ACA-Cloud1 Sample Questions Answers

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

 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

 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

Session state data is the information that is associated with a specific user session, such as user preferences, shopping cart items, authentication tokens, etc. Session state data needs to be stored in a persistent and scalable way, so that it can be accessed by multiple web servers and survive server failures. Therefore, the suitable services for storing session state data are those that provide reliable, distributed, and high-performance data storage, such as RDS and Table Store.

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. RDS provides high availability, backup and recovery, security, and monitoring features for your databases. RDS can store session state data in relational tables, and you can use SQL queries to access and manipulate the data.

Table Store is a fully managed NoSQL database service that provides consistent, scalable, and high-performance data storage for structured and semi-structured data2. Table Store organizes data in tables, rows, and columns, and supports primary key and attribute columns. Table Store can store session state data in flexible schemas, and you can use primary key queries or secondary index queries to access and manipulate the data.

References: 1: Alibaba Cloud Academy, “RDS Concepts”, https://edu.alibabacloud.com/elearning/lesson/ACA-Cloud-Computing-Certification/lesson-5-rds-concepts  2: Alibaba Cloud Academy, “Table Store”, https://edu.alibabacloud.com/elearning/lesson/ACA-Cloud-Computing-Certification/lesson-7-table-store

 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 …

 You can create a custom image for ECS using data disk snapshots or system disk snapshots. A snapshot is a backup of the data on a disk at a specific point in time. You can use snapshots to create custom images, which are copies of the operating system and applications on a disk. You can use custom images to create ECS instances that have the same operating system, applications, and data as the original disk12.

You cannot create a custom image for ECS using CPU snapshots or memory snapshots. These are not valid terms in Alibaba Cloud. CPU and memory are not persistent storage devices, and they do not store the operating system and applications that are required for creating a custom image34. References: 1: Create a custom image from a snapshot - Alibaba Cloud1 2: What is a custom image? - Alibaba Cloud2 3: What is a CPU? - Alibaba Cloud3 4: What is memory? - Alibaba Cloud4

You can upgrade or downgrade an ECS instance’s configuration to meet your business needs. Upgrading an instance’s configuration means increasing the vCPUs, memory, bandwidth, or disk capacity of the instance. Downgrading an instance’s configuration means decreasing the vCPUs, memory, bandwidth, or disk capacity of the instance. You can change the configuration of an ECS instance by using one of the following methods1:

• Change the instance type: You can change the instance type of an ECS instance to adjust the vCPUs and memory of the instance. You can change the instance type of an ECS instance in the following scenarios2:
• Change the bandwidth configuration: You can change the bandwidth configuration of an ECS instance to adjust the network performance of the instance. You can change the bandwidth configuration of an ECS instance in the following scenarios3:
• Change the system disk or data disk: You can change the system disk or data disk of an ECS instance to adjust the disk capacity or performance of the instance. You can change the system disk or data disk of an ECS instance in the following scenarios4:

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 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

Your website has oscillating traffic peaks that are difficult to predict in advance. In this scenario, it is recommended to use SLB and Auto Scaling together with ECS. 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 applications. 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 requests. By using SLB and Auto Scaling together with ECS, you can achieve high scalability and elasticity for your website, and cope with the changing traffic patterns12. References: 1: ACA Cloud Computing Exam Preparation Course - Alibaba Cloud3 2: Auto Scaling: Automatically Adjusts Computing Resources - Alibaba Cloud4

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

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 the memory size of an ECS instance is determined by the instance type, and it cannot be changed independently. If you want to change the memory size of an ECS instance, you must change the instance type to another one that has a different memory size12

B, C, and D are incorrect answers because the system disk size, data disk size, and number of data disks of an ECS instance can be changed without changing the instance type. You can use the ECS console or API to resize the system disk or data disks of an ECS instance, or add or remove data disks from an ECS instance3456

References: 1: Overview of instance families 2: Change the instance type 3: Resize disks 4: Resize a disk 5: Attach or detach data disks 6: Attach or detach a data disk

 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 and C are the correct answers because they can improve the performance of the platform by reducing the load on the ECS instances and the database server.

• A is correct because using CDN can accelerate the delivery of static content such as CSS and JavaScript files, which can reduce the bandwidth consumption and latency of the ECS instances. CDN can also cache the content in edge nodes closer to the end users, which can improve the user experience and response time of the platform1
• C is correct because using RDS can replace the existing self-built database, which can provide better database performance, reliability, security, and scalability. RDS can also handle the backup, recovery, monitoring, and maintenance of the database, which can reduce the management overhead and cost of the platform. Moreover, creating RDS read-only instances can handle read-only requests, which can reduce the workload on the master RDS instance and improve the database availability and performance23

References: 1: CDN Overview 2: RDS Overview 3: RDS Read-only Instances

ECS can be used along with OSS to store static images, videos, and reducing storage fees. OSS is a fully managed object storage service that provides industry-leading scalability, durability, and performance. OSS can store any amount of data from anywhere, such as static images, videos, backup files, and so on. ECS is a cloud computing service that provides elastic and secure virtual cloud servers. ECS can access OSS resources by using an internal endpoint of OSS, which reduces the network latency and the traffic costs. By using ECS and OSS together, you can benefit from the following advantages1:

• Improved user experience: You can use OSS to store and deliver static content, such as images and videos, to your users. OSS integrates with CDN products to provide reliable, scalable, flexible, and cost-effective content distribution solutions. You can use ECS to run dynamic applications, such as web servers and databases, that require high performance and availability. ECS provides fast memory and the latest CPUs to help you power your cloud applications and achieve faster results with low latency.
• Reduced storage fees: You can use OSS to store large amounts of data at a low cost. OSS offers four tiers of storage: Standard, Infrequent Access, Archive, and Cold Archive. Each tier is cost-optimized for specific storage patterns. You can use lifecycle policies to automatically transition your data to the appropriate storage tier based on your business needs. You can also use Storage Capacity Unit to plan your storage budget and usage in one place. You can use ECS to scale your computing resources up or down based on real-time demands. ECS supports pay-as-you-go and different capacity reservation plans. You can also use spot instances to reduce your computing costs by up to 90%.
• Enhanced security: You can use OSS to protect your data from unauthorized access, deletion, or modification. OSS supports encryption at rest and in transit, anti-leech protection, bucket policies, RAM roles, and more. You can also use your own key (BYOK) encryption to ensure your data is encrypted when it is stored in the cloud platform. You can use ECS to secure your cloud servers from network attacks, such as DDoS and brute force attacks. ECS supports security groups, firewalls, VPCs, SSL certificates, and more. You can also use Resource Access Management (RAM) to control the access permissions of your ECS instances and OSS buckets. References: Use Alibaba Cloud CDN to accelerate access to OSS

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, 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.