ARC Policy Framework Component Description - Honolulu-R8
- Chaker Al-Hakim
- Jorge Hernandez
- James Hahn
Page Status: Updated by PTL Jan 15, 2021
Component Status: Updated by PTL Jan 15, 2021 ; Pending PTL Updates and ArchCom Review
Last Reviewed:
Certified by:
1. High Level Component Definition and Architectural Relationships
In the Honolulu release the CLAMP component is being integrated into the Policy component as a PoC (see REQ-473: Merge CLAMP functionality into Policy Framework projectDone) . CLAMP's functional role to provision Policy stays the same, as the project and associated resources are simply moved under the policy umbrella.
2. API Definitions
2a. Exposed APIs
Interface Name | Definition | Capabilities | Version | Status | Payload Model(s) | API Spec (Swagger) |
|---|---|---|---|---|---|---|
Policy Type Design | Allows applications to create, update, delete, and query PolicyType entities so that they become available for use in ONAP by applications such as CLAMP. | 1.0.0 | production | tosca.policies.root | https://docs.onap.org/projects/onap-policy-parent/en/latest/api/api.html#api-swagger | |
Policy Design | Allows applications (such as CLAMP and Integration) to create, update, delete, and query Policy entities. | 1.0.0 | production | tosca.policies.root | https://docs.onap.org/projects/onap-policy-parent/en/latest/api/api.html#api-swagger | |
Policy Administration | Support CRUD of PDP groups and subgroups and to support the deployment and life cycles of PolicyImpl entities (TOSCA Policy and PolicyTypeImpl entities) on PDP sub groups and PDPs. | 1.0.0 | production | Embedded | https://docs.onap.org/projects/onap-policy-parent/en/latest/pap/pap.html#pap-rest-api-swagger | |
POE-4 | Data Ingress | Listen on a DMaaP topic. | production | Messages of interest are described in the policy logic DMaaP | ||
Decision Query | Policy decisions are required by ONAP components to support the policy-driven ONAP architecture. Policy Decisions are implemented using the XACML and Apex PDPs. The calling application (which may be another policy – e.g. invocation of a guard policy from PDP-D) must provide attributes in order for the PDP to return a correct decision. | NA | production | Defined by policy | https://docs.onap.org/projects/onap-policy-parent/en/latest/xacml/decision-api.html |
2b. Consumed APIs
Interface Name | Consumed by | Description | API Spec (Swagger) |
|---|---|---|---|
Policy Framework | Authentication and authorization | ||
Policy Framework Policies | Policy framework uses DMaaP for SDC subscriptions and internal communication. Policies use DMaaP as a transport for contextual information from various sources | ||
Policy Framework | Notification of CSAR; Retrieval of CSAR | ||
Policies | Enrich ingress data with topology information | ||
Policies | Trigger orchestration actions (policy driven) | ||
Policies | Trigger control actions (policy driven) | ||
Other | Policies | Trigger any interface defined in a policy, for example, trouble ticketing |
3. Component Description
The ONAP Policy Framework is a comprehensive policy design, deployment, and execution environment. The Policy Framework is the decision making component in an ONAP system. It allows you to specify, deploy, and execute the governance of the features and functions in your ONAP system, be they closed loop, orchestration, or more traditional open loop use case implementations. The Policy Framework is the component that is the source of truth for all policy decisions
Please see the TOSCA Policy Primer page for an introduction to TOSCA policy concepts. See the Policy Design and API flow page for a description of the component interactions.
TOSCA defines a PolicyType, the definition of a type of policy that can be applied to a service. It also defines a Policy, the definition of an instance of a PolicyType. In the Policy Framework, we must handle and manage these TOSCA definitions and tie them to real implementations of policies that can run on PDPs.
Each TOSCA PolicyType must have a corresponding PolicyTypeImpl in the Policy Framework. The TOSCA PolicyType definition can be used to create a TOSCA Policydefinition, either directly by the Policy Framework, by CLAMP, or by some other system. Once the Policy artifact exists, it can be used together with the PolicyTypeImpl artifact to create a PolicyImpl artifact. A PolicyImpl artifact is an executable policy implementation that can run on a PDP.
The TOSCA PolicyType artifact defines the external characteristics of the policy; defining its properties, the types of entities it acts on, and its triggers. A PolicyTypeImpl artifact is an XACML, Drools, or APEX implementation of that policy definition. PolicyType and PolicyTypeImpl artifacts may be preloaded, may be loaded manually, or may be created using the Lifecycle API. Alternatively, PolicyType definitions may be loaded over the Lifecycle API for preloaded PolicyTypeImpl artifacts. A TOSCA PolicyType artifact can be used by clients (such as CLAMP or CLI tools) to create, parse, serialize, and/or deserialize an actual Policy.
The TOSCA Policy artifact is used internally by the Policy Framework, or is input by CLAMP or other systems. This artifact specifies the values of the properties for the policy and specifies the specific entities the policy acts on. Policy Design uses the TOSCA Policy artifact and the PolicyTypeImpl artifact to create an executable PolicyImpl artifact.
Internally, Policy has three main functional areas: Policy Development; Policy Administration; Policy Decision Execution.
Policy Development abstracts persistence and supports the creation of policies/policy types.
Policy Administration also abstracts persistence (from a different user roles). It's main purposes are to ensure that policies are allocated correctly and to manage the life-cycle of policies.
Policy Decision Execution is where policy decisions are made, i.e. where the policy logic executes. Three languages are used to describe policies in ONAP: XACML; Drools; APEX. Policy designers may select the language that is most appropriate to their use case. The policies are interpreted and executed by a language specific PDP. Where necessary additional PDP may be added, thus allowing for new policy languages.
Policy Enforcement is in general not handled by the Policy Framework. Enforcement is handled by either the originator of a decision query (PDP-D does enforce guard policy decisions made in the XACML PDP), or by a reaction to a policy output (trigger).
4. Known System Limitations
https://docs.onap.org/projects/onap-policy-parent/en/latest/release-notes.html
5. System Deployment Architecture
https://docs.onap.org/projects/onap-policy-parent/en/latest/installation/installation.html
6. New Release Capabilities
The main new capability introduced in this release as a PoC is the integration of the CLAMP component under the policy umbrella (see REQ-473: Merge CLAMP functionality into Policy Framework projectDone). The software is being moved under the policy/clamp repository (https://git.onap.org/policy/clamp). The OOM helm charts are also moving as a subcomponent of policy (https://git.onap.org/oom/tree/kubernetes/policy/components).
And additional PoC experiments with defining Control Loops fully in Tosca. This is covered by REQ-478: PoC - TOSCA Defined Control Loop on Honolulu ReleaseIn Progress.
As outlined in the architecture review page (Policy Honolulu-R8 Architecture Review) the only new use case that may be supported as a stretch goal is the 5G one (REQ-429: Use Case for ONAP-based SON for 5G networksDone). Existing use cases will be supported (no change).
Conformance with ONAP wide requirements (REQ-441: LOGS MANAGEMENT - PHASE 1: COMMON PLACE FOR DATATo Do,REQ-437: COMPLETION OF PYTHON LANGUAGE UPDATE (v2.7 → v3.x)In Progress, REQ-398: Deploy on demand ONAP through CI per use caseDone, REQ-396: Clearly split ONAP code and use case code To Do, and REQ-439: CONTINUATION OF PACKAGES UPGRADES IN DIRECT DEPENDENCIESIn Progress (there are some risks, see Honolulu Risks page)) are already or will be supported.
Additional enhancements to the Policy components will be introduced in this release that have no external impact. These include but are not limited to:
Stateless PAP (Keep no state in PAP runtime container, so state retrieval would be from database).
Interoperability of Native and non-native policies in the Drools PDP.
Healthcheck status improvements as well as statistics reporting.
7. References
Honolulu architecture description https://docs.onap.org/projects/onap-policy-parent/en/latest/architecture/architecture.html
Policy Framework API's - https://docs.onap.org/projects/onap-policy-parent/en/latest/offeredapis.html