Free Practice Questions for Alibaba Cloud ACA-Cloud1 Exam

 RDS for MySQL is a Platform as a Service (PaaS) product that provides a complete database solution on Alibaba Cloud. It is fully compatible with MySQL and supports various MySQL features, such as transactions, views, triggers, stored procedures, and functions. RDS for MySQL frees users from the tasks of managing the underlying operating system, runtime environment, and software packages. Users only need to focus on their business logic and data. Alibaba Cloud takes care of the database installation, configuration, backup, recovery, monitoring, scaling, and security. References: MySQL Database Concepts and Operations - Alibaba Cloud Academy, Alibaba RDS Course | Cloud Academy, ACA Cloud Computing Certification - Alibaba Cloud Academy

Server Load Balancer (SLB) is a ready-to-use service that seamlessly integrates with Elastic Compute Service (ECS) to manage varying traffic levels without manual intervention. SLB distributes incoming traffic among multiple ECS instances according to the configured forwarding rules, increasing the service capabilities and fault tolerance of your applications1. SLB supports Layer-4 (TCP/UDP) and Layer-7 (HTTP/HTTPS) load balancing, health checks, session persistence, cross-zone disaster recovery, and other advanced features2.

References: 1: Alibaba Cloud Academy, “Server Load Balancer”, https://edu.alibabacloud.com/elearning/lesson/ACA-Cloud-Computing-Certification/lesson-4-server-load-balancer  2: Alibaba Cloud, “What is Server Load Balancer?”, https://www.alibabacloud.com/help/doc-detail/27539.htm

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

 The issue that Company B faces is that their music files stored in OSS are being downloaded by unauthorized users who access them through search engines, rather than through their website. This is called leeching, which is a form of bandwidth theft that consumes the OSS traffic and increases the cost for Company B. To address this issue, Company B can limit the access sources by configuring the “Anti-leech settings” of OSS bucket attributes. Anti-leech settings allow the bucket owner to specify a referer whitelist, which is a list of domain names that are allowed to access the OSS resources. The referer is a part of the HTTP header that indicates the source URL of the request. By setting a referer whitelist, Company B can prevent leeches from accessing their music files directly from search engines or other websites, and only allow access from their own website domain name. This way, Company B can protect their OSS resources from unauthorized access and reduce their OSS traffic costs. The other options are not effective or relevant for addressing the issue. Migrating music files from OSS to data disks for ECS instances would increase the storage and computing costs for Company B, and also reduce the scalability and availability of their music files. Changing the website access mode to HTTPS would enhance the security and encryption of the website, but it would not prevent leeches from accessing the OSS resources through search engines. Introducing SLB for extra protection would improve the load balancing and high availability of the ECS instances, but it would not affect the access control of the OSS resources. References: OSS Anti-Leech Referer Configuration and Error Elimination

 According to the Alibaba Cloud Academy, Alibaba Cloud Object Storage Service (OSS) is a massive, highly available, secured and cost effective storage service. OSS is superior than self-built storage in all these aspects. One of the advantages of OSS is its high availability, which means that the data stored in OSS can be accessed anytime and anywhere with minimal downtime or interruption. OSS achieves high availability by ensuring data reliability of not less than 99.99999999%. Data reliability is the probability that the data stored in OSS is not lost or corrupted. OSS ensures data reliability by automatically backing up data with multiple redundant copies across different devices and facilities. Therefore, the option B is the correct answer that relates to the high availability of OSS. References: What is OSS? - Alibaba Object Storage Service Course - Cloud Academy, [Object Storage Service(OSS): Store Data Safely In The Cloud - Alibaba Cloud Blog]

The main purpose of DDoS attack is to make the target server unable to provide service normally, which is one of the network attacks that are most difficult to defend. Comprehensive and Detailed Explanation: A Distributed Denial-of-Service (DDoS) attack is a malicious attempt to disrupt the normal operation of a target server, service, or network by overwhelming it with a flood of internet traffic from multiple sources1. The main purpose of a DDoS attack is to make the target server unable to provide service normally, which is one of the network attacks that are most difficult to defend. A DDoS attack can cause serious damage to the availability, performance, and reputation of the target server, service, or network, and result in significant financial losses and customer dissatisfaction2.

The other options are not accurate descriptions of a DDoS attack. The main target for a DDoS attack is not the database, but the server, service, or network that hosts the database or other applications. A DDoS attack will not try to crack the password through a large number of attempts, but rather try to exhaust the resources of the target server, service, or network. The purpose of a DDoS attack is not to steal confidential information, but rather to disrupt the normal operation of the target server, service, or network. References: 1: What is a DDoS Attack?1 2: Anti-DDoS: Intelligent DDoS Protection Service - Alibaba Cloud2

 According to the Alibaba Cloud Academy, Alibaba Cloud provides powerful security services that are the same level of security services used to support Alibaba Group’s Double 11 Shopping Festival. However, you do not have to pay first before using any of the security services. Alibaba Cloud offers some security services for free, such as Anti-DDoS Basic, Server Guard, and Security Center Basic Edition. Other security services, such as Anti-DDoS Pro, WAF, and Security Center Enterprise Edition, are charged based on different billing methods, such as subscription, pay-as-you-go, or traffic-based. Therefore, the statement is false. References: Alibaba Cloud Security Services - Alibaba Cloud Security Course - Cloud Academy, Alibaba Cloud Security Pricing - Alibaba Cloud

ApsaraDB RDS for MySQL is a cloud-based relational database service that provides secure, cost-effective, and scalable database solutions for various applications. RDS for MySQL supports creating read-only instances that are synchronized with the primary instance in real time. Read-only instances can handle read requests from applications and reduce the read pressure on the primary instance. This can improve the performance and availability of the database system. Read-only instances can also be used for scenarios such as report analysis, data backup, and disaster recovery.

References:

Overview of read-only ApsaraDB RDS for MySQL instances

ACA Cloud Computing Certification Exam Preparation Course

Alibaba Cloud Computing Exam Question 2022

 An ECS image is a copy of data from one or more disks that are attached to an ECS instance. You cannot retrieve data directly from an ECS image and use it right away. You need to create an ECS instance from the image first, and then access the data on the disks of the instance. References: Elastic Compute Service:Image overview