Alibaba Cloud ACA-Cloud1 - ACA Cloud Computing Associate

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

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

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

Auto Scaling is a management service that can automatically adjust elastic computing resources based on your business needs and policies. Auto Scaling supports the following features12:

Elastic Scale-Out: Automatically adds ECS instances to handle increased workloads.

Elastic Scale-In: Automatically removes ECS instances to reduce costs when workloads decrease.

Elastic Self-Health: Automatically replaces unhealthy ECS instances to ensure high availability and reliability.

Scheduled Scaling: Automatically adds or removes ECS instances based on predefined schedules.

Predictive Scaling: Automatically predicts future workloads and adjusts ECS instances accordingly.

Elastic Self-Diagnostic is not a feature supported by Alibaba Cloud Auto Scaling. It is a fictitious term that does not exist in the Alibaba Cloud documentation or course materials. References: 1: Auto Scaling: Automatically Adjusts Computing Resources - Alibaba Cloud 2: Auto Scaling:What is Auto Scaling? - Alibaba Cloud

 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

 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

Alibaba Cloud Auto Scaling service allows you to automatically adjust the number of ECS instances in a scaling group based on your business needs and scaling policies. You can set the minimum and maximum number of instances in a scaling group to limit the range of scaling actions1. When you create a scaling rule, you can specify the number of instances to be added or removed, or the expected number of instances after the scaling action2. You can also create a scheduled task to execute a scaling rule at a specified time or periodically3.

In this question, the customer sets the minimum number of instances to 6 and the maximum number of instances to 8 in the scaling group. This means that the scaling group will always have at least 6 instances and at most 8 instances. The customer also adds a scaling rule to remove 5 instances, and creates a scheduled task based on this rule. However, this scaling rule will not be executed if it violates the minimum and maximum limits of the scaling group. Therefore, when the scheduled task is activated once, the scaling group will only remove 2 instances, which is the difference between the current number of instances (8) and the minimum number of instances (6). The remaining number of instances in the scaling group will be 6, which is the correct answer. References: 1: Create a scaling group - Auto Scaling - Alibaba Cloud Documentation Center2: Create a scaling rule - Auto Scaling - Alibaba Cloud Documentation Center3: Create a scheduled task - Auto Scaling - Alibaba Cloud Documentation Center.

An ICP license is a permit issued by the Chinese Ministry of Industry and Information Technology (MIIT) that allows websites to operate in China. An ICP license is required for any website that is hosted on a mainland China server, or that wants to use a China-based CDN service to accelerate its access in China. Therefore, you would need to apply an ICP license in the following cases:

Accelerate your Overseas Website in China: If you have a website that is hosted outside of China, but you want to use Alibaba Cloud’s CDN service to improve its performance and user experience in China, you would need to apply an ICP license for your domain name. This is because Alibaba Cloud’s CDN nodes are located in mainland China, and any website that uses them must comply with the Chinese regulations.

Launch your website in China: If you want to host your website on an Alibaba Cloud ECS instance or OSS bucket that is located in mainland China, you would need to apply an ICP license for your domain name. This is because any website that is hosted on a mainland China server must have an ICP license to be accessible and legal in China.

Launch your online shop in China: If you want to run an e-commerce website that sells goods or services to customers in China, you would need to apply an ICP license for your domain name. This is because any website that engages in commercial activities in China must have an ICP license to operate legally and securely in China.

References: What is an ICP License? - Alibaba Cloud Academy, ICP License Application - Alibaba Cloud Documentation Center

Object Storage Service (OSS) is a cloud storage service that provides secure, cost-effective, and scalable storage for various data types, such as images, videos, and documents. OSS can store large amounts of data and support concurrent access from multiple users. OSS can also integrate with other Alibaba Cloud services, such as Media Transcoding Service (MTS), Server Load Balancer (SLB), and Elastic Compute Service (ECS). By using OSS, the portal can offload the storage and delivery of the image content from the ECS instance, which can improve the performance and availability of the application.

Content Delivery Network (CDN) is a distributed network that delivers content to users based on their geographic locations, the origin servers, and the content delivery policies. CDN can accelerate the delivery of static and dynamic content, such as images, videos, and web pages, by caching the content at edge nodes that are closer to the users. CDN can also reduce the network latency and bandwidth consumption, as well as enhance the security and reliability of the content delivery. By using CDN, the portal can speed up the loading of images and improve the user experience.

Therefore, the combination of OSS and CDN can help resolve the storage and performance issue of the portal at the same time. The other combinations are not as effective or suitable for the portal’s scenario. OSS + MTS combination can help with the storage and transcoding of media files, but not with the delivery of images. OSS + RDS combination can help with the storage and management of relational databases, but not with the loading of images. OSS + ECS combination can help with the storage and computing of data, but not with the acceleration of content delivery.

References:

Alibaba Cloud Object Storage Service

Alibaba Cloud Content Delivery Network

ACA Cloud Computing Certification Exam Preparation Course