Pass the Alibaba Cloud Alibaba Cloud Computing ACA-Cloud1 Questions and answers with CertsForce

 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.

 D is the correct answer because OSS supports 3 internal data copies, no human intervention is required to recover the data when anything goes wrong. OSS provides high data reliability and durability by storing multiple replicas of data on different devices in the same region. OSS automatically detects and repairs data errors or failures, and ensures data consistency across all replicas. OSS also supports cross-region replication (CRR) to back up data to another region for disaster recovery12

A, B, and C are incorrect answers because they do not reflect the actual backup technology and policies of OSS.

A is incorrect because OSS does not require manual recovery of data, as it automatically handles data errors or failures.

B is incorrect because OSS provides data protection and backup for customers, and customers do not need to safeguard their own data or use offsite backups.

C is incorrect because OSS does not use RAID0+1 configuration of its underlying physical hard disks, but rather uses a distributed storage system that stores multiple replicas of data on different devices.

References: 1: OSS Overview 2: OSS Backup

 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

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

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

Using a cloud computing service is simple and straightforward. One can choose the instance with desired specification, finish payment and then use it right away. Moreover, the underlying physical machines are managed by cloud service providers and transparent to users. This is the basic concept of cloud computing, which provides on-demand, scalable, and reliable computing resources and services over the internet12. References: 1: ACA Cloud Computing Exam Preparation Course - Alibaba Cloud3 2: What Is Alibaba Cloud Academy Certification?4

Alibaba Cloud provides security services for the underlying hardware of cloud computing, such as physical security, network security, host security, and storage security. Alibaba Cloud also provides security isolation between cloud computing tenants, such as virtualization isolation, network isolation, and data isolation. These security services are part of Alibaba Cloud’s shared responsibility model, where Alibaba Cloud is responsible for the security of the cloud infrastructure, while customers are responsible for the security of their applications and data on the cloud. References: Alibaba Cloud Security Services, Alibaba Cloud Security & Compliance Center, Shared Responsibility Model

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.

According to the Alibaba Cloud Academy, Alibaba Cloud OSS is a cloud storage service that features massive capacity, outstanding security, low cost, and high reliability. To control the access to the files stored on OSS, OSS provides multiple access permissions for each bucket. These bucket permissions are:

Public-read-write: Anyone, including anonymous users, can perform read and write operations on the objects in the bucket. The owner of the bucket is charged for the requests and traffic generated by these operations. This permission poses a high security risk and is not recommended.

Public-read: Only the owner of the bucket and authorized RAM users can perform write operations on the objects in the bucket. Anyone, including anonymous users, can perform read operations on the objects in the bucket. The owner of the bucket is charged for the requests and traffic generated by these operations.

Private: Only the owner of the bucket and authorized RAM users can perform read and write operations on the objects in the bucket. Other users, including anonymous users, are denied access to the objects in the bucket unless they have been granted temporary access permissions by the bucket owner or authorized RAM users.

Therefore, the options B, C, and D are the correct answers that describe the bucket permissions in OSS. References: OSS Security - Alibaba Object Storage Service Course - Cloud Academy, OSS Concepts - Alibaba Cloud Documentation Center

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