ACA-Cloud1 Practice Exam Questions with Answers ACA Cloud Computing Associate Certification

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

RDS (Relational Database Service) is a fully managed online database service that supports various database engines, such as MySQL, SQL Server, PostgreSQL, MariaDB, and PPAS (PostgreSQL with Oracle compatibility)1. However, 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

 A is the correct answer because Server Load Balancer (SLB) can manage sudden spikes in traffic, minimize response time and maintain 99.99% availability of your web application. SLB distributes network traffic across groups of backend servers to improve the service capability and application availability. It includes Layer 4 Network Load Balancer (NLB), Layer 7 Application Load Balancer (ALB), and Classic Load Balancer (CLB). SLB provides high-performance load balancing services with super four-seven processing capabilities. SLB also provides disaster recovery at four levels for high availability and supports built-in Anti-DDoS services to ensure business security. SLB supports multiple protocols, such as TCP, UDP, HTTP, HTTPS, QUIC, and gRPC. SLB also supports cloud-native networks and is integrated with other cloud-native services, such as Container Service for Kubernetes (ACK), Serverless App Engine (SAE), and Kubernetes123 References: 1: SLB Overview 2: SLB Types & Pricing 3: What is ALB?

Manage sudden spikes in traffic, minimize response time and maintain 99.99% availability of your web application with Server Load Balancer.

 Alibaba Cloud CDN can directly accelerate the access to the files stored in OSS and reduce OSS traffic costs. Alibaba Cloud CDN is a global network of points of presence (POPs) that are distributed across the globe. Alibaba Cloud CDN serves to reduce back-to-origin traffic. This in turn prevents network congestion and reduces latency. If you use Alibaba Cloud CDN to accelerate access to OSS, you can benefit from the following advantages1:

• Improved user experience: Alibaba Cloud CDN caches the files stored in OSS to the POPs that are nearest to the users. This reduces the distance that the files need to travel and improves the access speed and user experience.
• Reduced OSS traffic costs: Alibaba Cloud CDN reduces the number of requests that are sent to OSS. This reduces the OSS traffic costs and the load on the OSS servers.
• Enhanced security: Alibaba Cloud CDN supports HTTPS secure acceleration and anti-leech protection. This ensures the security and integrity of the files stored in OSS. References: Use Alibaba Cloud CDN to accelerate access to OSS

According to the Alibaba Cloud Academy, a cloud disk snapshot is a point-in-time backup of a cloud disk. You can use snapshots to back up data, create images, or restore data. The operations that you can do on a cloud disk snapshot are snapshot creation, snapshot deletion, snapshot rollback, and snapshot sharing. Snapshot duplicate and snapshot download are not the operations that you can do on a cloud disk snapshot. Therefore, the options A and C are the correct answers. References: Snapshot Overview - Alibaba Cloud Documentation Center, ACA Cloud Computing Exam Preparation Course - Alibaba Cloud, Module 3: Cloud Computing Storage, Lesson 2: Snapshot, Slide 2

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

Server Load Balancer (SLB) is a service that distributes traffic among multiple ECS instances to improve the service capabilities of applications. SLB monitors the health of ECS instances in real time and automatically isolates unhealthy instances from the server pool according to the configured health check policy. This ensures that the traffic is only forwarded to healthy instances, thereby improving the availability and fault tolerance of applications. References: ACA Cloud Computing Certification - Alibaba Cloud Academy, E-Learning Courses - Alibaba Cloud Academy, Server Load Balancer - Alibaba Cloud Documentation Center

Server Load Balancer (SLB) is a service that distributes network traffic across multiple ECS instances to improve the service capabilities of applications. By using SLB, you can increase the availability and fault tolerance of your applications. You can also use SLB with Auto Scaling to dynamically adjust the number of ECS instances based on the traffic load. Multiple lower-configuration I/O-optimized ECS instances can be used with SLB to deliver a high-availability architecture that can handle traffic spikes and reduce costs.

References:

• Alibaba Cloud Server Load Balancer
• Alibaba Cloud Elastic Compute Service
• ACA Cloud Computing Certification Exam Preparation Course

Alibaba Cloud provides anti-DDoS products of different levels to protect your applications and data from DDoS attacks. Among them, Anti-DDoS Service Pro is the most suitable product for ensuring high service availability under DDoS attacks. Anti-DDoS Service Pro is a proxy-based mitigation service that diverts network traffic to the Alibaba Cloud global anti-DDoS network through DNS resolution, mitigates volumetric DDoS attacks and resource exhaustion DDoS attacks, and ensures the stability and availability of your origin servers1. Anti-DDoS Service Pro provides the following features and benefits2:

• Over 10 Tbit/s mitigation capacity: Anti-DDoS Service Pro can defend against large-scale DDoS attacks at the Tbit/s level and ensure high service availability.
• AI-enabled for mitigating sophisticated attacks: Anti-DDoS Service Pro can automatically detect and mitigate sophisticated DDoS attacks, such as HTTP flood, HTTPS flood, and DNS flood, and quickly adjust protection policies based on the attack characteristics.
• Hiding origin server IPs: Anti-DDoS Service Pro can hide the IP addresses of your origin servers and prevent attackers from bypassing the proxy and directly attacking your origin servers.
• Multiple protection modes: Anti-DDoS Service Pro supports normal protection mode, emergency protection mode, and always-on protection mode, which can be switched based on your business needs and risk levels.
• Comprehensive security reports: Anti-DDoS Service Pro provides comprehensive security reports that display the attack details, protection status, and traffic statistics of your protected domains. References: 1: Anti-DDoS: Intelligent DDoS Protection Service - Alibaba Cloud2: Anti-DDoS Pro and Anti-DDoS Premium features - Anti-DDoS Pro and Anti-DDoS Premium - Alibaba Cloud Documentation Center.

Server Guard is a cloud-based security service that provides real-time protection for servers against intrusion events, such as brute force password cracking. Server Guard consists of a lightweight agent that is installed on the server and a cloud protection center that analyzes and responds to security threats. Server Guard can help the administrator to reduce the possibility of brute force password cracking by providing the following features1:

• Password cracking protection: Server Guard can detect and block password cracking attempts on servers, such as SSH brute force attacks on Linux servers and RDP brute force attacks on Windows servers. Server Guard can also alert the administrator of the attack source, time, and frequency, and provide suggestions for password strengthening.
• Webshell detection and removal: Server Guard can scan and remove webshells that are maliciously implanted on servers by hackers. Webshells are scripts that allow hackers to remotely execute commands on servers, such as stealing data, uploading files, or launching attacks. Server Guard can identify and delete webshells based on signature matching, behavior analysis, and machine learning.
• Anti-virus and anti-ransomware: Server Guard can detect and terminate various types of malware, such as ransomware, mining programs, backdoor programs, worms, and trojans. Server Guard can also prevent the encryption and deletion of files by ransomware, and restore the files to their original state.
• Security baseline check: Server Guard can perform security baseline checks on servers to evaluate their security posture and compliance level. Server Guard can check more than 40 security items, such as system configuration, account management, network security, and log audit. Server Guard can also provide security hardening suggestions and one-click fixes for the detected issues.
• Security situation awareness: Server Guard can provide a comprehensive and visualized view of the security situation of the servers, such as the number of attacks, the attack sources, the attack types, the attack trends, and the security score. Server Guard can also provide security reports and recommendations for improving the security level of the servers. References: Security Center

 B, C, and E are the correct answers according to the ACA Cloud Computing by Alibaba Cloud Academy Reference Materials and documents. Comprehensive and Detailed Explanation: = B, C, and E are the correct answers because they are suitable services for developing a highly available web application using stateless web servers.

• B is correct because Server Load Balancer (SLB) is a service that distributes network traffic across groups of backend servers to improve the service capability and application availability. SLB can handle sudden spikes in traffic, minimize response time, and maintain 99.99% availability of the web application. SLB also supports health checks, session persistence, and cross-zone load balancing1
• C is correct because Elastic Compute Service (ECS) is a service that provides scalable and high-performance virtual machines for various computing needs. ECS can run stateless web servers that can be easily scaled up or down based on the demand. ECS can also use Auto Scaling to automate the scaling process and Elastic Self-Health to automatically recover from failures. ECS can also leverage the Alibaba Cloud network infrastructure, such as VPC, Express Connect, and Global Accelerator, to optimize the network connectivity and performance of the web servers2
• E is correct because Object Storage Service (OSS) is a service that provides massive, secure, and cost-effective storage for static files, such as images, videos, and documents. OSS can store the static content of the web application and reduce the load and cost of the ECS instances. OSS can also integrate with CDN to accelerate the delivery of the static content and improve the user experience and response time of the web application3

A and D are incorrect answers because they are not suitable services for developing a highly available web application using stateless web servers.

• A is incorrect because Relational Database Service (RDS) is a service that provides managed database systems, such as MySQL, SQL Server, PostgreSQL, and PPAS. RDS is not a stateless web server, but a stateful data storage and processing service. RDS can be used to store the dynamic data of the web application, but it is not suitable for hosting the web application itself4
• D is incorrect because MaxCompute is a service that provides a fast and fully managed big data platform for large-scale data warehousing. MaxCompute is not a stateless web server, but a data analysis and processing service. MaxCompute can be used to perform complex data analytics and machine learning tasks, but it is not suitable for hosting the web application itself.

References: 1: SLB Overview 2: ECS Overview 3: OSS Overview 4: RDS Overview : [MaxCompute Overview]

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

 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]

 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.

Alibaba Cloud Monitor service is a service that monitors the running status of Alibaba Cloud resources and custom metrics, and provides alert notifications and data visualization features. A user receives an alert saying that the IOPS utilization rate for an ECS instance exceeds 80%, which means that the disk performance of the instance is reaching its limit and may affect the application performance. To handle the situation, the user may obtain help from Alibaba Cloud through the following methods:

• Check ECS or CloudMonitor product documents: The user can check the official documentation of ECS or CloudMonitor to learn more about the concepts, features, operations, and best practices of these services. For example, the user can find the information about how to view the IOPS utilization rate of an ECS instance, how to optimize the disk performance of an ECS instance, and how to configure alert rules for CloudMonitor.
• Open a ticket to Alibaba Cloud help desk: The user can open a ticket to Alibaba Cloud help desk to get technical support from Alibaba Cloud engineers. The user can choose the ticket type, severity, and product, and describe the problem in detail. The user can also attach screenshots or logs to the ticket to help the engineers diagnose the problem. The user can track the status and response of the ticket in the console.
• Look for answers in Alibaba Cloud forum: The user can look for answers in Alibaba Cloud forum, which is a platform where Alibaba Cloud users can share their experiences, ask questions, and discuss topics related to Alibaba Cloud products and services. The user can search for relevant keywords or tags, browse the existing threads, or post a new question in the forum. The user can also interact with other users or Alibaba Cloud experts in the forum.

D. You cannot obtain any help from Alibaba Cloud is not a correct answer, as Alibaba Cloud provides various ways to help its users with their problems and questions. References: : [What is CloudMonitor? - CloudMonitor - Alibaba Cloud Documentation Center]. : [View the IOPS utilization of an ECS instance - CloudMonitor - Alibaba Cloud Documentation Center]. : [Optimize the disk performance of an ECS instance - Elastic Compute Service - Alibaba Cloud Documentation Center]. : [Configure alert rules - CloudMonitor - Alibaba Cloud Documentation Center].

 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