第12章クラウドネイティブアプリケーション開発

• Cloud-based applications leverage cloud platforms; however, they do not take full advantage of the inherent characteristics of the cloud like cloud-native applications. Monoliths can be deployed in the cloud as cloud-based applications but can be converted to leverage a microservices architecture as cloud-native applications.

• Microservices are self-contained software units. Components were used before in older architectures such as web service components and SOA. However, the way components between these architectures communicate are quite different.

• There are several challenges associated with implementing a microservices architecture. Building microservices to interoperate with each other, as well as testing, debugging, versioning, deploying, logging, and monitoring microservices add additional challenges.

• Features of cloud-native applications include they are microservices-based, container-based, API-based, and are dynamically orchestrated to scale and optimize the use of computing resources.

• DevOps is a methodology that combines Agile software engineering and IT operations to release higher-quality software faster. CI/CD is a DevOps approach that provides steps to build, package, test, deploy, and release software components with the goal to automate as many steps as possible in the process.

• Some benefits of cloud-native applications are they are cost-effective, easily scalable, portable because they are containerized, reliable, and easier to manage through a DevOps pipeline using CI/CD.

• Best practices for creating cloud-native applications include automate as much of the development life cycle as possible, monitor the development environment as well as the use of microservices, document the services making it easier to integrate with them, and schedule incremental and reversible releases.

• Microservices are containerized. Docker is an open-source platform that creates, deploys, and manages microservices containers.

• Kubernetes is an open-source orchestration platform that is used for automating the deployment, scaling, and managing the health of microservices container-based workloads.

• There are various categories of tools that can be used to develop cloud-native applications, including IaC tools (e.g., Terraform), cloud-based DevOps platforms (e.g., GitLab, GitHub), containerization software products and platforms (e.g., Red Hat OpenShift), and developer tools to develop and deploy applications quickly (e.g., Tanzu, Node).

• There are three service models (IaaS, PaaS, and SaaS) and four deployment models (public cloud, private cloud, community cloud, and hybrid cloud) that make up the cloud computing model.

• Cloud service models (IaaS, PaaS, and SaaS) combine and change the way IT resources are consumed by cloud customers with the goal of providing a more economical solution as they can be scaled on-demand at a predictable cost. These cloud service models present a spectrum from complex and high effort of investment to simple and low effort of investment depending on business needs.

• Cloud deployment models (public cloud, private cloud, community cloud, and hybrid cloud) are where cloud services are implemented and made available to end users. Cloud computing deployments work on the principle of virtualizing compute resources. Cloud deployment models can be combined (e.g., hybrid clouds) to offer varying degrees of flexibility in terms of how cloud resources are accessed and managed.

• There are several cloud deployment options to choose from, including bare metal, VMs, unikernels, and containers that are offered in various cloud service models. Serverless computing is another cloud deployment option where developers can build and run applications in the cloud but are not responsible for provisioning, maintaining, and scaling the server infrastructure the application runs on.

• Given there are several cloud deployment technology options, an understanding of the use cases for these technologies can help customers choose the “best fit” options that satisfy business needs. For example, customers who need to have dedicated server with a high level of control would choose bare metal servers, whereas customers who need a solution with an immutable infrastructure would choose unikernels.

• Several tools are available for making implementing services using cloud deployment technologies easier. For example, IaC tools are useful to automate various steps in maintaining operating systems when adopting IaaS. In contrast, tools that automate software development process tasks are more suitable when adopting PaaS.

• There are some key considerations when selecting cloud deployment technologies, which include assessing whether cloud deployment technologies satisfy business needs, understand workload/service requirements, and ensuring they satisfy application and service requirements.

• Some things to consider when assessing whether cloud deployment technology options fit business needs are cost, architectural fit, performance, compliance, elasticity requirements, control requirements, and whether the cloud service provides lock-in.

• Cloud applications and services can be combined to form a cloud mashup. Cloud mashups can give organizations a competitive advantage by bringing competitive solutions to the market quickly.

• Some keys to successfully utilizing cloud deployment technologies include identifying currently available cloud deployment technologies and how they provide a fit to delivering cloud services, determining the use cases for these cloud deployment technologies and identifying tools available to help deliver cloud services, and assessing these cloud deployment technologies and selecting those that best fit business needs.