wu.chunyang 8eb9a90724 Add release note link in README

Change-Id: I6058fa986729fc95d070940c6f00f33065477ced

2018-06-29 08:53:59 +00:00

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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 clouds no matter what crazy choices the deployer has made in an attempt to be more hipster than their self-entitled narcissist peers, then the Cloud Abstraction layer is for you.

A Brief History

openstacksdk started its life as three different libraries: shade, os-client-config and python-openstacksdk.

shade started its life as some code inside of OpenStack Infra's nodepool project, and as some code inside of the Ansible OpenStack Modules. Ansible had a bunch of different OpenStack related modules, and there was a ton of duplicated code. Eventually, between refactoring that duplication into an internal library, and adding the logic and features that the OpenStack Infra team had developed to run client applications at scale, it turned out that we'd written nine-tenths of what we'd need to have a standalone library.

Because of its background from nodepool, shade contained abstractions to work around deployment differences and is resource oriented rather than service oriented. This allows a user to think about Security Groups without having to know whether Security Groups are provided by Nova or Neutron on a given cloud. On the other hand, as an interface that provides an abstraction, it deviates from the published OpenStack REST API and adds its own opinions, which may not get in the way of more advanced users with specific needs.

os-client-config was a library for collecting client configuration for using an OpenStack cloud in a consistent and comprehensive manner, which introduced the clouds.yaml file for expressing named cloud configurations.

python-openstacksdk was a library that exposed the OpenStack APIs to developers in a consistent and predictable manner.

After a while it became clear that there was value in both the high-level layer that contains additional business logic and the lower-level SDK that exposes services and their resources faithfully and consistently as Python objects.

Even with both of those layers, it is still beneficial at times to be able to make direct REST calls and to do so with the same properly configured Session from python-requests.

This led to the merge of the three projects.

The original contents of the shade library have been moved into openstack.cloud and os-client-config has been moved in to openstack.config. Future releases of shade will provide a thin compatibility layer that subclasses the objects from openstack.cloud and provides different argument defaults where needed for compatibility. Similarly future releases of os-client-config will provide a compatibility layer shim around openstack.config.

openstack

List servers using objects configured with the clouds.yaml file:

import openstack

# Initialize and turn on debug logging
openstack.enable_logging(debug=True)

# Initialize cloud
conn = openstack.connect(cloud='mordred')

for server in conn.compute.servers():
    print(server.to_dict())

openstack.config

openstack.config will find cloud configuration for as few as 1 clouds 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

Sometimes an example is nice.

Create a clouds.yaml file:

clouds:
 mordred:
   region_name: Dallas
   auth:
     username: 'mordred'
     password: XXXXXXX
     project_name: 'shade'
     auth_url: 'https://identity.example.com'

Please note: openstack.config will look for a file called clouds.yaml in the following locations:

Current Directory
~/.config/openstack
/etc/openstack

More information at https://docs.openstack.org/openstacksdk/latest/user/config/configuration.html

openstack.cloud

Create a server using objects configured with the clouds.yaml file:

import openstack.cloud

# Initialize and turn on debug logging
openstack.enable_logging(debug=True)

# Initialize connection
# Cloud configs are read with openstack.config
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 for it.
conn.create_server(
    'my-server', image=image, flavor=flavor, wait=True, auto_ip=True)

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