Open Stack

I think a option 2 is better.

Best Regards
Chaoyi Huang (joehuang)
________________________________
From: Lance Bragstad [lbragstad at gmail.com]
Sent: 25 May 2017 3:47
To: OpenStack Development Mailing List (not for usage questions); openstack-operators at lists.openstack.org
Subject: Re: [openstack-dev] [keystone][nova][cinder][glance][neutron][horizon][policy] defining admin-ness

I'd like to fill in a little more context here. I see three options with the current two proposals.

Option 1

Use a special admin project to denote elevated privileges. For those unfamiliar with the approach, it would rely on every deployment having an "admin" project defined in configuration [0].

How it works:

Role assignments on this project represent global scope which is denoted by a boolean attribute in the token response. A user with an 'admin' role assignment on this project is equivalent to the global or cloud administrator. Ideally, if a user has a 'reader' role assignment on the admin project, they could have access to list everything within the deployment, pending all the proper changes are made across the various services. The workflow requires a special project for any sort of elevated privilege.

Pros:
- Almost all the work is done to make keystone understand the admin project, there are already several patches in review to other projects to consume this
- Operators can create roles and assign them to the admin_project as needed after the upgrade to give proper global scope to their users

Cons:
- All global assignments are linked back to a single project
- Describing the flow is confusing because in order to give someone global access you have to give them a role assignment on a very specific project, which seems like an anti-pattern
- We currently don't allow some things to exist in the global sense (i.e. I can't launch instances without tenancy), the admin project could own resources
- What happens if the admin project disappears?
- Tooling or scripts will be written around the admin project, instead of treating all projects equally

Option 2

Implement global role assignments in keystone.

How it works:

Role assignments in keystone can be scoped to global context. Users can then ask for a globally scoped token

Pros:
- This approach represents a more accurate long term vision for role assignments (at least how we understand it today)
- Operators can create global roles and assign them as needed after the upgrade to give proper global scope to their users
- It's easier to explain global scope using global role assignments instead of a special project
- token.is_global = True and token.role = 'reader' is easier to understand than token.is_admin_project = True and token.role = 'reader'
- A global token can't be associated to a project, making it harder for operations that require a project to consume a global token (i.e. I shouldn't be able to launch an instance with a globally scoped token)

Cons:
- We need to start from scratch implementing global scope in keystone, steps for this are detailed in the spec

Option 3

We do option one and then follow it up with option two.

How it works:

We implement option one and continue solving the admin-ness issues in Pike by helping projects consume and enforce it. We then target the implementation of global roles for Queens.

Pros:
- If we make the interface in oslo.context for global roles consistent, then consuming projects shouldn't know the difference between using the admin_project or a global role assignment

Cons:
- It's more work and we're already strapped for resources
- We've told operators that the admin_project is a thing but after Queens they will be able to do real global role assignments, so they should now migrate *again*
- We have to support two paths for solving the same problem in keystone, more maintenance and more testing to ensure they both behave exactly the same way
  - This can get more complicated for projects dedicated to testing policy and RBAC, like Patrole


Looking for feedback here as to which one is preferred given timing and payoff, specifically from operators who would be doing the migrations to implement and maintain proper scope in their deployments.

Thanks for reading!


[0] https://github.com/openstack/keystone/blob/3d033df1c0fdc6cc9d2b02a702efca286371f2bd/etc/keystone.conf.sample#L2334-L2342

On Wed, May 24, 2017 at 10:35 AM, Lance Bragstad <lbragstad at gmail.com<mailto:lbragstad at gmail.com>> wrote:
Hey all,

To date we have two proposed solutions for tackling the admin-ness issue we have across the services. One builds on the existing scope concepts by scoping to an admin project [0]. The other introduces global role assignments [1] as a way to denote elevated privileges.

I'd like to get some feedback from operators, as well as developers from other projects, on each approach. Since work is required in keystone, it would be good to get consensus before spec freeze (June 9th). If you have specific questions on either approach, feel free to ping me or drop by the weekly policy meeting [2].

Thanks!

[0] http://adam.younglogic.com/2017/05/fixing-bug-96869/
[1] https://review.openstack.org/#/c/464763/
[2] http://eavesdrop.openstack.org/#Keystone_Policy_Meeting

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