Hi, everyone. Welcome to the first chapter in our Tencent Cloud Solutions Architect Professional Course, Enterprise Cloud. At the end of this chapter, you'll be able to understand the basic principles of architecture design, the basic scenarios of Cloud architecture design, and the services and solutions related to the common use cases of the enterprise Cloud. In this chapter, we'll cover three sections : Principles of Cloud Architecture Design, General Scenarios of Cloud Architecture Design, and Mappings Between General Scenarios and Services. This video will cover the first section, Principles of Cloud Architecture Design. Subsequent videos will cover the remaining two sections. Let's get started with Section 1, Principles of Cloud Architecture Design. In this video, we'll cover the significance of Cloud architecture design, Cloud architecture for high availability, Cloud architecture for high scalability, Cloud architecture for high security, and design for cost optimization. The purposes of Cloud architecture design are to select and combine Tencent Cloud services at reasonable costs to improve the availability, scalability, and security of the system while satisfying the customer's business needs. Cloud architecture for high availability includes Cloud load balancers, cross datacenter network infrastructure, autoscaling, and serverless Cloud functions. For CLBs, you typically want to implement redundancy designed to avoid single points of failure. High available network infrastructure is the basis of Cloud networking, which, in addition to autoscaling, creates the architecture framework that drives powerful application hosting. Furthermore, the addition of SCFs enables easy code execution and microsegmentation to deliver modern application infrastructure. Let's look at Cloud architecture for high scalability and the benefits of a loosely coupled architecture. Now, generally speaking, modularization reduces the failure scope, meaning that if one module fails, the normal operations of the other modules won't be affected, allowing the overall application to still function. Additionally, upgrade costs are reduced as inserting a new module would not affect the rest of the application. For instance, a message queue is an excellent way to decouple the architecture using simultaneous read and write processes that don't interfere with each other. Tencent Elastic Microservice, TEM, is a product that provides an application-wide lifecycle management platform for applications and microservices. TEM can integrate microservices ecosystems to multiple Tencent Cloud environments, segmenting the selected components. Another service which helps deliver loosely coupled architectures is the API Gateway, which provides a full API hosting service that helps developers to easily manage the entire lifecycle of API creation, maintenance, and release monitoring. Now let's look at Cloud architecture for high security. Host security, network security, and infrastructure security are all levels of physical security that fall under the responsibility of the Cloud vendor. Here we can also include topics such as data security, which includes redundancies, backups, and recovery protocols that protect stored data, prevent data loss or data leakages, and ensure the integrity of data. On a different layer, application security incorporates secure design, ensuring the security of deployment and operations. Security operations are needed to protect and maintain the security of applications, including external facing defenses, such as web application firewalls and continuous assessments of vulnerabilities. Another level up is the business security, which is defined by the concept of business continuity, ensuring that business applications can continue running even in case of a disaster or failure. Tencent Cloud designed for cost optimization reduces investments in resources for clarification, allowing customers to greatly reduce their total cost ownership and allowing them to focus on their business and core competencies. This includes reduced labor costs for management, development, operations, and infrastructure costs such as IDC, hardware, and network equipment costs. Additional time costs that could be reduced include IDC site selection, service provider selection, business negotiations, equipment commissioning, and test runs.