Cloudify has decided to retire ariaTosca (see http://incubator.apache.org/projects/index.html#ariatosca) , vnfsdk pkgtools as an downstream user of ariaTosca, need to replace it with other maintained python tosca parser library, such as openstack/tosca-parser.

 In Casablanca, we'll add the openstack/tosca-parser as the new validator backend and develop HPA validation functions based on that. 

However, airaTosca and openstack/tosca-parser has conflicting dependency to python module requests. So we need to decide whether we should totally remove ariaTosca or make it optional during vnfsdk/pkgtools install and add documentation to tell user how to install aria if they choose to use that?

Based on discussion, maybe we should use https://pypi.org/project/nfv-toscaparser/ , it adds some additional type of extension for ONAP.