Cloud Deployment Models – Public, Private and Hybrid Cloud

In this cloud training tutorial, I’m going to cover the four cloud deployment models as defined by NIST. These are the Public Cloud, Private Cloud, Community Cloud, and Hybrid Cloud deployment models. Scroll down for the video and text tutorial.

This is part of my ‘Practical Introduction to Cloud Computing’ course. Click here to enroll in the complete course for free!

Cloud Deployment Models – Public, Private and Hybrid Cloud Video Tutorial

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Cloud Deployment Models - Public, Private and Hybrid Cloud Video Tutorial

Public Cloud

First, the Public Cloud. As NIST defined it, the cloud infrastructure is provisioned for open use by the general public. It may be owned, managed, and operated by a business, academic, or government organization, or a combination of them. It exists on the premises of the cloud provider.

Public Cloud Examples

Examples of public cloud are the well-known cloud providers like Amazon Web Services, Microsoft Azure, IBM Bluemix is a PaaS example, and Salesforce is a SaaS example.

All of these are cloud providers, which sell their services to the general population. Public Cloud is by far the most common deployment model.

Private Cloud

NIST defines Private Cloud as the cloud infrastructure that is provisioned for exclusive use by a single organization comprising multiple consumers. For example, 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.

Private Cloud works the same way as Public Cloud, but the services are not provided to external public enterprises. They are provided to the organization’s own internal business units.

How is Private Cloud Different than On Prem?

There can be a bit of confusion about how is Private Cloud different than on premises then, if it’s just operated for a single company.

The difference is that Private Cloud fulfills the cloud essential characteristics such as on-demand self-service, rapid elasticity, broad network access, resource pooling, and measured service.

Private Cloud will fulfill all of those characteristics, whereas an on-premises solution does not. The most obvious example with that is with a traditional on premises model, a business unit orders a new server by raising a ticket with the IT department.

The server is then provisioned and configured by the server, network, and storage teams as separate manual processes. With Private Cloud, however, a business unit orders a new server typically through a web portal. The server is then automatically provisioned without requiring any manual intervention.

If you remember the tutorial about on-demand self-service, I showed you about how we could provision a virtual server in AWS, through the web portal.

I configured all the settings that I wanted for my virtual machine. Then, in the background, automation software deployed everything automatically, and the virtual machine was up and running in 15 minutes.

With a traditional on premises model, everything would be done manually and it would typically take a week or more to get the server up and running. But just like with Public Cloud, when the business unit provisions a virtual machine, it’s all going to be done in the back end automatically.

It will be using automation software, like BMC, CA Technologies, or Cisco UCS Director. There’s a lot of other automation software available and if the company’s big enough, they can even end up developing it themselves.

Private Cloud is most suitable for large companies where the long term ROI and efficiency gains that you’ll get from the solution can outweigh the initial effort and cost to set up the infrastructure and automated workflows.

A Private Cloud is an expensive solution because the data center is dedicated just for that one customer. All of the infrastructure there is just for one customer, so it’s going to be very expensive to get the data center set up.

Also, for everything to be automated, this all needs to be set up ahead of time. That automation software will need to be deployed, all of the workflows will need to be written, and all of the integration between the front end and the back-end components such as the storage, the networking, and the server will all need to be developed and tested as well.

It’s expensive and time consuming for Private Clouds to get up and running. But if a company is big enough, they can make long term cost savings from doing this.

Private Cloud Examples

There aren’t many well-known examples of Private Cloud, because companies with Private Cloud don’t usually advertise because it’s private. However, a well-known example is the US Department of Defense on Private Cloud, which is provided by AWS.

Not Really ‘Private Cloud’

That’s an example of Private Cloud owned, managed, and operated by a third party, rather than the company that’s using it themselves. I also want to give you some information on something that’s sometimes called ‘Private Cloud’, but it is really not.

Public Cloud IaaS providers will sometimes market dedicated servers as Private Cloud because the underlying servers are dedicated for a particular customer. It’s not a true Private Cloud because it is only the servers that are dedicated for the particular customer.

The supporting network infrastructure, like the switches, the routers, the firewalls, etc., is shared. This is not a true Private Cloud. For a true Private Cloud, the entire solution is dedicated to a particular customer, not just the servers.

Community Cloud

The next deployment model is Community Cloud. NIST defined this as the cloud infrastructure provisioned for exclusive use by a specific community of consumers from organizations that have shared concerns, such as mission, security requirements, policy, and compliance considerations.

It may be owned, managed, and operated by one or more of the organizations in the community, a third party, or some combination of them. It may exist on or off premises.

Community Cloud is similar to a traditional extranet. To give you an example of that, I worked for an oil and gas company before. We had private network connectivity with other oil and gas companies, such as BP and Shell, so that we could share information with each other.

Community Cloud is a little bit different than that, it is full shared data center services instead of just network connectivity between the on premise offices. Community Cloud is also the least common deployment model.

Hybrid Cloud

The final model is the Hybrid Cloud. This is defined by NIST as the cloud infrastructure with a composition of two or more distinct cloud infrastructures that remain unique entities, but are bound together by standardized or proprietary technology that enables data and application portability, like cloud bursting for load balancing between clouds.

You saw the term cloud bursting, what this is about? Companies with limited Private Cloud infrastructure may cloud burst into Public Cloud for additional capacity when required.

For example, I’ve got my own Private Cloud infrastructure at my company and my data center, but I have limited capacity because I’ve got many servers. Now, a way that I could scale is by growing my own Private Cloud. I would have to pay for the hardware for that, which would be expensive.

A way that I can make it more cost-effective is that, if I’m running out of capacity in my Private Cloud, then I can burst and expand into a Public Cloud. A company could also have a Private Cloud at their main site, and use Public Cloud for their disaster recovery solution.

That’s quite common because building the Private Cloud infrastructure is expensive. If we wanted to double that for a disaster recovery site, that’s going to take the cost even higher.

We could bring the cost down by having the main data center as a Private Cloud, and then use Public Cloud for our disaster recovery site.

Additional Resources

Public Cloud vs Private Cloud vs Hybrid Cloud: What’s The Difference?: https://www.bmc.com/blogs/public-private-hybrid-cloud/

Demystifying Clouds: Private, Public, and Hybrid clouds: https://hub.packtpub.com/cloud-deployment-models-private-public-hybrid/

Cloud Deployment Model: https://www.sciencedirect.com/topics/computer-science/cloud-deployment-model

This is part of my ‘Practical Introduction to Cloud Computing’ course. Click here to enrol in the complete course for free!

Libby Teofilo

Text by Libby Teofilo, Technical Writer at www.flackbox.com

With a mission to spread network awareness through writing, Libby consistently immerses herself into the unrelenting process of knowledge acquisition and dissemination. If not engrossed in technology, you might see her with a book in one hand and a coffee in the other.