Open Stack

On 09/11/2015 01:03 AM, Gilles Dubreuil wrote:
> Hi,
>
> Today in the #openstack-puppet channel a discussion about the pro and
> cons of using domain parameter for Keystone V3 has been left opened.
>
> The context
> ------------
> Domain names are needed in Openstack Keystone V3 for identifying users
> or groups (of users) within different projects (tenant).
> Users and groups are uniquely identified within a domain (or a realm as
> opposed to project domains).
> Then projects have their own domain so users or groups can be assigned
> to them through roles.
>
> In Kilo, Keystone V3 have been introduced as an experimental feature.
> Puppet providers such as keystone_tenant, keystone_user,
> keystone_role_user have been adapted to support it.
> Also new ones have appeared (keystone_domain) or are their way
> (keystone_group, keystone_trust).
> And to be backward compatible with V2, the default domain is used when
> no domain is provided.
>
> In existing providers such as keystone_tenant, the domain can be either
> part of the name or provided as a parameter:
>
> A. The 'composite namevar' approach:
>
>     keystone_tenant {'projectX::domainY': ... }
>   B. The 'meaningless name' approach:
>
>    keystone_tenant {'myproject': name='projectX', domain=>'domainY', ...}
>
> Notes:
>   - Actually using both combined should work too with the domain
> supposedly overriding the name part of the domain.
>   - Please look at [1] this for some background between the two approaches:
>
> The question
> -------------
> Decide between the two approaches, the one we would like to retain for
> puppet-keystone.
>
> Why it matters?
> ---------------
> 1. Domain names are mandatory in every user, group or project. Besides
> the backward compatibility period mentioned earlier, where no domain
> means using the default one.
> 2. Long term impact
> 3. Both approaches are not completely equivalent which different
> consequences on the future usage.
> 4. Being consistent
> 5. Therefore the community to decide
>
> The two approaches are not technically equivalent and it also depends
> what a user might expect from a resource title.
> See some of the examples below.
>
> Because OpenStack DB tables have IDs to uniquely identify objects, it
> can have several objects of a same family with the same name.
> This has made things difficult for Puppet resources to guarantee
> idem-potency of having unique resources.
> In the context of Keystone V3 domain, hopefully this is not the case for
> the users, groups or projects but unfortunately this is still the case
> for trusts.
>
> Pros/Cons
> ----------
> A.
>    Pros
>      - Easier names
>    Cons
>      - Titles have no meaning!
>      - Cases where 2 or more resources could exists
>      - More difficult to debug
>      - Titles mismatch when listing the resources (self.instances)
>
> B.
>    Pros
>      - Unique titles guaranteed
>      - No ambiguity between resource found and their title
>    Cons
>      - More complicated titles
>
> Examples
> ----------
> = Meaningless name example 1=
> Puppet run:
>    keystone_tenant {'myproject': name='project_A', domain=>'domain_1', ...}
>
> Second run:
>    keystone_tenant {'myproject': name='project_A', domain=>'domain_2', ...}
>
> Result/Listing:
>
>    keystone_tenant { 'project_A::domain_1':
>      ensure  => 'present',
>      domain  => 'domain_1',
>      enabled => 'true',
>      id      => '7f0a2b670f48437ba1204b17b7e3e9e9',
>    }
>     keystone_tenant { 'project_A::domain_2':
>      ensure  => 'present',
>      domain  => 'domain_2',
>      enabled => 'true',
>      id      => '4b8255591949484781da5d86f2c47be7',
>    }
>
> = Composite name example 1  =
> Puppet run:
>    keystone_tenant {'project_A::domain_1', ...}
>
> Second run:
>    keystone_tenant {'project_A::domain_2', ...}
>
> # Result/Listing
>    keystone_tenant { 'project_A::domain_1':
>      ensure  => 'present',
>      domain  => 'domain_1',
>      enabled => 'true',
>      id      => '7f0a2b670f48437ba1204b17b7e3e9e9',
>     }
>    keystone_tenant { 'project_A::domain_2':
>      ensure  => 'present',
>      domain  => 'domain_2',
>      enabled => 'true',
>      id      => '4b8255591949484781da5d86f2c47be7',
>     }
>
> = Meaningless name example 2  =
> Puppet run:
>    keystone_tenant {'myproject1': name='project_A', domain=>'domain_1', ...}
>    keystone_tenant {'myproject2': name='project_A', domain=>'domain_1',
> description=>'blah'...}
>
> Result: project_A in domain_1 has a description
>
> = Composite name example 2  =
> Puppet run:
>    keystone_tenant {'project_A::domain_1', ...}
>    keystone_tenant {'project_A::domain_1', description => 'blah', ...}
>
> Result: Error because the resource must be unique within a catalog
>
> My vote
> --------
> I would love to have the approach A for easier name.
> But I've seen the challenge of maintaining the providers behind the
> curtains and the confusion it creates with name/titles and when not sure
> about the domain we're dealing with.
> Also I believe that supporting self.instances consistently with
> meaningful name is saner.
> Therefore I vote B

+1

Although, in my limited testing, I have not been able to get this to 
work with Puppet 3.8.  I've been following the link below to create a 
keystone_tenant provider with multiple namevars (name and domain).  I 
still can't figure out how to get puppet to think that

   keystone_tenant {'myproject1': name='project_A', domain=>'domain_1', ...}
   keystone_tenant {'myproject2': name='project_A', domain=>'domain_2', ...}

are different, distinct, unique projects.

I think it's going to take someone with a _lot_ of Puppet/Ruby 
experience and a lot of time to develop something that will work for a 
wide variety of scenarios.

>
> Finally
> ------
> Thanks for reading that far!
> To choose, please provide feedback with more pros/cons, examples and
> your vote.
>
> Thanks,
> Gilles
>
>
> PS:
> [1] https://groups.google.com/forum/#!topic/puppet-dev/CVYwvHnPSMc