Private versus public clouds

Up until a few years ago, one of the biggest and most common objections to hamper cloud adoption on a massive scale was the refrain that the cloud is not secure. To address this objection, cloud providers started offering private clouds: a whole infrastructure setup that only one company can access and is completely private to them. However, this privacy and security come at a price. One of the reasons why the cloud is so popular and affordable is that any resources that you are currently not using can be used by other customers that do need the capacity at that time, meaning they share the cost with you. Whoever uses the resources the most, pays the most. This cost-sharing disappears with private clouds.

Let's use an analogy to gain further understanding. The gig economy has great momentum. Everywhere you look, people are finding employment as contract workers. There are Uber drivers, people setting up Airbnbs, people doing contract work for Upwork. One of the reasons contract work is getting more popular is that it enables consumers to contract services that they may otherwise not be able to afford. Could you imagine how expensive it would be to have a private chauffeur? But with Uber or Lyft, you almost have a private chauffeur who can be at your beck and call within a few minutes of you summoning them.

A similar economy of scale happens with a public cloud. You can have access to infrastructure and services that would cost millions of dollars if you bought them on your own. Instead, you can have access to the same resources for a small fraction of the cost.

A private cloud just becomes a fancy name for a data center managed by a trusted third party, and all the elasticity benefits wither away.

Even though AWS, Azure, Google Cloud Platform (GCP), and the other popular cloud providers are considered mostly public clouds, there are some actions you can take to make them more private. As an example, AWS offers Amazon EC2 dedicated instances, which are EC2 instances that ensure that you will be the only user for a given physical server. Again, this comes at a cost.

Dedicated instance costs are significantly higher than on-demand EC2 instances. On-demand instances may be shared with other AWS users. As mentioned earlier in the chapter, you will never know the difference because of virtualization and hypervisor technology. One common use case for choosing dedicated instances is government regulations and compliance policies that require certain sensitive data to not be in the same physical server with other cloud users.

Truly private clouds are expensive to run and maintain, and for that reason, many of the resources and services offered by the major cloud providers reside in public clouds. But just because you are using a private cloud does not mean that it cannot be set up insecurely, and conversely, if you are running your workloads and applications on a public cloud, you can use security best practices and sleep well at night knowing that you are using state-of-the-art technologies to secure your sensitive data.

Additionally, most of the major cloud providers' clients use public cloud configurations, but there are a few exceptions even in this case. For example, the United States government intelligence agencies are a big AWS customer. As you can imagine, they have deep pockets and are not afraid to spend. In many cases with these government agencies, AWS will set up the AWS infrastructure and services on the premises of the agency itself. You can find out more about this here:

https://aws.amazon.com/federal/us-intelligence-community/

Now that we have gained a better understanding of cloud computing in general, let's get more granular and learn about how AWS does cloud computing.