There are two primary actors in a cloud deployment, the customer of the cloud (Tenant) and the provider of the cloud (Provider). They represent a standard client / server relationship requiring a strong contract and visible performance against that contract.
I believe that there are a set of key capabilities required in order to maximize the adoption [by Tenants] of [Provider] cloud infrastructure. They are detailed as follows.
- Flexibity
- The cloud is dynamic in nature; tenant boundaries shift to meet business needs and locations change in response to overall workloads to meet contractual SL0s and to manage availability
- Virtualization is required to support this operational model
- Agility
- The speed of contracting for services verses the capital budget, procurement, and deployment lifecycle to purchase the capacity will have a significant advantage in responding to the speed of business.
- Elasticity
- Empowerment to expand and contract capabilities as and when business requirements change and opportunities arise.
- Economy [of Scale]
- Simply shifting infrastructure from Customer to Cloud Provider will not provide Economies of Scale.
- Cloud Providers must be able to pool and share their infrastructure resources in order to achieve Economies of Scale for their Customers.
- Multi-Tenancy is the Key to saving of massive amounts of capital and maintenance costs trough sharing of pooled resources via cloud operating systems.
- Trust [and trusted]
- Multi-Tenancy yields cost savings, but Customers will NOT adopt Cloud Services unless they can be assured that the Cloud environment provides a higher level of granularity of visibility and control than their existing infrastructure
- Trusted Multi-Tenancy is the Key to Cloud adoption.
These capabilities follow with a set of Tenant requirements (expectations):
- Improved Control of and Visibility into the Environment
- Self-service using web-based controls
- Improved visibility of both function and expense
- Transparency in operations and comp liane
- Isolation from other tenants; must ensure
- Privacy
- protect data in use amp; data at rest
- Non-interference
- ensure their SLOs are met, regardless of other tenant workloads
- Privacy
- Security
- Identity
- Single Sign-On (SSO) federated from Enterprise to SP
- Ability to control access to shared resources (data path, control path, and key management/escrow)
- Identity
- Improved performance to expense ratio (shared capital)
- Reliability
- Operational agility (contract/expand)
As we distill the functional requirements, an architectural taxonomy of affected entities naturally emerges:

Then we must evaluate our core architectural tenets of trusted multi-tenancy (please excuse the pun):
- Make customer-visible units of resources logical not physical
- Known MT properties/capabilities on any layer directly exposed to customers
- Put those logical objects into containers [nested] with recursive delegated administration capabilities @ the container layer
- Separates the implementation of a resource from its contract
- Provides a common point of mediation and aggregation
- Hierarchical (Layered) relationships must be supported on the data path and the control path
- Implement out-of-band monitoring of management activity
- Verify actual state of system remains in compliance throughout management / state changes across tenancies
- Out-of-band monitoring must be done at the container boundary for the container to support multi-tenancy
- Multi-Tenant correlation (actual vs. expected) becomes critical to GRC
And lastly we believe that these further distill into a set of discrete design factors and principles that help to create a matrix of critical requirements:
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I hope that this discussion of Trusted Multi-Tenancy helps to clarify the complexity of the Tenant / Provider relationship as well as the complexity of the infrastructure required to fulfill Tenant service requirements in a cloud setting.
I want to thank the EMC team including Jeff Nick, John Field, Tom McSweeney, the RSA team at large as well as the 30+ members of our working group for the work that precluded this blog. – Dan


In my view, this is an environment designed, not for the traditional system administrator, but for the hyper-productive, administrative developer. Not catering to the lowest common denominator, the flexibility afforded by the PL approach can help to tear down some of the old walls between development and deployment in a valuable and empowering way.
This slide from one of my presentations supports the similarities of building a shopping mall alongside the development of a big data community. Things like understanding the demographics of the community (information needs, key values), the planning of roads to get in/out. And of course how to create critical mass = the anchor store.