Alibaba ACA Cloud Computing Associate ACA-Cloud1 Exam Questions

Answer : D

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.Reference:1: Auto Scaling: Automatically Adjusts Computing Resources - Alibaba Cloud2: Auto Scaling:What is Auto Scaling? - Alibaba Cloud

Answer : B

SQL injection is a common application layer attack that targets the database of a web application. SQL injection exploits a security vulnerability in the application's software, such as incorrect filtering of user input, that allows an attacker to send malicious SQL statements to the database.These statements can then be executed to steal, modify, or delete data, or even execute commands on the server1.SQL injection can also bypass authentication and authorization mechanisms, and sometimes even impersonate or damage the underlying system2.SQL injection is one of the most common and dangerous web attacks, and it can cause serious damage to the confidentiality, integrity, and availability of web applications3.Reference:1:SQL Injection - OWASP2:SQL Injection - Web Application Firewall - Alibaba Cloud Documentation Center3:Web Application Firewall:What is WAF? - Alibaba Cloud.

Answer : B

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.Reference: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.

Answer : D

Alibaba Cloud does not support intranet communication between products that are not in the same region, which means that ECS instances in different regions cannot communicate with each other on the intranet, and ECS instances and other products in different regions, such as ApsaraDB for RDS and OSS instances, cannot communicate with each other on the intranet. However, this does not mean that Server Load Balancer cannot be deployed for ECS instances in various regions. Server Load Balancer 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.Server Load Balancer supports cross-region deployment, which means that it can distribute traffic to ECS instances in different regions12.Reference:1: ACA Cloud Computing Exam Preparation Course - Alibaba Cloud32: Server Load Balancer - Alibaba Cloud Documentation Center4

Answer : A

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.Reference:Use Alibaba Cloud CDN to accelerate access to OSS

Answer : A

RDS for MySQL is aPlatform 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.Reference:MySQL Database Concepts and Operations - Alibaba Cloud Academy,Alibaba RDS Course | Cloud Academy,ACA Cloud Computing Certification - Alibaba Cloud Academy

Answer : A

Cloud disks are reliable because they use adistributed file management system with 3 redundant copiesto provide block-level data storage for ECS instances, ensuring99.9999999% data reliability. This means that the data stored on cloud disks is automatically replicated across three different physical servers in the same zone. If one server fails, the data can still be accessed from the other two servers. Cloud disks also support snapshot backup and recovery, which can help users restore data to a previous point in time in case of accidental deletion or corruption.Reference:Elastic Compute Service (ECS) - Alibaba Cloud Academy, Cloud Disk - Alibaba Cloud Documentation Center

An ECS disk can be used jointly or separately to meet the requirements of different application scenarios. ECS disks are categorized into ephemeral SSD disks and cloud disks. Compared with ephemeral SSD disks, cloud disks are more reliable as they use a triplicate distributed system to provide block-level data storage for ECS instances, ensuring 99.9999999% data reliability.