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IT用語辞典

Infrastructure as a Service

What is Infrastructure-as-a-Service (IaaS)?

Infrastructure-as-a-Service (IaaS), also sometimes called hardware-as-a-service (HaaS) describes a common delivery model for cloud services where customers purchase access to managed IT infrastructure from a third-party cloud service provider. Service providers in the IaaS space provide infrastructure to customers that can include hardware, servers, storage, and data center space, along with the networking components needed to enable access and management of the leased assets.

IaaS differs from other models of cloud service delivery in terms of which aspects of the technology stack are managed by the cloud service provider and which components are managed in-house by the customer IT organization. The three most common deployment models for cloud services are software-as-a-service (SaaS), platform-as-a-service (PaaS) and infrastructure-as-a-Service (IaaS).

In the SaaS model, the cloud service provider manages the entire technology stack and the subscriber pays a monthly fee to access the software application via the internet. In the PaaS model, the cloud service provider manages all of the hardware and infrastructure while providing a platform that includes the operating system, middleware, and runtime. The subscriber can scale the platform as needed to deploy applications of their choosing.

In the infrastructure-as-a-service (IaaS) model, the subscriber leases just the hardware infrastructure (networking, data center space, storage, servers, and virtualization services), but establishes and maintains all other components of the technology stack (applications, data, runtime, middleware, operating systems, etc.).

Key Characteristics of Infrastructure-as-a-Service

IaaS offers a flexible and dynamic solution for IT organizations or software developers that wish to address their IT infrastructure needs with a cloud-based outsourcing model. Organizations seeking cloud-based solutions should be aware of these five important characteristics associated with the IaaS outsourcing and pricing model:

  • Resources-as-a-service - The cloud service model is based on the concept of resources-as-a-service. As an alternative to spending money on the up-front equipment costs associated with creating and managing a server room or data center, the cloud service model allows organizations to access and implement IT infrastructure with a subscription-based payment model that's more affordable.
  • Pay-as-you-go Pricing Model - IaaS services are provided on an on-demand basis and billed on a pay-as-you-go basis, making them a cost-efficient option for smaller organizations that can only afford to pay for computing resources that they use. An IaaS provider might bill according to the number of virtualization instances that are created, or based on the quantity of data stored. Some cloud service providers may bill extra for specified managerial services.
  • Scalable Services - The ability to quickly and easily scale service is one of the major benefits of the IaaS model. Cloud service providers maintain data centers with large volumes of servers and data storage available, which can be apportioned to a customer upon request. This significantly cheapens and simplifies the process of scaling up IT infrastructure for subscribers to IaaS services compared to organizations that deploy IT infrastructure in an on-premise data center.
  • Automated Administrative Tasks - IT organizations that manage data centers and hardware infrastructure in the on-premise model are responsible for routine updates, patches, and maintenance activities that can affect the availability of hardware resources and the software applications that depend on them. In contrast, IaaS service providers handle upgrades and maintenance to their servers without compromising infrastructure availability for customers.
  • Platform Virtualization - Platform virtualization refers to the creation of a virtual machine that acts as a logical abstraction of a hardware platform. The main purpose of virtualization is to divide the resources of a mainframe computer between different functions and applications and to segment those environments from each other for operational or testing purposes. Platform virtualization enables IaaS subscribers to deploy virtualized computing instances as needed to support software development and other tasks.

Infrastructure-as-a-Service Advantages and Benefits

The cloud service model is becoming increasingly popular as organizations seek out more cost-effective ways to expand their IT infrastructure and leverage technological resources at the best price point to drive business success. While SaaS is still the most popular delivery model for cloud services, there are a few key reasons why more IT organizations are choosing to engage with the IaaS cloud service model.

Reduced Costs and Up-front IT Infrastructure Investment

IT organizations can reduce their up-front expenditures on IT infrastructure by choosing a cloud-based delivery model such as IaaS. Cloud service providers make it easy for organizations to access business-critical IT infrastructure and scale their operations as needed based on the current level of demand.

Improved Availability and Continuity

Imagine that your business purchases a server to host a critical business application. When you need to perform server maintenance, the server has to be taken offline and the application is made unavailable. In the IaaS model, your cloud service provider can simply host your application on a separate server while conducting maintenance and your application can be re-deployed on another server or virtual machine if the current one fails. Cloud service providers can also mirror your data on additional servers, creating redundancies to prevent data loss and ensure optimized service availability and business continuity for your organization.

Reduced IT Labor Overhead

IaaS services reduce the amount of labor and knowledge that organizations need to maintain their IT infrastructure. In the IaaS model, the cloud service provider manages and updates the data centers, servers, and other hardware, leaving subscribers free to focus on their core business activities rather than the never-ending maintenance tasks associated with managing a data center.

Use Cases for Infrastructure-as-a-Service (IaaS)

Software Testing and Development

The availability of virtual machines makes it easy for software development teams to quickly initialize and dismantle test and development environments with desired characteristics. Streamlined testing enables new software development strategies such as continuous delivery and deployment, and helps teams bring their product to market faster.

Web-based Application Deployment

IaaS infrastructure is ideal for hosting and supporting web-based applications and includes the capability to increase available resources to support the application during periods of higher-than-normal demand.

Big Data Analysis

Organizations that wish to analyze large data sets require a huge amount of computing power. IaaS provides a budget-friendly option for organizations that need to recruit large volumes of computing power for data mining and analysis purposes.

Infrastructure-as-a-Service Security Challenges and Solutions

Security is a major concern for organizations that subscribe to IaaS, especially those that lease infrastructure in a shared public cloud. As organizations increase the number of applications deployed into the cloud, it can become increasingly difficult to accurately monitor network security events, detect and evaluate security threats, and maintain certainty about the organization's security posture.

Sumo Logic's security analytics tool offers an integrated view of network security in the cloud, helping IT organizations monitor and investigate security threats across an entire private, public, or hybrid cloud environment.