ACA-Cloud1 Exam Dumps - ACA Cloud Computing Associate

 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

Session persistence feature in Server Load Balancer means that it can forward the access requests from a single user to the same ECS instance within a certain period to ensure session continuity. This feature is useful for applications that require users to maintain a stateful connection with the backend servers, such as online shopping or banking. Session persistence can be enabled by configuring a cookie timeout period or a source IP hash method in the Server Load Balancer console. References: ACA Cloud Computing Certification - Alibaba Cloud Academy, Server Load Balancer - Alibaba Cloud Academy, Session Persistence - Alibaba Cloud Documentation Center

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.

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

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 different load balancing algorithms, such as round robin, weighted round robin, and least connections. When using the weighted round robin algorithm, SLB assigns different weights to backend ECS instances based on their processing capabilities. The higher the weight of a backend ECS instance, the more requests it will receive from SLB. However, the weight of a backend ECS instance is not the only factor that determines the load distribution. The number and the weight of other backend ECS instances in the same server group also affect the load balancing result. Therefore, without knowing the weight settings of the remaining 4 ECS instances, we cannot tell what would happen to the load distribution among the 5 ECS instances. The other statements are incorrect because they assume a fixed or proportional load distribution based on the weight of ecs_inst1, which is not necessarily true.

References:

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

 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

 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

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, 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

 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.

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

 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

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

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

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

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.

 A is the correct answer because Auto Scaling supports adding existing ECS instances into the scaling group, whose status however must be running. Running means that the ECS instance is in a normal state and can provide services. Auto Scaling does not support adding ECS instances that are in other states, such as created, stopped, or preparing. Created means that the ECS instance has been created but has not been started yet. Stopped means that the ECS instance has been stopped and cannot provide services. Preparing means that the ECS instance is being initialized and cannot provide services12

B, C, and D are incorrect answers because they are not valid states for adding existing ECS instances into the scaling group.

References: 1: Add existing ECS instances to a scaling group 2: ECS instance lifecycle

 A is the correct answer because RDS provides whitelist access policies that allow you to set permitted IP addresses and IP network segments to effectively prevent hackers from attacking the server by port scanning. A whitelist is a security feature that specifies the IP addresses or CIDR blocks that are allowed to access your RDS instance. By default, the whitelist is empty, which means that no IP address can access your RDS instance. You can add IP addresses or CIDR blocks to the whitelist according to your business needs. You can also create multiple whitelist groups and assign different IP addresses or CIDR blocks to each group. This can help you manage the access permissions of different users or applications12

References: 1: Configure a whitelist 2: ApsaraDB RDS:Configure an IP address whitelist