Free Practice Questions for Alibaba Cloud ACA-Cloud1 Exam

According to the Alibaba Cloud Academy, Auto Scaling is a service that automatically creates and releases ECS instances based on pre-defined rules in order to scale services to match demand. Furthermore, it can configure server load balancer and relational database service white lists, without any manual intervention. Therefore, when ECS is used with Auto Scaling, the number of ECS instances is automatically adjusted based on traffic. References: Introduction to Alibaba Auto Scaling - Cloud Academy, ACA Cloud Computing Exam Preparation Course - Alibaba Cloud, Module 4: Cloud Computing Elasticity, Lesson 1: Auto Scaling, Slide 2.

ECS instance filesystem directory operation is not a supported method to create a bucket in OSS. A bucket is a container for objects in OSS, and it is not related to the filesystem of an ECS instance. To create a bucket in OSS, you can use one of the following methods1:

through OSS API/SDK: You can use the OSS API or SDK to call the PutBucket operation to create a bucket. The OSS API and SDK support various programming languages, such as Java, Python, PHP, C#, and Node.js2.

through oss cmd tool: You can use the oss cmd tool, which is a command-line tool based on the OSS SDK for Python, to create a bucket by using the ossutil mb command3.

through cloud console: You can use the Alibaba Cloud console to create a bucket by following the steps in the documentation4. References: 1: Create buckets - Object Storage Service - Alibaba Cloud Documentation Center2: PutBucket - API Reference| Alibaba Cloud Documentation Center3: Create a bucket - OSSUTIL User Guide| Alibaba Cloud Documentation Center4: Create a bucket - Object Storage Service - Alibaba Cloud Documentation Center.

 Web Application Firewall (WAF) is a cloud-based security service that protects web applications from common web attacks, such as SQL injection, cross-site scripting, and HTTP flood. WAF can also filter out malicious requests and bots, and ensure that only legitimate traffic reaches the web servers. WAF can help online shops to avoid HTTP flood attacks and ensure only genuine customers joining the event.

References:

Alibaba Cloud Web Application Firewall

ACA Cloud Computing Certification Exam Preparation Course

Alibaba Cloud Computing Exam Question 2022

After adding your website to the WAF protection list, you can enable HTTP Flood protection and select an appropriate protection mode for the website

An ICP license is a permit issued by the Chinese Ministry of Industry and Information Technology (MIIT) that allows websites to operate in China. An ICP license is required for any website that is hosted on a mainland China server, or that wants to use a China-based CDN service to accelerate its access in China. Therefore, you would need to apply an ICP license in the following cases:

Accelerate your Overseas Website in China: If you have a website that is hosted outside of China, but you want to use Alibaba Cloud’s CDN service to improve its performance and user experience in China, you would need to apply an ICP license for your domain name. This is because Alibaba Cloud’s CDN nodes are located in mainland China, and any website that uses them must comply with the Chinese regulations.

Launch your website in China: If you want to host your website on an Alibaba Cloud ECS instance or OSS bucket that is located in mainland China, you would need to apply an ICP license for your domain name. This is because any website that is hosted on a mainland China server must have an ICP license to be accessible and legal in China.

Launch your online shop in China: If you want to run an e-commerce website that sells goods or services to customers in China, you would need to apply an ICP license for your domain name. This is because any website that engages in commercial activities in China must have an ICP license to operate legally and securely in China.

References: What is an ICP License? - Alibaba Cloud Academy, ICP License Application - Alibaba Cloud Documentation Center

When using Alibaba Cloud OSS, you can set access control in three different levels, which are bucket level, object level, and RAM account level. Bucket level access control is the highest level of access control, which determines whether a user can access the bucket and its objects. Bucket level access control can be set to public read/write, public read, or private. Object level access control is the second level of access control, which determines whether a user can access a specific object in the bucket. Object level access control can be set to inherit from the bucket, public read/write, public read, or private. RAM account level access control is the lowest level of access control, which determines whether a user can perform certain operations on the bucket or the object. RAM account level access control can be set by using RAM policies, which specify the actions, resources, and conditions for the access. References: Object Storage Service (OSS) - Alibaba Cloud Academy, Access Control - Alibaba Cloud Documentation Center

 ApsaraDB RDS is a cloud-based relational database service that provides secure, cost-effective, and scalable database solutions for various applications. RDS has many advantages over self-built databases, such as high availability, automatic backup, and easy O&M. One of the statements that is wrong when comparing RDS with self-built database is that self-built database supports quick deployment and elastic scaling. This is not true, because self-built database requires users to purchase, install, and configure hardware and software by themselves, which can be time-consuming and complex. Moreover, self-built database cannot easily adjust the computing and storage resources according to the business needs, which can lead to over-provisioning or under-provisioning. RDS, on the other hand, supports quick deployment and elastic scaling, because users can create, modify, or delete RDS instances in minutes through the console or API. Users can also scale up or down the RDS instance specifications, storage capacity, or network bandwidth without affecting the business continuity.

References:

ApsaraDB RDS

ACA Cloud Computing Certification Exam Preparation Course

Which of the following statements is NOT correct, when comparing RDS …

 Server Load Balancer (SLB) can help protect from distributed denial-of-service (DDoS) attacks by distributing network traffic across groups of backend servers to improve the service capability and application availability. SLB also supports built-in Anti-DDoS services to ensure business security. Anti-DDoS services can mitigate DDoS attacks at the Tbit/s level and provide multiple defense methods, such as blackhole filtering, traffic scrubbing, and access control1. In addition, you can integrate Application Load Balancer (ALB) with Web Application Firewall (WAF) in the console to ensure security at the application layer and prevent attacks such as SQL injection2. References: 1: Server Load Balancer(SLB) - Alibaba Cloud2: Associate an EIP protected by Anti-DDoS Pro/Premium with an ALB instance - Server Load Balancer - Alibaba Cloud Documentation Center.

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.

Auto Scaling is a management service that can automatically adjust elastic computing resources based on your business needs and policies. It can help you cope with traffic spikes, reduce costs, and improve service availability1. Auto Scaling supports adding an existing ECS instance into the scaling group, which is a collection of ECS instances that share the same scaling configuration and scaling rules2. However, the existing ECS instance must meet certain requirements, one of which is that the instance and the scaling group must be in the same region3. A region is a physical location where Alibaba Cloud deploys its data centers. Each region consists of multiple isolated zones that have independent power grids and networks4. Therefore, the instance and the scaling group do not have to be in the same zone, as long as they are in the same region.

References: 1: Alibaba Cloud Academy, “Auto Scaling”, https://edu.alibabacloud.com/elearning/lesson/ACA-Cloud-Computing-Certification/lesson-6-auto-scaling  2: Alibaba Cloud, “Scaling group”, https://www.alibabacloud.com/help/doc-detail/25948.htm  3: Alibaba Cloud, “Add an existing ECS instance to a scaling group”, https://www.alibabacloud.com/help/doc-detail/25949.htm  4: Alibaba Cloud, “Regions and zones”, https://www.alibabacloud.com/help/doc-detail/40654.htm

You can upgrade or downgrade an ECS instance’s configuration to meet your business needs. Upgrading an instance’s configuration means increasing the vCPUs, memory, bandwidth, or disk capacity of the instance. Downgrading an instance’s configuration means decreasing the vCPUs, memory, bandwidth, or disk capacity of the instance. You can change the configuration of an ECS instance by using one of the following methods1:

Change the instance type: You can change the instance type of an ECS instance to adjust the vCPUs and memory of the instance. You can change the instance type of an ECS instance in the following scenarios2:

The instance is in the Stopped state and uses a pay-as-you-go billing method.

The instance is in the Running state and uses a subscription billing method, and the new instance type belongs to the same instance family as the original instance type.

Change the bandwidth configuration: You can change the bandwidth configuration of an ECS instance to adjust the network performance of the instance. You can change the bandwidth configuration of an ECS instance in the following scenarios3:

The instance is in the Stopped state and uses a pay-as-you-go billing method, and the instance is not associated with an EIP.

The instance is in the Running state and uses a subscription billing method, and the instance is not associated with an EIP.

Change the system disk or data disk: You can change the system disk or data disk of an ECS instance to adjust the disk capacity or performance of the instance. You can change the system disk or data disk of an ECS instance in the following scenarios4:

The instance is in the Stopped state and uses a pay-as-you-go billing method, and the disk is not encrypted.

The instance is in the Running state and uses a subscription billing method, and the disk is not encrypted. References: 1: Overview of instance configuration changes - Alibaba Cloud2: Change the instance type of an ECS instance - Alibaba Cloud3: Change the bandwidth configuration of an ECS instance - Alibaba Cloud4: Change the system disk or data disk of an ECS instance - Alibaba Cloud.