Cloud computing gets divided into three types: public, private, and hybrid; the last being a mix between the first two types.
While a public cloud connects to multiple users through the internet, a private cloud is restricted to only select users, such as a university, or a company.
The private cloud can be located directly on premise directly on the internal network, or at an off premises company owned and managed data center. Private cloud also gets known by the names corporate cloud, and internal cloud.
Virtual private cloud
A variation of the private cloud is the virtual private cloud (VPC). The difference is that a private cloud is hosted over the organization’s internal infrastructure, while the VPC uses a third-party’s cloud provider infrastructure. However, unlike a public cloud that serves multiple organizations, the VPC remains dedicated to a single organization.
An example of a VPC is the Amazon Virtual Private Cloud, a service of Amazon Web Services, which allows a Hardware Virtual Private Network connection from the AWS data center to the organization’s corporate data center for a high level of security. Such a solution can be a good intermediate step offering the features of a private cloud, while letting a vendor handle the heavy lifting of deployment and maintenance.
While a private cloud setup can most certainly exist on its own, these days, it frequently gets connected to a vendor’s public cloud server, in a hybrid cloud setup. This provides advantages of redundancy, and scalability to provide additional resources at times of peak demand, in what gets called ‘cloud bursting.’ In some setups for times of peak demand, less sensitive applications may be get shifted to the public cloud, so that additional hardware resources in the private cloud can be devoted to those applications that need to be run locally.
Advantages of private cloud
Let’s look at the advantages of a private cloud setup:
- Security - With a private cloud setup dedicated to a single client, security is inherently higher than in a public cloud situation that has multiple users.
- Control - The organization gains total control over the access to the server, and the data stored on it.
- Performance - With a private cloud, with the hardware on-premise, and therefore behind the firewall, latency will be lower, and therefore network speed is faster.
- Customization - With control over the hardware and infrastructure, components can be upgraded as needed, such as RAM and hard drives to optimize performance, and more resource intensive apps can be specified to run on the newer gear.
- Management - With a public cloud, the cloud provider is the top manager, but in a private cloud environment the IT administrator for the organization retains this.
Disadvantages of private cloud
There are also some disadvantages to the private cloud environment. One is that the startup costs for hardware acquisition are quite a bit higher than a public cloud. It can also be hard to budget for, as it is not always simple to plan out hardware failures.
The costs for maintenance, and that it is done cost effectively, also fall on the IT department, causing them to turn to public cloud solutions with their more predictable monthly costs that are simpler to budget for.
However, for the organization’s mission critical applications, the investment in a private cloud setup can be justified, as uptime can be more highly optimized with redundant hardware.
With a private cloud solution it can be a challenge to plan out the capacity. If it is overbuilt, it will be underutilized, and therefore money is wasted on resources that are not necessary. If the private cloud is underpowered, than it will not be up to the task, and not able to meet times of higher demand, although this has prompted some organizations to enable cloud bursting, as detailed above.
A final downside is that as the private cloud is located on the corporate LAN, there can be difficulties accessing it from outside the network, while maintaining a high level of security.
With the downsides of acquiring, deploying, and maintaining, a private cloud solution, it has come under criticism as public clouds offer economies of scale from companies that offer their expertise in this increasingly complex area. After all, public cloud offers resources on demand, at affordable prices. However, not all applications, often due to security and compliance with regulations, are amenable to a public cloud approach, necessitating a private cloud environment as the organization needs to maintain control over their sensitive data.
Private cloud software
To build out a private cloud requires software. There are plenty of choices from vendors, such as Microsoft Azure, VMWare vCloud, and the Amazon Virtual Private Cloud, each offering an array of services, including private clouds, virtual private clouds, and the ability to connect to a public cloud provider to implement a hybrid cloud solution.
Another popular solution is the Eucalyptus cloud platform, which stands for the Elastic Utility Computing Architecture for Linking Your Programs To Useful Systems and is open-source software that provides solutions for IaaS methodology. This grew out of a research project at the University of California, Santa Barbara, which then transitioned to the business Eucalyptus Systems in 2009.
Subsequently they decided to work with Amazon Web Services in 2012, to allow users to join their Eucalyptus private cloud to the Amazon Elastic Compute Cloud (EC2) for implementation of a hybrid cloud setup. Eucalyptus was subsequently acquired by HP in 2014, and integrated into their Helion portfolio.
Explaining the wide adoption of Eucalyptus has been their wide support across both Windows and Linux virtual machines, accounting reports for administrators, the ability to virtualize multiple clusters into a single cloud, secure internal communication via WS-Security between internal resources, and compatibility with popular hypervisors, including VMWare and KVM.
It continues to be a robust software platform, with an advanced feature set such as CloudWatch that can collect and study metrics to spot trends, and even provide alerts, Auto Scaling that can increase the resources as needed to match the workload, and scale them back when not needed, and granular reporting that can report the cloud utilization down to the cloud application by each user.
While private cloud only environments are giving way to hybrid cloud architecture, incorporating the innate advantages that the public cloud offers, they continue to be an important component to include for organizations seeking the most robust cloud architecture.