Private cloud - in so many ways

Following my post about the 5-3-3 of cloud computing, I've spent some more time of the various ways one can build, manage and operate a private cloud solution.

Firstly, there are a number of definitions of private cloud, for instance

1. Wikipedia: " Private cloud is cloud infrastructure operated solely for a single organization, whether managed internally or by a third-party and hosted internally or externally"
2. NIST: "The cloud infrastructure is provisioned for exclusive use by a single organization comprising multiple consumers (e.g., business units). It may be owned, managed, and operated by the organization, a third party, or some combination of them, and it may exist on or off premises."
3. Microsoft: "Private cloud is the implementation of cloud services on resources that are dedicated to your organization, whether they exist on-premises or off-premises. ... "
4. Webopedia: "Private cloud is the phrase used to describe a cloud computing platform that is implemented within the corporate firewall, under the control of the IT department."
5. Gartner: "Private cloud computing is a form of cloud computing that is used by only one organization, or that ensures that an organization is completely isolated from others".

Looking at this, there seems to be general acknowledgment that a private cloud solution needs to be or can be:

• Provisioned for exclusive use by a single business organisation (that can, of course, have many business units)
• Cloud resources or infrastructure is dedicated for the business organisation - or at least "completely isolated from others", i.e. a private cloud can run on shared infrastructure as long as there is complete resource, ID, usage, logging and management isolation between different business organisations
• Hosted and managed internally or by 3rd party on internal or external DC or service platform
• Doesn't need to be "inside the firewall" or on internal DC

Overall, resource control and service delivery isolation seems to be the key criteria, giving the appearance of "dedicated infrastructure and delivery", with internal or 3rd party management and delivery, internal or 3rd party DC taking a back seat. This in turn leads to, at least on paper, that reserved capacity VMs on public cloud can be used to create private cloud solutions, but with SLAs even for reserved VMS or instances, this options is still far off from bare-metal or single-user virtualized servers to create private clouds with proper resource control and isolation.  

Also, all the parts that makes up the private cloud solution has to have resource control and resource utilization isolation according to the business requirements for a private cloud, including storage, VM and DC networking, firewalls, load balancers, VPNs or Internet access etc.

This leads to the following aspects as how a private cloud solution can come about, no doubt in many cases crossing over to hybrid cloud delivery territory:

• On-demand and self-service: Yes, must have
• Ubiquitous network access: Yes, must have
• Location transparent resource pooling: Yes, must have
• Rapid elasticity: Yes, must have
• Measured service with pay per use: Yes, must have
• SaaS-delivery: Private clouds can be used for SaaS delivery
• PaaS-delivery: Private clouds can be used for PaaS delivery
• IaaS-delivery: Private clouds can be used for IaaS delivery
• Dedicated resources: Can use dedicated IT resources, or shared resource with resource control and service delivery isolation
• Dedicated hardware: For the organization, but private cloud doesn't necessarily require dedicated hardware
• Shared hardware/servers/infra: Can be used if resource control and isolation
• On-prem DC (company internal): Can be used
• 3rd party DC: Can be used
• Cloud-based: Can use public cloud provider or solution as long as resource control and isolation meets business requirements
• Internet access: Not general, public Internet access to private cloud solution, but can use Internet access for secure access to and log-in to private cloud solution
• VPN access: Yes, gives greater resource utilisation control
• Private link access: "