Summary
Highlights
Many organizations build their own private cloud, managing their own data centers, purchasing equipment, and maintaining everything themselves. This is often called an internal or private cloud, with resources dedicated solely to their use. While there's a significant upfront cost for equipment, there are no ongoing pay-as-you-go fees associated with a public cloud.
Organizations that prefer not to own or maintain equipment use external or public clouds, such as Amazon, Rackspace, or Microsoft. In a public cloud, multiple customers share the same underlying resources (storage, CPUs, network) but their data remains separate. While there are no upfront costs, users pay for the resources they consume, often through metered or fixed-rate pricing.
Cloud services can be billed with metered utilization, where you pay for the exact amount of resources used, such as ingress (upload) and egress (download) traffic, and storage. Costs fluctuate based on usage. Alternatively, non-metered pricing involves a fixed price for a set amount of resources, typically based on maximum storage capacity, regardless of actual usage.
Cloud computing offers elasticity, allowing organizations to instantly scale up or down their infrastructure based on demand. This means you can add resources when customer activity is high and reduce them when it's slow, paying only for what you need. This scaling can often be automated.
Cloud technologies prioritize high availability through redundancies across multiple data centers. If one component or data center fails, others pick up the load, ensuring continuous uptime. The cloud also enables global data synchronization, automatically duplicating information across data centers worldwide, which can be managed by the application or by the cloud provider.
Multi-tenancy is a characteristic where many different customers share the same cloud infrastructure simultaneously. Cloud providers implement technologies and procedures to maintain strict separation between these customers, allowing for efficient use of equipment and cost savings for users. This shared resource model drives overall efficiency in cloud technology.