UNIFY virtualizer library

Introduction

This module is a Virtualizer data model implementation example library in Python for the EU-FP7-UNIFY project.

The Virtualizer YANG model was presented in draft-unify-nfvrg-recursive-programming.

The main goal of the library was to provide a common interface between components from various partners, by realizing the Sl-Or UNIFY reference point according to the Virtualizer YANG model. Further expectations on the library were:

• Realize the elements of the Yang model by Python Objects
• Parse an entire Virtualizer instance from XML
• Dump an entire Virtualizer instance to XML
• Support main Netconf abstractions
• Support workflows, like: get config, edit config, diff config
• Support working with full configurations as well as partial updates to existing configurations
• Support easy access to components of an object (e.g. flow entries of a flow table)
• Support walking in the structure (e.g. from a port of a flow entry to the NF to which the port belongs to)

The library consists of two main files:

• virtualizer3.py: contains the Virtualizer object structure. This is autogenerated from the virtualizer3.yang module.
• baseclasses.py: contains the common components for the library, like the base Yang class for generic parsing, comparison, etc.

Installing

To install Virtualizer for development purposes, run:

$ sudo python setup.py develop

This will not actually install all the files in your system, but just link them to your development environment, simplifying the code/deploy/test cycle.

In order to install Virtualizer for demo/production purposes in a system-wide setup, run:

$ sudo python setup.py install

Alternatively, append the --user flag to install it for just your user, without root privileges being necessary.

Usage examples

• A = Virtualizer(): init an empty virtualizer object
• B = Virtualizer.parse(xml): to parse an instance from an XML input (file or string)
• B.xml(): to dump an instance to an XML string, e.g., for netconf operation
• B.reduce(A): remove all objects from B, which exist in A (create a canonical form)
• B.bind(A): resolve lefrefs; copy missing targets from A to B if needed
• A.merge(B): update A with changes from B; netconf operations are copied without execution
• C = A.diff(B): return a diff to go from A to B
• A.patch(C): apply C on A, i.e., A.patch(A.diff(B)) == B

Additional information

• UNIFY Deliverables