  In this paper, we describe a virtual services marketplace, called Nubo,
designed to connect buyers of virtual services (or tenants) with providers of
those services on a cloud computing platform. The marketplace is implemented as
a collection of distributed microservices along with a marketplace portal that
runs as a Web application. The heart of Nubo is the Saranyu tenant and service
management microservice. Saranyu is a decentralized application (dApp) built on
top of the J.P. Morgan Quorum blockchain. Tenant and service accounts are
represented as static (nonnegotiable) smart contracts written in the Solidity
language. Quorum provides a tamper evident and tamper resistant distributed
ledger, whereby multiple cloud and service providers can co-operate to provide
service resources to tenants in a trustworthy fashion. Services offer resources
consisting of a collection of attributes describing what the tenant can
consume, and tenants subscribe to service resources through the Nubo
Marketplace portal. The Service Manager microservice provides multitenant
support for containerized services built for deployment and orchestration using
Docker that were originally not designed to be managed through Saranyu. We
discuss our design goals for Nubo, describe the overall architecture, discuss
some details on how Saranyu uses the blockchain and smart contracts, and
provide comprehensive performance and scalability data measured on the Saranyu
REST API. The results indicate Saranyu is competitive with published results
for comparable operations on the Havana release of OpenStack Keystone, but
Saranyu provides a much richer collection of tenant and service management
functionality than Keystone.
