Alibaba Cloud ACA-Cloud1 ACA Cloud Computing Associate Exam Practice Test

 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

Load and Performance Testing Service (LPTS) is a service that helps users to test the performance and stability of their websites, applications, or servers under different load conditions. LPTS can simulate a large number of concurrent users and requests, and generate detailed reports on the response time, throughput, error rate, and other metrics of the target system. LPTS can help users to identify and resolve performance bottlenecks, optimize resource utilization, and ensure the reliability and availability of their online services. References: Load and Performance Testing Service - Alibaba Cloud Academy, Load and Performance Testing Service - Alibaba Cloud Documentation Center

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

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

 Prepaid is a charging mode that allows you to pay in advance for a certain amount of resources for a specified period of time. It is also known as subscription or reserved instance. Prepaid is more suitable for scenarios with relatively fixed traffic, such as an online ticket booking service, because it offers lower prices and more stable performance than pay-as-you-go. Pay-as-you-go is a charging mode that allows you to pay only for the resources you actually use on an hourly basis. It is more suitable for scenarios with unpredictable or fluctuating traffic, such as a news website or a social media platform. Paypal-pay and bitcoin-pay are not valid charging modes for Alibaba Cloud Computing products.

References: 1: Alibaba Cloud Academy, “Charging Modes”, https://edu.alibabacloud.com/elearning/lesson/ACA-Cloud-Computing-Certification/lesson-1-charging-modes

 Elastic Compute Service (ECS) is an IaaS offering on Alibaba Cloud that provides high-performance, stable, reliable, and scalable compute capacity in the cloud. ECS eliminates your need to invest in hardware up front. You can create as many or as few instances as you need in response to changes in requirements or popularity of your workloads. With an ever-growing selection of instance types, ECS provides broader and deeper choices to match a wide spectrum of computing needs. References: What is ECS? - Alibaba Cloud

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

 A, B, C, and D are the correct answers according to the ACA Cloud Computing by Alibaba Cloud Academy Reference Materials and documents. Comprehensive and Detailed Explanation: = A, B, C, and D are the correct answers because ECS is a highly flexible service that can be used independently as a simple web server, or used with other Alibaba Cloud products, such as OSS and CDN, to provide advanced solutions. ECS can be used in applications such as:

• Official corporate websites: ECS can host official corporate websites that require high performance, stability, reliability, and scalability. ECS can also support various web frameworks and languages, such as PHP, Java, Node.js, Python, and Ruby. ECS can also be integrated with other Alibaba Cloud products, such as SLB, CDN, and WAF, to improve the security, availability, and performance of the websites1
• Large-traffic apps: ECS can handle large-traffic apps that require high concurrency, low latency, and high throughput. ECS can also scale up or down based on the real-time traffic demands, and use Auto Scaling to automate the scaling process. 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 apps2
• Databases: ECS can run various database systems, such as MySQL, PostgreSQL, MongoDB, and Redis, to provide data storage and processing capabilities for different applications. ECS can also use cloud disks or local disks as the storage media for the databases, and choose different disk types, such as SSD, ESSD, and Ultra Disk, based on the performance and cost requirements. ECS can also use RDS or PolarDB to replace the self-managed databases, and enjoy the benefits of managed database services, such as backup, recovery, monitoring, and maintenance3
• Simple web applications: ECS can run simple web applications that do not require complex architectures or high availability. ECS can provide fast memory and the latest CPUs to power the web applications and achieve faster results with low latency. ECS can also use OSS to store static files, such as images, videos, and documents, and reduce the storage cost and load of the ECS instances.

E is an incorrect answer because ECS is not a storage service that provides unlimited online storage. ECS is a compute service that provides virtual machines with limited storage capacity. ECS can use OSS or NAS to expand the storage capacity, but these are separate storage services that have their own pricing and billing methods.

References: 1: Build a Corporate Website 2: Build a Large-Traffic App 3: Build a Database System : [Build a Simple Web Application] : [ECS Overview]

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

Alibaba Cloud Server Load Balancer (SLB) is a service that distributes network traffic across multiple ECS instances to improve the service capabilities of applications. SLB supports the following protocols for the listener configuration:

• HTTP: Hypertext Transfer Protocol, a stateless application-layer protocol that is used to transfer web pages and other resources over the internet.
• HTTPS: Hypertext Transfer Protocol Secure, an extension of HTTP that uses SSL/TLS encryption to provide secure communication between the client and the server.
• TCP: Transmission Control Protocol, a reliable, connection-oriented transport-layer protocol that provides reliable data delivery and error recovery.
• UDP: User Datagram Protocol, a connectionless transport-layer protocol that provides fast and efficient data transmission without guaranteeing reliability or order.

SLB does not support the following protocols:

• MPLS: Multiprotocol Label Switching, a data-carrying technique that uses labels to forward packets across a network.
• MQTT: Message Queuing Telemetry Transport, a lightweight publish/subscribe messaging protocol that is designed for constrained devices and low-bandwidth networks.

References:

• Alibaba Cloud Server Load Balancer
• ACA Cloud Computing Certification Exam Preparation Course
• Alibaba Cloud Computing Exam Question 2022

Comprehensive protocol support - ICMP, TCP, UDP, HTTP, HTTPS,

Alibaba Cloud Architecture Design Training is a service that provides professional guidance and best practices for designing cloud architectures that meet the business requirements and goals of the company. Alibaba Cloud Architecture Design Training can help the company to understand the cloud migration process, select the appropriate Alibaba Cloud products and services, design a secure, reliable, scalable, and cost-effective cloud architecture, and implement the migration plan with minimal risks and disruptions. Alibaba Cloud Architecture Design Training can also help the company to optimize the performance and efficiency of the cloud system after the migration.

References:

• Alibaba Cloud Architecture Design Training
• Cloud Migration - Alibaba Cloud Solutions
• ACA-Cloud1 Alibaba Exam Questions and Answers - CertLibrary

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].

 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 …

 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

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

SLB and Auto Scaling are two Alibaba Cloud services that can work together to provide high availability, scalability, and performance for your applications. SLB is a load balancing service that distributes incoming traffic across multiple ECS instances. Auto Scaling is a service that automatically adjusts the number of ECS instances based on your business needs. When you use SLB and Auto Scaling together, you need to follow some best practices and precautions to ensure the optimal performance and reliability of your system. One of the precautions is that SLB instances must have Health Check enabled, or they cannot be used together with Auto Scaling1. Health Check is a feature of SLB that monitors the health status of the backend ECS instances. If an ECS instance becomes unhealthy or fails, SLB automatically stops sending traffic to that instance and redirects the traffic to other healthy instances. This ensures that your application can continue to serve user requests without interruption. Health Check is also essential for Auto Scaling, because Auto Scaling relies on the health status reported by SLB to decide whether to add or remove ECS instances. If an ECS instance is unhealthy, Auto Scaling will automatically replace it with a new one. If the traffic increases and the average health status of the ECS instances decreases, Auto Scaling will automatically add more instances. If the traffic decreases and the average health status of the ECS instances increases, Auto Scaling will automatically remove some instances. Therefore, Health Check is a prerequisite for using SLB and Auto Scaling together. If you disable Health Check, SLB and Auto Scaling will not be able to communicate with each other and coordinate their actions. This may result in performance degradation, service interruption, or resource waste. The other options are incorrect, because they are not necessary or relevant for using SLB and Auto Scaling together. The backend ECS instances under the same SLB instance can have different operating systems, configurations, and scaling groups, as long as they can provide the same service and respond to the same requests. SLB and Auto Scaling do not impose any restrictions on these aspects of the ECS instances. References: Associate SLB instances with or disassociate SLB instances from a scaling group

Alibaba Cloud Server Load Balancer (SLB) is a service that distributes network traffic across multiple ECS instances to improve the service capabilities of applications. SLB supports the following protocols for the listener configuration:

• HTTP: Hypertext Transfer Protocol, a stateless application-layer protocol that is used to transfer web pages and other resources over the internet.
• HTTPS: Hypertext Transfer Protocol Secure, an extension of HTTP that uses SSL/TLS encryption to provide secure communication between the client and the server.
• TCP: Transmission Control Protocol, a reliable, connection-oriented transport-layer protocol that provides reliable data delivery and error recovery.
• UDP: User Datagram Protocol, a connectionless transport-layer protocol that provides fast and efficient data transmission without guaranteeing reliability or order.

SLB does not support the following protocols:

• MPLS: Multiprotocol Label Switching, a data-carrying technique that uses labels to forward packets across a network.
• MQTT: Message Queuing Telemetry Transport, a lightweight publish/subscribe messaging protocol that is designed for constrained devices and low-bandwidth networks.

References:

• Alibaba Cloud Server Load Balancer
• ACA Cloud Computing Certification Exam Preparation Course
• Alibaba Cloud Computing Exam Question 2022

 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

Alibaba Cloud OSS service provides different methods for file uploading, such as simple upload, multipart upload, append upload, and resumable upload1. However, not all of these methods support resuming from break point, which is a feature that allows you to resume an interrupted upload from where it left off. The only method that supports resuming from break point is resumable upload, which is based on multipart upload and uses a checkpoint file to record the upload progress2. The other methods do not support resuming from break point, and will either overwrite or append to the existing object if the upload is interrupted and retried.

References: 1: Alibaba Cloud Academy, “OSS Upload Methods”, https://edu.alibabacloud.com/elearning/lesson/ACA-Cloud-Computing-Certification/lesson-2-oss-upload-methods  2: Alibaba Cloud, “Resumable upload”, https://www.alibabacloud.com/help/doc-detail/31991.htm

Auto Scaling is a service that automatically adjusts computing resources based on your volume of user requests. When the demand for computing resources increases, Auto Scaling automatically adds ECS instances to serve additional user requests, or alternatively removes instances in the case of decreased user requests1. Auto Scaling can help you manage traffic peaks efficiently and maintain a consistent user experience by scaling up or down your ECS instances according to your predefined policies and business needs2. References: 1: Auto Scaling: Automatically Adjusts Computing Resources - Alibaba Cloud2: Overview - Auto Scaling - Alibaba Cloud Documentation Center.

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.