of nova.
* :doc:`Running nova-api on wsgi <user/wsgi>`: Considerations for using a real
WSGI container instead of the baked-in eventlet web server.
Maintenance
-----------
Once you are running nova, the following information is extremely useful.
* :doc:`Admin Guide </admin/index>`: A collection of guides for administrating
nova.
* :doc:`Flavors </user/flavors>`: What flavors are and why they are used.
* :doc:`Upgrades </user/upgrade>`: How nova is designed to be upgraded for minimal
service impact, and the order you should do them in.
* :doc:`Quotas </user/quotas>`: Managing project quotas in nova.
* :doc:`Aggregates </user/aggregates>`: Aggregates are a useful way of grouping
hosts together for scheduling purposes.
* :doc:`Filter Scheduler </user/filter-scheduler>`: How the filter scheduler is
configured, and how that will impact where compute instances land in your
environment. If you are seeing unexpected distribution of compute instances
in your hosts, you'll want to dive into this configuration.
* :doc:`Exposing custom metadata to compute instances </user/vendordata>`: How and
when you might want to extend the basic metadata exposed to compute instances
(either via metadata server or config drive) for your specific purposes.
Reference Material
------------------
* :doc:`Nova CLI Command References </cli/index>`: the complete command reference
for all the daemons and admin tools that come with nova.
* **Configuration**:
* :doc:`Configuration Guide </admin/configuration/index>`: detailed
configuration guides for various parts of you Nova system. Helpful
reference for setting up specific hypervisor backends.
* :doc:`Config Reference </configuration/config>`: a complete reference of all
configuration options available in the nova.conf file.
* :doc:`Sample Config File </configuration/sample-config>`: a sample config file
with inline documentation.
* **Policy**: nova, like most OpenStack projects, uses a policy language to
restrict permissions on REST API actions.
* :doc:`Policy Reference </configuration/policy>`: a complete reference of all
policy points in nova and what they impact.
* :doc:`Sample Policy File </configuration/sample-policy>`: a sample policy file
with inline documentation.
For Contributors
================
If you are new to Nova, this should help you start to understand what Nova
actually does, and why.
.. toctree::
:maxdepth: 1
contributor/index
There are also a number of technical references on both current and future
looking parts of our architecture. These are collected below.
.. toctree::
:maxdepth: 1
reference/index
.. # NOTE(mriedem): This is the section where we hide things that we don't
# actually want in the table of contents but sphinx build would fail if
# they aren't in the toctree somewhere. For example, we hide api/autoindex
# since that's already covered with modindex below.
.. toctree::
:hidden:
admin/index
admin/configuration/index
cli/index
configuration/index
configuration/config
configuration/sample-config
configuration/policy
configuration/sample-policy
contributor/development-environment
contributor/api
contributor/api-2
contributor/blueprints
contributor/code-review
contributor/documentation
contributor/microversions
contributor/placement.rst
contributor/policies.rst
contributor/releasenotes
contributor/testing
contributor/testing/libvirt-numa
contributor/testing/serial-console
contributor/testing/zero-downtime-upgrade
contributor/how-to-get-involved
contributor/process
contributor/project-scope
reference/api-microversion-history.rst
reference/gmr
reference/i18n
reference/live-migration
reference/notifications
reference/policy-enforcement
reference/rpc
reference/scheduling
reference/scheduler-evolution
reference/services
reference/stable-api
reference/threading
reference/update-provider-tree
reference/vm-states
user/index
user/aggregates
user/architecture
user/block-device-mapping
user/cells
user/cellsv2-layout
user/conductor
user/config-drive
user/feature-classification
user/filter-scheduler
user/flavors
user/manage-ip-addresses
user/placement
user/quotas
user/support-matrix
user/upgrade
user/user-data
user/vendordata
user/wsgi
Search
======
* :ref:`Nova document search <search>`: Search the contents of this document.
* `OpenStack wide search <https://docs.openstack.org>`_: Search the wider
set of OpenStack documentation, including forums.