 Chapter 1: Understanding Cloud Fundamentals and the Cloud Continuum 13 Contractual open Public/private hybrid clouds ✓ A private cloud owned and managed by a company for  the benefit of its employees and partners ✓ A commercial private cloud resides in a vendor’s data  center and provides a secure connection to the customer’s  other IT resources. This approach securely augments a  customer’s IT environment. In some instances, companies use a combination of public and private cloud services. A retail company may have a private cloud to support its highly distributed development  These materials are the copyright of John Wiley & Sons, Inc. and any  dissemination, distribution, or unauthorized use is strictly prohibited. Companies often want the flexibility of the cloud but with the  security and predictability of the data center. In these cases, a  private cloud provides an environment that sits behind a fire- wall. Unlike a data center, a private cloud is a pool of common  resources optimized for the use of the IT organization. Unlike  a public cloud, a private cloud adheres to the company’s  security, governance and compliance requirements. Whatever  service level is required for the company applies to the pri- vate cloud. There are two different types of private clouds: In this kind of environment, the expectation is for a high level  of security, privacy, and governance. These vendors provide  a written SLA. Because of the service and security guarantees  of this model, some customers may be willing to store critical  data in the cloud. Public cloud vendors sometimes productize offerings. Here  the user can’t simply create login credentials, provide a credit  card, and start using the service. Instead, the user actually  signs a contract for service. The term can be as short as a  month, or more typically a year. Vendors are also offering  public IaaS and PaaS public platforms that are based on a  formal contractual basis.