In the environment of application operation management, PaaS blurs the limitation of physical resources, and appears to the application as an on-demand, infinitely scalable virtual platform, as shown in Figure 1.
PaaS is the operating environment of cloud applications, and cloud applications obtain various (virtual) resources and capabilities required for operation through the programming interface API provided by PaaS. Generally speaking, resource acquisition is dynamic and timely. For example, the platform layer dynamically estimates the required computing and storage resources according to the load fluctuations of the application, and provides the required resources on demand according to the service quality agreement (SLA). From the perspective of automation, the basic goal of PaaS is to make applications more focused on the functional needs of users, while the platform automatically meets non-functional requirements and management needs such as load balancing and automatic scale adjustment for applications.
In traditional application development, developers need to spend a lot of energy and work on middleware selection, customization and deployment. On PaaS, this part of the work will be automatically completed by PaaS according to the needs and characteristics of the application. Users no longer need to manually select the Web container and database products they need, and select and expand the required management functions. Users are more concerned with the characteristics of the application, specifying and configuring application parameters such as runtime quality of service (QoS) requirements, scaling strategies, or deployment methods, and the platform layer can automatically provide software and hardware supporting the application according to the relevant configuration of the application Resources, as well as automatic load balancing, scaling control, and SLA optimization at runtime.
In short, the functional and structural design of PaaS mainly meets the needs of effectively and automatically managing a large number of applications.