2.1 Overview
2.2 Distributed system architecture
2.3 Web development technology mode
2.4 Message Queuing Technology
2.5 Virtualization technology
2.6 Distributed storage technology
2.7 High-performance cross-platform GIS technology
2.8 Multi-level intelligent cluster technology
2.9 GIS microservice multi-process technology
2.10 Multithreading and Parallel Spatial Analysis Technology
2.11 Summary of this chapter
>>2.1 Overview
What is cloud GIS? What is the difference between cloud GIS and traditional GIS? These are two questions that GIS users often raise when establishing cloud GIS projects. Some people think that cloud GIS=virtualization technology. Putting GIS software on Docker and other distributed hosting cluster deployment is the end. This may be a "shortcut", but it is difficult to use the technical advantages of cloud GIS.
How does a real cloud GIS application work? The cloud GIS system can quickly provide development environments, test environments and production environments for different operating systems and different GIS platforms, and supports the rapid launch of GIS projects and the flexible configuration of resources; when the cloud GIS system detects that a host host is overloaded, it Automate the dynamic migration of virtual machines to achieve load balancing; when a certain service of the GIS application has a problem, you can directly delete the virtual machine that supports the service, and then create a new instance through the prefabricated image and automatically carry the service capacity; if it is required for the cloud The GIS application adds a new function, and any team can use the programming language that they are good at to provide support; if there is a serious problem when using the GIS application, the engineer can quickly narrow the scope, and then locate the problem, analyze the problem and solve the problem according to the rich log; If a GIS map service is under too much pressure, the system will automatically increase the cluster nodes to share the pressure; operation and maintenance personnel can easily manage a dozen host servers or dozens of virtual machines.
As shown in Figure 2-1, the architecture design and development model of the cloud GIS system are fundamentally different from the technical route of traditional projects. At the same time, these technologies will be applied to different service category layers (IAAS, PAAS, SAAS).
Take the open source basic cloud platform OpenStack as an example. Through the source code research of the OpenStack project, it can be seen that the OpenStack project is completed by multiple components. Each component is composed of different services. Different components and different services of the same component are all It can be distributed in different physical environments, and at the same time, it supports the greater access pressure of cluster technology. Components and components and services within components are all messaged through messages, and each component and its service provides a RESTful API. Therefore, the distributed architecture design of the basic cloud platform and the RESTful interface design provide the technical characteristics of the cloud platform's elastic scaling and dynamic migration.