Stack fusion architecture including distributed software clusters to enable software communication services

A method comprising:

• establishing a distributed Software-as-a-Service (SaaS) system in which a cloud provider offers software services to multiple organizations, each organization to operate a distinct cluster of software services of the cloud provider, each cluster uniquely associated with an organization domain of the organization that operates the cluster, wherein users registered to a given organization domain have access limited to the cluster associated with that organization domain;
• storing a globally accessible domain-to-cluster map used to map each cluster to the organization domain uniquely associated therewith;
• storing in each cluster a locally accessible user-to-cluster map to map that cluster to each user registered to the organization domain associated with that cluster so as to have access thereto;
• receiving a user request for access to a software service offered by the cloud provider, the user request including a user email address;
• and
• directing the user request to the requested software service in a cluster uniquely associated with the organization domain to with the user is registered based on the user email address, the domain-to-cluster map, and one of the user-to-cluster maps.

A system comprising:

• multiple infrastructure-as-a-Service (IaaS) platforms each to be operated by a corresponding one of multiple organizations and being associated with at least one organization domain claimed by the organization that is to operate that IaaS platform;
• multiple clusters of software services, including communication services, deployed on corresponding ones of the IaaS platforms and being uniquely associated with the organization domain corresponding to the organization that operates that IaaS platform on which the cluster is deployed, wherein the software services include offerings from a cloud provider;
• a globally accessible domain-to-cluster map to map each cluster to the organization domain uniquely associated therewith;
• and
• a locally accessible user-to-cluster map stored in each cluster to map that cluster to each user provisioned on that cluster;
• wherein users that belong to each organization domain are provisioned only on the cluster uniquely associated with that organization domain, such that user information for each user is stored only on the associated cluster;
• and
• wherein users provisioned on different clusters are enabled to communicate with each other as if the users were part of a centralized cloud communication service, and without sharing respective user information with the cloud provider.