Open Stack

On Tue, May 5, 2015 at 11:36 AM, Rich Megginson <rmeggins at redhat.com> wrote:

>  On 05/05/2015 12:20 PM, Colleen Murphy wrote:
>
> I'm cross-posting to the dev list since this conversation should be
> happening there and is related to another thread there.
>
>
> Ok.  I'm not replying puppet-openstack.
>
>  I'm going to top-post a summary and then respond inline.
>
>  The summary so far is that puppet-openstacklib provides a way to pass in
> credentials to an API-driven puppet type via an auth parameter[1] included
> in the types like so[2]. The benefit of this is that a user could create
> additional API resources, such as keystone_user, by passing in credentials
> directly to the type (presumably via hiera) without having to read
> credentials out of keystone.conf. The desire for something like this was
> outlined in the initial aviator blueprint[3] (the openstackclient
> blueprint[4] changed some of the design parameters, but not that one).
>
>  self.instances and self.prefetch are class methods provided by puppet
> that types and providers typically override. These methods are unable to
> read type parameters, as far as I can tell, because they do not have a
> specific instance from which to look up those parameters. In our
> implementation, self.instances exists so that the command `puppet resource
> keystone_user` works and returns a list of keystone_users, and we don't use
> self.prefetch. So, the way the providers are intended to work right now is:
> when creating a single resource, to run a custom 'instances' object method
> to list resources and check for existence, which can use username/password
> credentials passed in to the resource OR use username/password credentials
> set as environment variables OR fall back to reading admin_token
> credentials from keystone.conf, as it always did; when run in `puppet
> resource` mode, it runs self.instances which can only use credentials set
> as environment variables or read credentials from keystone.conf since it
> has no way to accept an auth parameter.
>
>  There are a couple of problems with this approach, one outlined by
> Gilles below and another that I'm just noticing.
>
> On Mon, May 4, 2015 at 8:34 PM, Gilles Dubreuil <gil.dubreuil at gmail.com>
> wrote:
>
>> Hi Colleen,
>>
>> The issue is about having to deal with 2 different code paths because
>> authentication could be optionally passed to a resource instance where it
>> can't when dealing with self.instances.
>> Its creates many complications down the road.
>> I initially expressed that from a technical OO point of view, although as
>> you said it doesn't really matter.
>> So, let's look at those examples:
>> https://review.openstack.org/#/c/178385/3/lib/puppet/provider/keystone.rb
>>
>> https://review.openstack.org/#/c/178456/6/lib/puppet/provider/keystone_endpoint/openstack.rb
>>
>> Providers should not have to go through that.
>>
> That is indeed pretty awful, I had no idea this would get so complicated
> when I initially wrote this.
>
>
> I don't believe the final implementation will be that bad.  I don't think
> we have to support v2 any more.  We will just assume we always have enough
> information to use v3 auth and v3 api.  Based on our discussions here and
> on IRC, this is possible and is desireable.
>
Okay.

>
>
>  I'm also noticing what looks like a major flaw in that the object
> instances method seems almost entirely useless. A resource looks up the
> full list of resources but only ever stores one[5]. So the goal of
> replacing self.prefetch with an object method that had access to the auth
> params is just not accomplished at all.
>
>>
>> This is why I think avoiding passing authentication details in some case
>> (instance) should be avoided.
>> The authentication is provided by another layer, basically the
>> environment, whether that comes from.
>>
> Given the added complexity that you pointed out and the fact that the
> motivation behind some of that complexity is moot, I'm inclined to agree.
> We could avoid this complexity and be be able to take advantage of
> self.prefetch (which should speed up performance) if we did away with the
> auth parameter and the methods needed to accommodate that parameter.
>
>  The modules do not use that auth parameter themselves, it's intended as
> an add-on if users wanted to include extra keystone_user, etc, resources in
> their profiles and didn't want to worry about running it on the keystone
> node. I rather doubt anyone is actually using that yet, and I'm curious if
> anyone has a desire to keep it around.
>
>
> I cannot figure out a use case for having per-resource authentication
> parameters.  It seems that the likely use case would be for per-run auth
> parameters, set via env. or config file.
>
> However, in openstack.rb self.request - what if self.request were changed
> to do the same thing as the instance request method?
>
self.request and request are basically identical except one is from the
instance scope and one is from the class scope, so request would be removed
if we abandoned the auth parameter.

>
>
>
>  So if the providers could both read a config file (keystone.conf,
> glance-api.conf, etc) and read environment variables for authentication,
> would that be desireable?
>
>
> Yes.
>
>
>  The auth param can accept a path to an openrc file, but if we just
> assumed a certain path we could have the provider check that for
> credentials as well. puppet-openstack_extras happens to place it in
> /root/openrc[6].
>
>
> Yes.  It would be nice to have a fallback path if there is no
> resource[:auth]['openrc']
>
>
>> Don't get me wrong the new openstacklib is great but the authentication
>> being different between class and instances.
>> Again, the authentication should be the same for the a whole provider,
>> unconditionally.
>> Otherwise, sure it works, I don't know how to put it, honestly, it breaks
>> the spirit of the providers.
>>
>> Richm, imcsk8, and I have discussed around that issue (keystone v2/v3
>> support) and decided to talk to you before pushing anything, but we do
>> think this boulder to be removed.
>> By doing so we'll be able to move faster.
>>
> Thanks for doing so. I'm glad we could have this discussion.
>
>>
>> I'm in time zone UTC+10 - Will try tomorrow morning for me, arvo for you.
>>
>> Gilles
>>   --
>>
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>>
>
>  Colleen
>
>  [1]
> http://git.openstack.org/cgit/stackforge/puppet-openstacklib/tree/lib/puppet/util/openstack.rb
> [2]
> http://git.openstack.org/cgit/stackforge/puppet-keystone/tree/lib/puppet/type/keystone_user.rb#n85
> [3]
> https://blueprints.launchpad.net/puppet-openstacklib/+spec/use-aviator-in-module-resources
> [4]
> https://blueprints.launchpad.net/puppet-openstacklib/+spec/use-openstackclient-in-module-resources
> [5]
> http://git.openstack.org/cgit/stackforge/puppet-keystone/tree/lib/puppet/provider/keystone_user/openstack.rb#n212
> [6]
> http://git.openstack.org/cgit/stackforge/puppet-openstack_extras/tree/manifests/auth_file.pp#n86
>
>
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