Alibaba ACA Cloud Computing Associate ACA-Cloud1 Exam Practice Test

Answer : A

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.

Answer : A, B, C, D

A, B, C, and D are the correct answers according to the ACA Cloud Computing by Alibaba Cloud Academy Reference Materials and documents.Comprehensive and Detailed = A, B, C, and D are the correct answers because ECS is a highly flexible service that can be used independently as a simple web server, or used with other Alibaba Cloud products, such as OSS and CDN, to provide advanced solutions. ECS can be used in applications such as:

Official corporate websites: ECS can host official corporate websites that require high performance, stability, reliability, and scalability. ECS can also support various web frameworks and languages, such as PHP, Java, Node.js, Python, and Ruby.ECS can also be integrated with other Alibaba Cloud products, such as SLB, CDN, and WAF, to improve the security, availability, and performance of the websites1

Large-traffic apps: ECS can handle large-traffic apps that require high concurrency, low latency, and high throughput. ECS can also scale up or down based on the real-time traffic demands, and use Auto Scaling to automate the scaling process.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 apps2

Databases: ECS can run various database systems, such as MySQL, PostgreSQL, MongoDB, and Redis, to provide data storage and processing capabilities for different applications. ECS can also use cloud disks or local disks as the storage media for the databases, and choose different disk types, such as SSD, ESSD, and Ultra Disk, based on the performance and cost requirements.ECS can also use RDS or PolarDB to replace the self-managed databases, and enjoy the benefits of managed database services, such as backup, recovery, monitoring, and maintenance3

Simple web applications: ECS can run simple web applications that do not require complex architectures or high availability. ECS can provide fast memory and the latest CPUs to power the web applications and achieve faster results with low latency. ECS can also use OSS to store static files, such as images, videos, and documents, and reduce the storage cost and load of the ECS instances.

E is an incorrect answer because ECS is not a storage service that provides unlimited online storage. ECS is a compute service that provides virtual machines with limited storage capacity. ECS can use OSS or NAS to expand the storage capacity, but these are separate storage services that have their own pricing and billing methods.

Answer : A

Server Load Balancer (SLB) can help protect from distributed denial-of-service (DDoS) attacks by distributing network traffic across groups of backend servers to improve the service capability and application availability. SLB also supports built-in Anti-DDoS services to ensure business security.Anti-DDoS services can mitigate DDoS attacks at the Tbit/s level and provide multiple defense methods, such as blackhole filtering, traffic scrubbing, and access control1.In addition, you can integrate Application Load Balancer (ALB) with Web Application Firewall (WAF) in the console to ensure security at the application layer and prevent attacks such as SQL injection2.Reference:1:Server Load Balancer(SLB) - Alibaba Cloud2:Associate an EIP protected by Anti-DDoS Pro/Premium with an ALB instance - Server Load Balancer - Alibaba Cloud Documentation Center.

Answer : B

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.

Answer : A, B, C

When using Alibaba Cloud OSS, you can set access control in three different levels, which are bucket level, object level, and RAM account level. Bucket level access control is the highest level of access control, which determines whether a user can access the bucket and its objects. Bucket level access control can be set to public read/write, public read, or private. Object level access control is the second level of access control, which determines whether a user can access a specific object in the bucket. Object level access control can be set to inherit from the bucket, public read/write, public read, or private. RAM account level access control is the lowest level of access control, which determines whether a user can perform certain operations on the bucket or the object. RAM account level access control can be set by using RAM policies, which specify the actions, resources, and conditions for the access.Reference:Object Storage Service (OSS) - Alibaba Cloud Academy,Access Control - Alibaba Cloud Documentation Center

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.

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Explanation

Answer : A

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.Reference:1: ACA Cloud Computing Exam Preparation Course - Alibaba Cloud32: What Is Alibaba Cloud Academy Certification?4