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.dubre...@gmail.com <mailto:gil.dubre...@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.
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?
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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