何謂私人雲端？

Private clouds are operated behind a single owner's firewall, because of this, they are referred to as single-tenant environments with isolated access to resources. Compared to public CSP, private cloud infrastructure is usually hosted on-premises in the owner’s data center. Alternatively, the company can rent infrastructure from an IaaS vendor placing their infrastructure offsite but still under company control. In either case, virtualization is the key technology that enables both private and public clouds.

Virtualization uses various technologies to abstract the physical infrastructure from the mind of the user—in the end, cloud consumers will see only the cloud and its capability to host a seemingly infinite amount of data and services. Underneath, virtualization turns compute resources into a centralized, sharable pool of resources that an organization can allocate to its business units on demand, while still maintaining control of resources and applications.

Cloud management platforms offer IT administrators visibility that assists them in controlling and extending the private cloud resources. Integrations with cloud infrastructure monitoring software and infrastructure automation software extend these management platform capabilities for private clouds in much the same way that public CSPs. By monitoring and automating many tasks CSP adds easy capacity scaling while reducing human error.

In a private cloud deployment model, ownership of the cloud is the primary benefit for companies. Ownership guarantees companies complete control over configuration and access to IT resources in the most effective and efficient deployment for their needs. They can customize based on staff, departments, and regional locations. Private cloud solutions are usually implemented behind the corporate firewall allowing the following benefits.

• Complete control over infrastructure and software choices — Because private clouds are owned and operated behind a corporate firewall, all infrastructure and software choices are open, which grants companies the freedom to develop and deploy assets to match their most particular needs. However, this also holds companies responsible for maintaining their network systems, including scaling if needed, and responding to performance and security threats.
• Maximum control over configurations and customization — Companies have different needs. Complete control over infrastructure purchases enables companies to also configure and customize based on organizational structure and business goals.
• Ownership of network visibility and security measures — Operating private clouds can allow owners greater visibility into their networks provided that network performance and visibility software or appliances are in place.
• Ownership of compliance responsibilities — Depending on the industry, particularly education, health, finance, and utilities, compliance is staggeringly strict. While public CSPs have programs that assist with compliance, sometimes the nuances are too much and the risk too great to relinquish compliance to outside vendors. Private clouds allow enterprises with vast and complex user data to build custom systems to comply with regulations and protect their customers.

While not a guarantee, owning and operating private clouds tend to cost more than other public cloud options. For small and medium businesses, public clouds often prove to be strategically better choices since much of the IT responsibilities are offloaded onto the CSP, effectively reducing the cloud consumer’s IT department to a budget line item.

A virtual private cloud (VPC) is a “cloud within a cloud” configuration where an organization establishes a private virtual networking environment within a cloud service provider’s public cloud. This “private cloud in the public cloud” usually grants complete control over the private virtual space, security, and where resources are located depending on availability by the CSP. The major benefit of the VPC deployment is to offload infrastructure risk onto a CSP, with many subsequent benefits like reduced IT staff, and associated infrastructure and staffing costs, and future-proofing the organization's tech stack.

There are similar concepts that sometimes are crossed with VPCs, such as virtual private servers, and virtual private networks. Virtual private clouds are very similar to virtual private servers (VPS) but with significant differences. A VPS, like a VPC, exists in the cloud, but uses only a fixed portion of the server with fixed resources—when accessing VPS, users can interface with it as if it were a local drive. A VPS lacks efficient scalability, which distinguishes it from other virtual cloud models. A VPC, contrastingly, is not bound by the underlying infrastructure, but rather their architecture allows them to scale on-demand.

VPNs are not a server technology. Virtual private networks (VPNs) allows users to securely access a company's intranet from outside the firewall, and can be said to make a secure line over a public network like the Internet. Likewise, a worker can use a VPN connection to securely connect to a company’s VPC from anywhere they can access the Internet. VPNs are used to secure connections and transmit and receive data privately.

Private cloud management best practices develop a foundation of sustainability. The following practices create shared understanding and central thinking that reduces management burden.

• Standard Operating Procedures — SOPs ensure that tasks are performed consistently and without deviation from standards. After SOPs are established, moving to automation offloads mundane and repetitive maintenance and other tasks from IT staff.
• Workflow Modeling — Workflows organize business processes into discrete tasks from the beginning to the end of an operation. Workflow modeling visualizes workflows by situating a task on a timeline and including dependencies to show prerequisite or parallel tasks that form paths of independent tasks. Performing critical path analysis identifies those paths that during peak times should be granted the highest priority.
• Capacity Management — Capacity management is the process of ensuring that current and future IT capacity and performance can be delivered with reasonable costs. By baselining operations and understanding network performance and usage, and utilizing network monitoring and capacity planning tools, IT teams can easily determine their current and future capacity needs.