Alibaba Cloud ACA-Cloud1 - ACA Cloud Computing Associate

Alibaba Cloud Auto Scaling service allows you to automatically adjust the number of ECS instances in a scaling group based on your business needs and scaling policies. You can set the minimum and maximum number of instances in a scaling group to limit the range of scaling actions1. When you create a scaling rule, you can specify the number of instances to be added or removed, or the expected number of instances after the scaling action2. You can also create a scheduled task to execute a scaling rule at a specified time or periodically3.

In this question, the customer sets the minimum number of instances to 6 and the maximum number of instances to 8 in the scaling group. This means that the scaling group will always have at least 6 instances and at most 8 instances. The customer also adds a scaling rule to remove 5 instances, and creates a scheduled task based on this rule. However, this scaling rule will not be executed if it violates the minimum and maximum limits of the scaling group. Therefore, when the scheduled task is activated once, the scaling group will only remove 2 instances, which is the difference between the current number of instances (8) and the minimum number of instances (6). The remaining number of instances in the scaling group will be 6, which is the correct answer. References: 1: Create a scaling group - Auto Scaling - Alibaba Cloud Documentation Center2: Create a scaling rule - Auto Scaling - Alibaba Cloud Documentation Center3: Create a scheduled task - Auto Scaling - Alibaba Cloud Documentation Center.

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Explanation

Alibaba Cloud China Connect is a service that can help international companies do business in China by providing them with the necessary infrastructure, compliance, and ecosystem support1. China Connect includes the following services1:

ICP Support: Alibaba Cloud helps you obtain the Internet Content Provider (ICP) license, which is required for any website hosted in mainland China.

Office registration support: Alibaba Cloud helps you register a legal entity in mainland China, which is required for some business scenarios such as e-commerce, online payment, and social media.

Connect your service with Alibaba Group ecosystem: Alibaba Cloud helps you leverage the Alibaba Group ecosystem, which includes platforms such as Taobao, Tmall, Alipay, and DingTalk, to reach millions of potential customers and partners in China.

However, China Connect does not include web hosting, which is a service that allows you to store and deliver your website content on Alibaba Cloud servers. Web hosting is a separate service that you can purchase from Alibaba Cloud, and it is not part of China Connect.

References: 1: Alibaba Cloud, “China Connect”, https://www.alibabacloud.com/chinaconnect

Alibaba Cloud relational database service (RDS) is a stable, reliable and elastic online database service that supports various database engines, such as MySQL, SQL Server, PostgreSQL, MariaDB, and PPAS (PostgreSQL with Oracle compatibility)1. RDS provides high availability, backup and recovery, security, and monitoring features for your databases. RDS does not support Oracle database, which is a proprietary database system developed by Oracle Corporation2. If you need to use Oracle database on Alibaba Cloud, you can deploy it on an ECS instance or use the Oracle Database Backup Service3.

References: 1: Alibaba Cloud Academy, “RDS Concepts”, https://edu.alibabacloud.com/elearning/lesson/ACA-Cloud-Computing-Certification/lesson-5-rds-concepts  2: Oracle, “Oracle Database”, https://www.oracle.com/database/  3: Alibaba Cloud, “Oracle Database Backup Service”, https://www.alibabacloud.com/product/oracle-database-backup-service

 According to the Alibaba Cloud Academy, Alibaba Cloud’s object storage service (OSS) is a cloud storage service that enables you to store, backup, and archive any amount of data in the cloud. OSS is a cost-effective, highly secure, and highly reliable cloud storage solution. The capacity of each bucket is unlimited, and there is no limit on the number of files in a single bucket. Therefore, the statement is false. References: What is OSS? - Alibaba Object Storage Service Course - Cloud Academy, Object Storage Service(OSS): Store Data Safely In The Cloud - Alibaba Cloud Blog

 According to the Alibaba Cloud Academy, business record filing is a process of registering your website information with the provincial communication management bureau where your server is located. The approval requirements for business record filing vary depending on provincial communication management bureaus. Some provinces may require additional materials or procedures for business record filing. Therefore, the statement is true. References: ACA Cloud Computing Exam Preparation Course - Alibaba Cloud, Module 2: Cloud Computing Security, Lesson 2: Business Record Filing, Slide 3.

A large shopping mall deploys a new video surveillance system. The five-floor building in which the mall is located installed 35 HD cameras to monitor the major exits. The surveillance system is deployed on an ECS instance, which has four 2 TB data disks to store video data.

However, video data grows rapidly and the engineers find that the ECS will run out of storage space within 2 weeks.

In this case, OSS is thought to be the best solution for addressing the storage challenge while ensuring quick access to historical video data when needed. OSS is a cloud-based object storage service that provides massive, secure, low-cost, and highly reliable storage for unstructured data such as images, videos, and documents. OSS can store any amount of data and scale up or down on demand. OSS also supports direct video stream storage capabilities, removing the need for a video segmentation cluster. OSS can be accessed through RESTful APIs, SDKs, or web consoles, and can be integrated with other Alibaba Cloud services such as CDN, ECS, and SLB. OSS provides various storage classes for different data storage scenarios, from hot data storage to cold data storage. For video surveillance data, the Infrequent Access (IA) or Archive storage classes can be used to reduce the storage cost while maintaining high data durability and availability123. References: 1: Alibaba Cloud Multimedia Solutions | Video Monitoring & Surveillance1 2: Overview - Object Storage Service - Alibaba Cloud2 3: OSS Concepts - Alibaba Object Storage Service Course - Cloud Academy

 A company wants to use Alibaba Cloud service to replace their self-built database, which of the following services should it choose? The best answer is ApsaraDB for RDS, which is a stable, reliable, cost-effective, and scalable online database service that supports most mainstream database engines, including MySQL, SQL Server, PostgreSQL, PPAS (highly compatible with Oracle), and MariaDB1. ApsaraDB for RDS is based on the Apsara Distributed File System and high-performance SSDs of Alibaba Cloud, and provides various features such as backup and recovery, performance monitoring, security, and disaster recovery2. By using ApsaraDB for RDS, the company can reduce the complexity and cost of database management, and focus on their core business.

The other options are not suitable for replacing a self-built database. Server Load Balancer (SLB) is a service that distributes traffic among multiple ECS instances according to the configured forwarding rules. It can be used to balance the load and improve the service availability and fault tolerance of applications3. Alibaba Cloud CDN (Content Delivery Network) is a service that delivers content from origin servers to edge nodes, and accelerates the response to user requests. It can be used to improve the user experience and reduce the bandwidth consumption of origin servers4. Deploying more ECS instances is a way to increase the computing resources and scalability of applications, but it does not provide a database service5. References: 1: What is ApsaraDB RDS? - ApsaraDB RDS - Alibaba Cloud1 2: ApsaraDB RDS:What is ApsaraDB RDS? - Alibaba Cloud2 3: Server Load Balancer - Alibaba Cloud Documentation Center3 4: Alibaba Cloud CDN - Alibaba Cloud4 5: Elastic Compute Service (ECS) - Alibaba Cloud5

 B is the correct answer because Auto Scaling can automatically remove unhealthy ECS instances from the scaling group, and also automatically add equivalent amount of new ECS instances back to the scaling group. This feature is called Elastic Self-Health, and it can improve the availability and reliability of the scaling group. Elastic Self-Health can be enabled or disabled in the scaling group settings. When Elastic Self-Health is enabled, Auto Scaling monitors the health status of the ECS instances in the scaling group based on the health check results of the Server Load Balancer (SLB) instances that are associated with the scaling group. If an ECS instance is detected as unhealthy by SLB for a specified period of time, Auto Scaling removes the unhealthy ECS instance from the scaling group and releases it. Then, Auto Scaling triggers a scale-out event to add a new ECS instance to the scaling group to maintain the desired capacity12 References: 1: Elastic Self-Health 2: Enable or disable Elastic Self-Health

Alibaba Cloud does not support intranet communication between products that are not in the same region, which means that ECS instances in different regions cannot communicate with each other on the intranet, and ECS instances and other products in different regions, such as ApsaraDB for RDS and OSS instances, cannot communicate with each other on the intranet. However, this does not mean that Server Load Balancer cannot be deployed for ECS instances in various regions. Server Load Balancer is a service that distributes traffic among multiple ECS instances according to the configured forwarding rules. It can be used to balance the load and improve the service availability and fault tolerance of applications. Server Load Balancer supports cross-region deployment, which means that it can distribute traffic to ECS instances in different regions12. References: 1: ACA Cloud Computing Exam Preparation Course - Alibaba Cloud3 2: Server Load Balancer - Alibaba Cloud Documentation Center4

Domain name binding is a feature that allows you to use your own domain name to access your OSS bucket, instead of using the default OSS domain name. Domain name binding has the following requirements and limitations12:

Your customized domain name will be audited by Alibaba Cloud. You need to submit a domain name binding request and wait for approval before you can use your own domain name to access your OSS bucket.

Your customized domain name need to be put on record in MIIT (Ministry of Industry and Information Technology). This is a mandatory requirement for all websites that are hosted in mainland China. You need to provide your domain name information and relevant documents to MIIT and obtain an ICP filing number before you can use your own domain name to access your OSS bucket.