Background:
In R2, SO is the only consumer of OOF. When it sends out homing requests, OOF will respond with the most appropriate flavors accordingly.
Taking the VNF vG inside vCPE use case as an example:
Inside the vG VNF Resources, there's one VFC(or VNFC) called vG. And for the vG VFC, there's a vG VF Module which is somewhat a deployment unit in HEAT for that VFC. And the vG VF Module can be used to deploy multiple vG VFCs in one time.
When SO sends out a request containing the vG VNF information to OOF, OOF will respond with flavor of each VFC inside vG VNF Resources. And let SO do the extra steps of deployments.
Now in R3, OOF is going to support both two orchestrators (SO and VF-C) in ONAP in Casablanca Release. As As they are using two different Models(HEAT and Pure Tosca), the expression differs from each other. In order to make OOF capable to process these two different requests within the same engine, we'd like to combine these expressions together inside a single Policy.
Sample Policy Schema
Thus a data block called 'directives' and some attributes(type and vduName) will be added inside policy to transfer the information that needed by OOF. And it also contains two parts, one includes the flavor at a VNFC level, the other contains the specific information needed by such hpa-feature.
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