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Introduction
This page summarizes issues (documented in child pages) and the decisions/direction taken.
Decisions/direction is discussed in the child pages, and ratified during the weekly meeting.
Assumptions
| # | Assumption | Reasoning/Justification |
|---|---|---|
| 1 | The CPS stand-alone access interface technology will be REST | This is common practice in ONAP. There is a drive to harmonize publication and documentation of component interfaces. |
| 2 | The CPS internal core implementation will be Java | Alternative language bindings will be possible (explicitly enabled by the architecture). The level of resources available indicates that a single implementation should be pursued first. Where other language run-times need access to data they may use the REST data access interfaces. |
| 3 | The native model language of the CPS will be YANG | Industry momentum towards YANG IETF RFC, widely supported Superset of most language capabilities |
| 4 | The PoC will use PostgreSQL as the DBMS | None, other than one is required |
Topic Areas
Issues & Decisions
(closed issue will be marked in green)
| # | Topic Area | Priority | Issue slogan/link | Brief description | Ready to discuss | Decision |
|---|---|---|---|---|---|---|
| 1 | 4 | AGREED | Integration pattern for current, historical, temporal, timeseries, etc. | The CPS project proposal covers multiple types of storage. How will it integrate several DBMS technologies to support these different needs? | -- | Option C. Loose coupling. The focus of the PoC will be on current storage and model driven notifications to drive data towards other data stores. |
| 2 | 5 | AGREED | Backward Compatibility with Config DB | The current API is a basic hard coded REST interface with specific methods supporting 2 object types and a few operations. Although extensible it will be hard to keep the new proposed interface backward compatible with the original API. | -- | No Compatibility. Either a adapter will be provided later of some resource will be set reserved to migrate the existing client to the new service when available. |
| 3 | 4,5 | AGREED | Interface style | The access interface needs to suit the users of the data. It must also acknowledge the underlying data structure. There are two main options: Providing behavior interfaces on a logical representation of the data; Providing behavior interfaces on the CPS and explicitly providing reference to the data | -- | Option B, Access methods on the CPS; Data object provides context to those methods. |
| 4 | 4,5 | AGREED | Data Representation | The data that is read from and written to the CPS must comply with a known format. This is relevant to both Java and REST interfaces. The choices here are to provide generic objects/documents, or highly typed (using model info). | -- | Option A. Data will be represented as documents (REST) and or generic objects (glorified maps in Java) |
| 5 | 1,3 | AGREED | Flow of models into the system | The CPS will be model driven, which means that new models can be added to the CPS. How will models be introduced to the CPS from other components in the ONAP system or the network? | -- | There will be a single way to add a YANG model to CPS. This is done through the CPS model life-cycle management interface. There are three ways in which the ONAP platform can add models. See details in Flow of models into the system |
| 6 | 1,3 | MEDIUM | Upgrade of models | As the network functions evolve, new versions of models will be introduced that will replace existing models for new versions of the NF. These new versions will need to co-exist alongside existing versions, such that different NF versions can be modelled using the appropriate model version Discuss with ChrisC (SDC) | No | |
| 7 | 1 | LOW | Specifiy and configure CPS behavior | The behavior of the CPS needs to be driven by a model. The native model language of CPS is YANG. There are several mechanisms available to achieve this need. One needs to be selected | No | |
| 8 | 1 | AGREED | Existing Yang Parser | Is there an existing Yang Parser in ONAP an/or OpenDayLight that can be used for C&PS: yes; ODL's Yang Tools. This is already widely used in OMAP Java Projects (for more details follow link in prev. column) PYang - a standard python tool for processing Yang model; benefit over ODL; conver to XML to perform own processing. Yang is a simple tree data structure. difficulty is extending/augmentation. PYang will come up with representation of data. Locked into Java vs a table. A Yang model can be served in V1/V2. Version management of Yang models. Augmentation to deal with modification of V1 of a model; upgrade from V1 > V2. maintaining schemas (Yang model) can ingest data in either V1 or V2 & serve it in V1/V2. | Yes | For the Java-based service ODL's Yang Tools will be used. For specific use-cases it might be more suitable yo use Python and PYang e.g. Model Visualization. |
| 9 | N/A | AGREED | Location of PoC Code | Dan Timony suggested to use and existing CCSDK repo, he mentioned ccsdk/features. As long as the PoC remains completely independent and doesn't affect delivery of existing artifacts in the same repo. | -- | ccsdk/features, see https://gerrit.onap.org/r/c/ccsdk/features/+/110385 (awaiting approval) |
| 10 | N/A | AGREED | Common information model, Data lake and Access control | How will the CPS help with managing coupling between ONAP components that make use of data lake and common information model | -- | We will start with Architectural Approach A in the PoC with the aim of fully supporting Architectural Approach C. I.e. access to the data lake will be conditional on permission granted by the data owner. In the PoC we will not implement the permission granting mechanism |
| 11 | 4,5 | AGREED | Transactional behavior | It needs to be clear to users the level of atomic operations supported by the CPS. Transactions are performed sequentially and atomically (one at a time). As an external user you have a Java interface (with a dedicated mSvc) & REST interface. It is up to the user of C&PS to specify the order of changes in their input document. | -- | The CPS will not use an external transaction manager. Where the underlying DBMS provides transactions, these will be exposed by the SPI and used by the CPS core library. The CPS core library will expose a simple session concept to co-deployed modules. This will enable fine grained control of the order of changes. This will help ensure that complex validation (e.g. WHEN clause) succeeds. For REST users, the session concept will not be exposed. Where documents representing several operations are input, the CPS will follow the order of the input document, and fail fast. Any failures will be abandoned (if the underlying DBMS supports transactions) and a failure response will be returned to the REST user. (Rest of the Page is accepted) |
| 12 | 5 | MEDIUM | 5G Service Modeling Use Case and interactions with C&PS. (1) Registration system - Creating a system for registration discovery & management mechanism to allow for coordination and inter-operation of micro-services who want access to common data. Models are also stored in the registry. | No | The scope of the CPS will include a 'Registry Service' More good discussion . Needs separate meeting to clarify | |
| 13 | 5 | AGREED | CCSDK-2870 DP: CPS REST API Documentation | Discuss Rest API | Yes | |
| 14 | MEDIUM | CPS & DCAE DES concept sharing | Discussion about usage of DCAE Data Exposure Service (DES) concept | No | ||
| 15 | 5 | AGREED | Discuss the Java API and SPI wiki. Both pages include javadoc and a link to the gerrit repo. | Yes | ||
| 16 | 1,5 | AGREED | Yang modules to XPath format adaptation | Discuss the XPath adaptation to address data fragments in a context of Yang Modules revisions variety | For now there is no need to store full module identifier in the xpath field. The namespace, revision, parent module context will be taken into account using references through dedicated fields (module_id, parent_id). Limitation determined: only keyed collections are supported. The attribute order for composite keys to be handled as dedicated task. | |
| 17 | 1,5 | AGREED | Operating with Module Sets (groups of modules) | The module-set to module relationship, module-set immutability, taking into account cross-impact of modules on module-set persistence | Module-set is immutable collection of modules. None of modules can be added or removed independently, only as part of module-set insert or delete. Also module-set itself does not assume updates for now. The module-set uniqueness within a dataspace to be identified by string identifier now, also by content later The modules are stored as source definition, no processing on module entity persistence. On data validation it's expected the schema context (representing effective models) to be compiled with taking into account all the modules from the module-set. The persistence of pre-compiled context (as module-set content) or caching it or other performance optimizations to be discussed later. | |
| 18 | AGREED | ModuleSet content persistence proposal | The moduleset persistence approach, artifact/entity naming | Module Set sources (yang files) to be stored on a unique content basis. To rename: | ||
| 19 | MEDIUM | CPS Logging Config | Discuss issues/decisions in relation to logging in CPS. |