clouds.yaml support in clients

clouds.yaml is a config file for the facilitation of consuming multiple OpenStack clouds in a reasonable way. It is processed by the os-client-config library, and is currently supported by python-openstackclient, shade, nodepool and Ansible 2.0.

It should be supported across the board in our client utilities.

Problem description

One of the goals of our efforts in OpenStack is interoperability between clouds. Although there are several reasons that this is important, one of them is to allow consumers to spread their workloads across multiple clouds.

Once a user has more than one cloud, dealing with credentials for the tasks of selecting a specific cloud to operate on, or of performing actions across all available clouds, becomes important.

Because the only auth information mechanism the OpenStack project has provided so far, openrc, is targetted towards a single cloud, projects have have attempted to deal with the problem in a myriad of different ways that do not carry over to each other.

Although python-openstackclient supports clouds.yaml cloud definitions, there are still some functions not yet exposed in python-openstackclient and cloud users sometimes have to fall back to the legacy client utilities. That means that even though python-openstackclient allows the user to manage their clouds simply, the problem of dealing with piles of openrc files remains, making it a net loss complexity-wise.

Proposed change

Each of the python client utilities that exist should use os-client-config to process their input parameters. New projects that do not yet have a CLI utility should use python-openstackclient instead, and should not write new CLI utilities.

An example of migrating an existing utility to os-client-config can be seen in https://review.openstack.org/#/c/236325/ which adds the support to python-neutronclient. Since all of those need to migrate to keystoneauth1 anyway, and since os-client-config is well integrated with keystoneauth1 it makes sense to do it as a single change.

This change will also add OS_CLOUD and –os-cloud as options supported everywhere for selecting a named cloud from a collection of configured cloud configurations.

Horizon should add a ‘Download clouds.yaml’ link where the ‘Download openrc’ link is.

Reach out to the ecosystem of client utilities and libraries to suggest adding support for consuming clouds.yaml files. gophercloud https://github.com/rackspace/gophercloud/issues/487 has been contacted already, but at least libcloud, fog, jclouds - or any other framework that is in the Getting Started guide should at least be contacted about adding support.

It should be pointed out that os-client-config does not require the use of or existence of clouds.yaml and the traditional openrc environment variables will continue to work as always.

http://inaugust.com/posts/multi-cloud-with-python-openstackclient.html is a walkthrough on what life looks like in a world of os-client-config and python-openstackclient.

Alternatives

Using envdir has been suggested and is a good fit for direct user consumption. However, some calling environments like tox and ansible make communicating information from the calling context to the execution context via environment variables clunkier than one would like. python-neutronclient for instance has a functional-creds.conf that it writes out to avoid the problems with environment variables and tox.

Just focus on python-openstackclient. While this is a wonderful future, it’s still the future. Adding clouds.yaml support to the existing clients gets us a stronger bridge to the future state of everyone using python-openstackclient for everything.

Use oslo.config as the basis of credentials configuration instead of yaml. This was originally considered when os-client-config was being written, but due to the advent of keystone auth plugins, it becomes important for some use cases to have nested data structures, which is not particularly clean to express in ini format.

Implementation

Assignee(s)

Primary assignee:
mordred

mordred is happy to do all of the work - but is also not territorial and if elements of the work magically get done by happy friends, the world would be a lovely place.

Work Items

Not exhaustive, but should be close. Many projects provide openstackclient extensions rather than their own client, so are covered already.

  • Add support to python-barbicanclient
  • Add support to python-ceilometerclient
  • Add support to python-cinderclient
  • Add support to python-designateclient
  • Add support to python-glanceclient
  • Add support to python-heatclient
  • Add support to python-ironicclient
  • Add support to python-keystoneclient
  • Add support to python-magnumclient
  • Add support to python-manilaclient
  • Add support to python-neutronclient
  • Add support to python-novaclient
  • Add support to python-saharaclient
  • Add support to python-swiftclient
  • Add download link to horizon

Dependencies

None

History

Revisions
Release Name Description
Mitaka Introduced

Note

This work is licensed under a Creative Commons Attribution 3.0 Unported License. http://creativecommons.org/licenses/by/3.0/legalcode

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