openstacksdk/README.rst
Stephen Finucane 85a2f10159 Improve README to provide example of Resource usage
Provide a simple "hello world" example that includes details on using
the 'Resource' subclasses. References to 'clouds.yaml' are also moved
earlier in the doc since this is a pretty essential part of using
openstacksdk.

Change-Id: I6e7e6b5d9f54ec15b8e886b78649b50e02d38fc4
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
2021-03-24 13:46:03 +00:00

157 lines
5.2 KiB
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============
openstacksdk
============
openstacksdk is a client library for building applications to work
with OpenStack clouds. The project aims to provide a consistent and
complete set of interactions with OpenStack's many services, along with
complete documentation, examples, and tools.
It also contains an abstraction interface layer. Clouds can do many things, but
there are probably only about 10 of them that most people care about with any
regularity. If you want to do complicated things, the per-service oriented
portions of the SDK are for you. However, if what you want is to be able to
write an application that talks to any OpenStack cloud regardless of
configuration, then the Cloud Abstraction layer is for you.
More information about the history of openstacksdk can be found at
https://docs.openstack.org/openstacksdk/latest/contributor/history.html
Getting started
---------------
openstacksdk aims to talk to any OpenStack cloud. To do this, it requires a
configuration file. openstacksdk favours ``clouds.yaml`` files, but can also
use environment variables. The ``clouds.yaml`` file should be provided by your
cloud provider or deployment tooling. An example:
.. code-block:: yaml
clouds:
mordred:
region_name: Dallas
auth:
username: 'mordred'
password: XXXXXXX
project_name: 'demo'
auth_url: 'https://identity.example.com'
openstacksdk will look for ``clouds.yaml`` files in the following locations:
* ``.`` (the current directory)
* ``$HOME/.config/openstack``
* ``/etc/openstack``
openstacksdk consists of three layers. Most users will make use of the *proxy*
layer. Using the above ``clouds.yaml``, consider listing servers:
.. code-block:: python
import openstack
# Initialize and turn on debug logging
openstack.enable_logging(debug=True)
# Initialize connection
conn = openstack.connect(cloud='mordred')
# List the servers
for server in conn.compute.servers():
print(server.to_dict())
openstacksdk also contains a higher-level *cloud* layer based on logical
operations:
.. code-block:: python
import openstack
# Initialize and turn on debug logging
openstack.enable_logging(debug=True)
# Initialize connection
conn = openstack.connect(cloud='mordred')
# List the servers
for server in conn.list_servers():
print(server.to_dict())
The benefit of this layer is mostly seen in more complicated operations that
take multiple steps and where the steps vary across providers. For example:
.. code-block:: python
import openstack
# Initialize and turn on debug logging
openstack.enable_logging(debug=True)
# Initialize connection
conn = openstack.connect(cloud='mordred')
# Upload an image to the cloud
image = conn.create_image(
'ubuntu-trusty', filename='ubuntu-trusty.qcow2', wait=True)
# Find a flavor with at least 512M of RAM
flavor = conn.get_flavor_by_ram(512)
# Boot a server, wait for it to boot, and then do whatever is needed
# to get a public IP address for it.
conn.create_server(
'my-server', image=image, flavor=flavor, wait=True, auto_ip=True)
Finally, there is the low-level *resource* layer. This provides support for the
basic CRUD operations supported by REST APIs and is the base building block for
the other layers. You typically will not need to use this directly:
.. code-block:: python
import openstack
import openstack.config.loader
import openstack.compute.v2.server
# Initialize and turn on debug logging
openstack.enable_logging(debug=True)
# Initialize connection
conn = openstack.connect(cloud='mordred')
# List the servers
for server in openstack.compute.v2.server.Server.list(session=conn.compute):
print(server.to_dict())
.. _openstack.config:
Configuration
-------------
openstacksdk uses the ``openstack.config`` module to parse configuration.
``openstack.config`` will find cloud configuration for as few as one cloud and
as many as you want to put in a config file. It will read environment variables
and config files, and it also contains some vendor specific default values so
that you don't have to know extra info to use OpenStack
* If you have a config file, you will get the clouds listed in it
* If you have environment variables, you will get a cloud named `envvars`
* If you have neither, you will get a cloud named `defaults` with base defaults
You can view the configuration identified by openstacksdk in your current
environment by running ``openstack.config.loader``. For example:
.. code-block:: bash
$ python -m openstack.config.loader
More information at https://docs.openstack.org/openstacksdk/latest/user/config/configuration.html
Links
-----
* `Issue Tracker <https://storyboard.openstack.org/#!/project/openstack/openstacksdk>`_
* `Code Review <https://review.opendev.org/#/q/status:open+project:openstack/openstacksdk,n,z>`_
* `Documentation <https://docs.openstack.org/openstacksdk/latest/>`_
* `PyPI <https://pypi.org/project/openstacksdk/>`_
* `Mailing list <http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-discuss>`_
* `Release Notes <https://docs.openstack.org/releasenotes/openstacksdk>`_