DynamicPolicies
Contents
- 1 Dynamic Policies
- 1.1 Weekly Meeting
- 1.2 Background
- 1.3 Evolution
- 1.4 Roadmap
- 1.4.1 Story 1 - As a cloud admin, I want to manage Policies via API
- 1.4.2 Story 2 - As a cloud admin, I want to have services using the Policies I have defined via API
- 1.4.3 Story 3 - As a domain admin, I want to define roles that are meaningful to my business
- 1.4.4 Story 4 - As an admin, I want to define role hierarchies, allowing one to only delegate a subset of her roles
- 1.4.5 Story 5 - As a deployer, I want to have better default policies, distinguishing different admin scopes
- 1.4.6 Story 6 - As a dev, I want to split policy enforcement between Middleware and the services
- 1.5 Workflows - Liberty Scope
Dynamic Policies
Improving Access Control on OpenStack
Weekly Meeting
TBD
Background
OpenStack uses a Role-Based Access Control mechanism to manage authorization, which defines if a user is able to perform actions on resources based on the roles he has assigned on them. Resources include VMs, volumes, networks, etc and are organized into projects, which are owned by domains. Users have roles assigned on domains or projects.
Users get domain or project scoped tokens, which contains the roles the user has assigned on them, and pass this token along to services in requests to perform actions on resources. The services check the roles and the scope from the token against the rules defined for the requested action on the policy.json file to determine if the user has enough privileges.
Evolution
- How to evolve the policies management mechanism, which currently uses an out-of-band mechanism to update the policy.json files ?
- How to improve delegation mechanism, allowing users to only delegate a subset of their roles, which may be customized per domain ?
- How to provide better default policies, fixing the bug in which an admin anywhere is admin everywhere ?
Roadmap
Story 1 - As a cloud admin, I want to manage Policies via API
Depends On: None
As a cloud admin, I want to be able to create a policy and to bind it to endpoints based on their URL, which is known a priori by my CMS. Besides being able to patch, delete and show an entire policy, I want to manage rules individually.
- Specs
- Policy Management API
- TODO: Create Spec
- Associate Policy with Endpoint URL
- Policy Storage Backend
- Policy Management API
Story 2 - As a cloud admin, I want to have services using the Policies I have defined via API
Depends On: Story 1 - As a cloud admin, I want to manage Policies via API
As a cloud admin, I want my service endpoints to be using the policies I have defined and associated to them, if any. Middleware should download the latest policy from the policy management server and cache it, based on the endpoint_url in its config file. My CMS, which knows that URL a priori will be placing this value in the middleware config.
Story 3 - As a domain admin, I want to define roles that are meaningful to my business
Depends On: None
As a domain admin, who represents, for example, a customer, I want to define a set of roles that are meaningful to them. As global roles, those can be used on assignments.
Story 4 - As an admin, I want to define role hierarchies, allowing one to only delegate a subset of her roles
Depends On: None
As an admin who can define roles, I want to be able to create them hierarchically, which means that having a role that inherit from another implies on having authorization inherited.
- Specs
Story 5 - As a deployer, I want to have better default policies, distinguishing different admin scopes
Depends On: Story 4 - As a user, I want to define role hierarchies, allowing one to only delegate a subset of her roles
As a deployer, I want to have default policies defined in terms of different roles for cloud, domain and project admins. Solving the long standing but where an admin anywhere is admin everywhere. In addition, common rules should be consistent across services.
- Specs
- Improve Default Policies
- TODO: Create Spec
- Default Policy
- unified policy file
- Improve Default Policies
Story 6 - As a dev, I want to split policy enforcement between Middleware and the services
Depends On: Story 2 - As a cloud admin, I want to have services using the Policies I have defined via API
The enforcement of roles could be placed at Middleware, while the other constraints contained in a policy rule are enforced by the service.
Workflows - Liberty Scope
Workflow 1 - Initial Install
This workflow is represented by the steps 1 - 3 in the sequence diagram below, defining how the initial install of the endpoints and policy association will occur with Dynamic Policies enabled.
Workflow 2 - Customizing Policy
This workflow is represented by the steps 4 - 5 in the sequence diagram below, defining how the policies will be customized by the admin.
Workflow 3 - Updating an Existing Install
This workflow is represented by the steps 12- 13 in the sequence diagram below, defining how the Default policy for a given endpoint will be update in the server, reflecting changes in the APIs signatures. For example, when new APIs are added.
Workflow 4 - User Requests an URL
This workflow is represented by the steps 6 - 11 and 14 - 19 in the sequence diagram below, defining how the workflows above will be tied together, delivering a dynamic solution for policy customization and delivery.
Sequence Diagram
+-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+
| | | | | | | | | |
| admin | | keystone | | CMS | | nova | | user |
| | | | | | | | | |
+--------+--------+ +--------+--------+ +--------+--------+ +--------+--------+ +--------+--------+
| | | | |
| | 1 Register Nova endpoint | | |
| | | | |
| | <---------------------------+ | | |
| | | | |
| | +---------------------------> | | |
| | | | |
| | 2 Register Nova Default | | |
| | Policy and associate it | | |
| | with Nova endpoint | | |
| | | | |
| | <---------------------------+ | | |
| | | | |
| 3 Default policy for Nova is | | | |
| stored in database, | | | |
| separately from Custom policy | | | |
| which represents admin's | | | |
| changes on this Default one | | | |
| | | | |
| +---------------+ | | | |
| | | | | |
| +---------------> | | | |
| | | | |
| | +---------------------------> | | |
| | | | |
| 4 Customize policy, changing | | | |
| the rule for a given API | | | |
| | | | |
| +---------------------------> | | | |
| | | | |
| | 5 Custom policy for this Nova | | |
| | endpoint is stored into | | |
| | database | | |
| | | | |
| | +---------------+ | | |
| | | | | |
| | <---------------+ | | |
| | | | |
| <---------------------------+ | | | |
| | | | |
| | | | 6 GET /url |
| | | | |
| | | | <---------------------------+ |
| | | | |
| | 7 Middleware asks for policyssociated with No^a endpoint URL | |
| | + | |
| | <-----------------------------------------------------------+ | |
| | | | |
| 8 The policy is calculated | | | |
| based on the Default policy, | | | |
| which is overriden by what | | | |
| is in the Custom policy, | | | |
| defined by the admin | | | |
| | | | |
| +----------------+ | | | |
| | | | | |
| +----------------> | | | |
| | | | |
| | +-----------------------------------------------------------> | |
| | | | |
| | | 9 Middleware update Nova's | |
| | | policy.json on the dir | |
| | | from oslo.policy config | |
| | | | |
| | | +-------------+ | |
| | | | | |
| | | +-------------> | |
| | | | |
| | | 10 Nova enforce policy as | |
| | | today and then may execute | |
| | | the requested API | |
| | | | |
| | | +-------------+ | |
| | | | | |
| | | +-------------> | |
| | | | |
| | | | 11 200 OK |
| | | | |
| | | | +---------------------------> |
| | | | |
| | | 12 Nova deployment is updated,| |
| | | update, Defailt Policy | |
| | | which adds new APIs | |
| | | | |
| | | +---------------------------> | |
| | | | |
| | | <---------------------------+ | |
| | | | |
| | 13 Update the Nova Default | | |
| | Policy associated with | | |
| | Nova endpoint URL | | |
| | | | |
| | <---------------------------+ | | |
| | | | |
| | +---------------------------> | | |
| | | | |
| | | | 14 GET /url, triggering the |
| | | | steps 15 to 18, which are |
| | | | the same as steps 7 to 10 |
| | | | |
| | | | <---------------------------+ |
| | | | |
| | | | ... Steps 15 to 18 |
| | | | |
| | | | 19 200 OK |
| | | | |
| | | | +---------------------------> |
| | | | |
+ + + + +
