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

Elastic Computing Service (ECS) is a cloud computing service that provides scalable, on-demand computing resources for cloud applications. ECS offers elastic computing, elastic storage, and elastic network features to meet different business needs. However, ECS does not provide elastic administration, which means that the management and configuration of ECS resources are not automatically adjusted according to the workload or demand. Users need to manually create, modify, or delete ECS instances, disks, snapshots, security groups, and other resources. Users can also use other Alibaba Cloud services, such as Auto Scaling, Server Load Balancer, and Cloud Monitor, to enhance the elasticity and availability of ECS.

References:

[Alibaba Cloud Elastic Compute Service]

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Alibaba Cloud ACA-Cloud1 ACA Cloud Computing Certification Exam

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

 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

A large shopping mall deploys a new video surveillance system. The five-floor building in which the mall is located installed 35 HD cameras to monitor the major exits. The surveillance system is deployed on an ECS instance, which has four 2 TB data disks to store video data.

However, video data grows rapidly and the engineers find that the ECS will run out of storage space within 2 weeks.

In this case, OSS is thought to be the best solution for addressing the storage challenge while ensuring quick access to historical video data when needed. OSS is a cloud-based object storage service that provides massive, secure, low-cost, and highly reliable storage for unstructured data such as images, videos, and documents. OSS can store any amount of data and scale up or down on demand. OSS also supports direct video stream storage capabilities, removing the need for a video segmentation cluster. OSS can be accessed through RESTful APIs, SDKs, or web consoles, and can be integrated with other Alibaba Cloud services such as CDN, ECS, and SLB. OSS provides various storage classes for different data storage scenarios, from hot data storage to cold data storage. For video surveillance data, the Infrequent Access (IA) or Archive storage classes can be used to reduce the storage cost while maintaining high data durability and availability123. References: 1: Alibaba Cloud Multimedia Solutions | Video Monitoring & Surveillance1 2: Overview - Object Storage Service - Alibaba Cloud2 3: OSS Concepts - Alibaba Object Storage Service Course - Cloud Academy

 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]

OSS object types are the storage classes that define the performance and cost of storing objects in OSS. OSS supports four object types: Standard, Infrequent Access (IA), Archive, and Cold Archive1. Each object type has different characteristics and scenarios, such as availability, durability, minimum storage duration, and storage overhead2.

Object lifecycle management is a feature that allows you to manage objects efficiently and minimize costs throughout the lifecycle of the objects in your bucket. Lifecycle settings create a set of rules that help define the actions that an OSS bucket must perform on a group of objects. For example, you can configure lifecycle rules to automatically delete expired objects, or convert the storage class of objects to a lower-cost object type3.

You can configure lifecycle rules based on the object type of the objects in your bucket. You can specify the object type as a parameter for the lifecycle rule, and OSS will apply the rule to the objects that match the object type. For example, you can create a lifecycle rule to convert the object type of objects from Standard to IA after 30 days, and then to Archive after 180 days4.

Therefore, the correct answer is A. Infrequent access and C. Archive, as these are two of the object types that can be configured as parameters for object lifecycle management. B. Snapshot and D. Chunk are not valid object types in OSS. References: 1: Overview of object types - Object Storage Service - Alibaba Cloud Documentation Center2: Object Storage Service (OSS) - Alibaba Cloud3: Manage Your OSS Storage Costs Using Lifecycle Policies - Alibaba Cloud4: Lifecycle rules based on the last modified time - Object Storage Service - Alibaba Cloud Documentation Center.

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

 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

 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

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