With elastic multitenancy, application instances (tenants) are isolated logically, but integrated physically. The degree of logical isolation must be complete, but the degree of physical integration varies. The tenants can be organizations using one multitenant application or multiple applications competing for shared underlying resources. Multitenancy may also be nested when tenants are independent software vendors (ISVs) with their own subtenants. Multitenancy is elastic when resources are redistributed among tenants on-demand.