ACA-Cloud1 Exam Dumps - ACA Cloud Computing Associate

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