第12章クラウドネイティブアプリケーション開発

By the end of this section, you will be able to:

• Understand cloud deployment technology

• Relate to cloud deployment technology options

• Explain cloud deployment technology use cases and implementation

• Select cloud deployment technologies

• Relate to the future of cloud deployment technologies

Various cloud technologies may be used to deploy cloud-based and cloud-native applications. These technologies differ in their implementation and use. While these technologies span storage, network, and compute services, the emphasis will be on compute options. There are many deployment options available, and there is no right or wrong choice. Only a subset of these options is applicable to the deployment of cloud-native applications. However, all options will be covered because enterprise solutions are typically hybrid solutions that may combine on-premises, cloud-based, and cloud-native components. Many organizations will need to implement more than one option. Accordingly, selecting the best option to support workloads while controlling complexity can be a daunting task.

The delivery of computing services, such as databases, software, analytics, and storage over the Internet is called cloud computing. The cloud computing model is composed of three service models—Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS)—and four deployment models—private cloud, community cloud, public cloud, and hybrid cloud. Figure 12.20 describes the relationship between cloud deployment models, service models, and cloud deployment technologies.

When examining workload and service deployments, there are three key architectural considerations. First, the deployment models in the cloud are evaluated, offering choices for where service models are deployed, such as public, hybrid, community, or private cloud environments. Second, the service model options are assessed to determine the level and type of services, including Infrastructure as a Service (IaaS) and Platform as a Service (PaaS). Each of these cloud service models will be discussed in more detail. Finally, workloads and services are actualized in the cloud using various deployment technologies, ranging from bare metal (i.e., high-performance physical servers dedicated to a single customer where the burden of provisioning, maintaining, or scaling applications on these servers falls on the customer) to serverless computing (i.e., where customers deploy applications without the burden of provisioning, maintaining, or scaling these applications as they are provided by the cloud service provider). These technologies serve as the foundation for executing cloud-based and cloud-native applications, allowing organizations to harness the benefits of cloud computing. Understanding these options empowers companies to select the most suitable approach, ensuring performance, deployment speed, scalability, portability, and security align with business requirements while managing costs effectively. Enterprises must consider different factors when deploying various workloads and services in a cloud environment. For instance, high-performance computing (HPC) demands significant compute and memory resources, whereas legacy applications may have lower resource requirements.

The three cloud service models—IaaS, PaaS, and SaaS—define a combination of information technology resources (e.g., compute servers, storage, memory, middleware) offered by a cloud provider and are not mutually exclusive. These service models change the way information technology (IT) resources are consumed. Traditionally, IT resources were purchased, managed, and maintained in a company’s on-premises data center. The cloud computing service models, in contrast, provide a more economical solution where these IT resources are accessed and scaled on-demand from a cloud service provider at a predictable cost. These service models are categorized as Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). The following sections elaborate on these three cloud service models.

Infrastructure as a Service (IaaS) is on-demand access to a cloud-hosted computing infrastructure that includes servers, storage, and network resources. These resources can be provisioned, configured, and used by the customer like on-premises resources are. The difference is the cloud service provider hosts, manages, and maintains these resources in its own data centers, as shown in Figure 12.21.

IaaS customers access these resources via the Internet and pay for these services on a subscription or pay-as-you-go basis. Infrastructure consists of three main components: compute for processing tasks, storage, and network. The compute component could, for example, include a general-purpose processing capability or more specific processing capabilities such as a high-speed graphics processor (GPU) or high-performance computing (HPC). The storage component could support different storage needs such as object storage, block storage, or file storage. Finally, the network component allows for the compute and storage components to communicate.

IaaS resources are multitenant and are made available to multiple different customers simultaneously. The cost for the services varies depending on the technologies chosen. IaaS customers make use of these services on-demand where the demanded resources are provisioned and delivered to the customer in a matter of minutes or hours as opposed to days, weeks, or months as is with traditional IT on-premises resources. IaaS also provides the flexibility for customers to scale up or down resources depending on their needs.

As discussed previously, IaaS is a set of compute, storage, and networking resources that have been virtualized by a cloud service provider and configured by the customer to suit their needs. PaaS takes advantage of all the virtualized resources from IaaS and adds to this. Platform as a Service (PaaS) is on-demand access to a cloud-hosted platform for developing, running, and managing applications by prepackaging middleware, language runtimes, and tools as containers. The cloud service provider hosts, manages, and maintains all the software included in the platform. This includes the servers, storage, and networking services. It also includes the operating system, middleware, and runtime environment. Figure 12.22 illustrates how PaaS customers can deploy their application and data.

PaaS generally makes it easy to get an application up and running quickly. PaaS is cost effective in that customers don’t have to bear the cost to manage the runtime environment for their applications. PaaS cloud providers generally provide tools such as DevOps and collaboration tools, as well as API marketplaces as services that could easily be integrated with applications. PaaS also provides the flexibility for customers to scale resources up or down depending on their needs.

Software as a Service (SaaS) is a cloud-hosted, ready-to-use software or application that end users access with a client (e.g., web browser, desktop client, mobile app) via a subscription model. SaaS takes advantage of all the resources from PaaS, but also includes the application and data, as shown in Figure 12.23.

Unlike IaaS and PaaS, SaaS has the highest level of abstraction where the cloud service provider hosts, manages, and maintains all layers of the stack, including the application as well as all the infrastructure required to provide the application service. This allows for the SaaS application to always be upgraded to the latest version. SaaS applications are scalable at any level of the stack. Additional infrastructure resources such as compute power and platform resources, such as databases, can be added as needed.

SaaS resources are also multitenant where multiple users are all accessing the same pool of resources. Tenants would have access to the same hosted environment; however, they would have their own dedicated space to securely store their data. SaaS applications are cost effective compared to the other cloud service models because the cloud service provider maintains and manages the entire stack. SaaS applications are also cost effective compared to traditional applications hosted on-premises where companies would have to bear the cost of the hardware in addition to continued cost for IT support.

One important benefit of cloud computing is automation. Depending on the service model chosen, organizations can reduce the layers of management of hardware, infrastructure, and applications. This reduces costs and effort of investment into these resources and allows organizations to focus more on innovation. For an organization to choose between the cloud service models and on-premises solutions, it must balance the level of complexity and effort of investment in each solution. These solutions present a spectrum from complex and high effort of investment to simple and low effort of investment, as shown in Figure 12.24.

On-premises and IaaS solutions offer the greatest level of flexibility but are the most complex and require more effort of investment. These solutions also increase costs as they require the hiring of systems personnel as these solutions require a higher level of knowledge and management of infrastructure resources. Moving from left to right, PaaS solutions are less complex with less effort of investment and are generally managed by application developers. Finally, SaaS is the least flexible, but also the least complex, and requires the least effort of investment. SaaS solutions are applications or software that don’t require any installation or manual upgrading, and so the end user can be anyone. Many organizations use a combination of these solutions with the flexibility to change the service models used as their needs change.