What is Cloud Computing?

IaaS (Infrastructure-as-a-Service), PaaS (Platform-as-a-Service), and SaaS (Software-as-a-Service) are the three most common models of cloud services.

• IaaS provides on-demand access to fundamental computing resources–physical and virtual servers, networking, and storage—over the internet on a pay-as-you-go basis.
• PaaS provides software developers with an on-demand platform—hardware, complete software stack, infrastructure, and development tools.
• SaaS—also known as cloud-based software or cloud applications—is application software that’s hosted in the cloud accessible via a web browser or app.

Serverless computing (also called simply serverless) is a cloud computing model that offloads all the backend infrastructure management tasks–provisioning, scaling, scheduling, patching—to the cloud provider, freeing developers to focus all their time and effort on the code and business logic specific to their applications.

A subset of serverless. FaaS allows developers to execute portions of application code (called functions) in response to specific events.

Public cloud is a type of cloud computing in which a cloud service provider makes computing resources—anything from SaaS applications, to individual virtual machines (VMs), to bare metal computing hardware, to complete enterprise-grade infrastructures and development platforms—available to users over the public internet.

A private cloud is a cloud environment in which all cloud infrastructure and computing resources are dedicated to, and accessible by, one customer only. Private cloud combines many of the benefits of cloud computing—including elasticity, scalability, and ease of service delivery—with the access control, security, and resource customization of on-premises infrastructure.

A hybrid cloud is just what it sounds like—a combination of public and private cloud environments. Specifically, and ideally, a hybrid cloud connects an organization's private cloud services and public clouds into a single, flexible infrastructure for running the organization’s applications and workloads.

Multicloud is the use of two or more clouds from two or more different cloud providers. Having a multicloud environment can be as simple as using email SaaS from one vendor and image editing SaaS from another.

Hybrid multicloud is the use of two or more public clouds together with a private cloud environment. Organizations choose multicloud to avoid vendor lock-in, to have more services to choose from and to access to more innovation.

Traditionally, security concerns have been the primary obstacle for organizations considering cloud services, particularly public cloud services. In response to demand, however, the security offered by cloud service providers is steadily outstripping on-premises security solutions.

Some cloud security best practices include:

• Shared responsibility for security
• Data encryption
• User identity and access management
• Collaborative management
• Security and compliance monitoring

With 25% of organizations planning to move all their applications to the cloud within the next year, it would seem that cloud computing use cases are limitless.

Disaster recovery and business continuity:

The cloud provides cost-effective redundancy to protect data against system failures and the physical distance required to recover data and applications in the event of a local outage or disaster.

All of the major public cloud providers offer Disaster-Recovery-as-a-Service (DRaaS).