ACP-Cloud1 Sample Questions Answers

The difference between public and private Server Load Balancers (SLBs) is that private SLBs connect to their backend ECS instances using the private network (Intranet) while public SLBs connect to their backend ECS instances using the public network (Internet). This is true according to the Alibaba Cloud documentation on SLB1. Public SLBs are used to distribute traffic from the Internet to ECS instances, while private SLBs are used to distribute traffic within a VPC or a classic network2. References: 1: Server Load Balancer - Alibaba Cloud Documentation Center 2: Create a Server Load Balancer instance - Server Load Balancer - Alibaba Cloud Documentation Center

According to the Alibaba Cloud Elastic Compute Service documentation, if the current public bandwidth does not meet your business requirements, you can upgrade or downgrade the public bandwidth configurations without the need to reboot the ECS instance. This can improve the network performance and response speed of the ECS instance. Upgrading the CPU, memory, or disk of the ECS instance may not solve the issue of bandwidth utilization, and may require rebooting the ECS instance. References: Public bandwidth - Elastic Compute Service

 A DDoS attack is a type of cyberattack that aims to exhaust the resources of a target server or network, such as bandwidth, CPU, memory, or disk space, by sending a large amount of malicious traffic or requests. This can cause the server or network to slow down, crash, or become unavailable to legitimate users. A DDoS attack is not intended to steal confidential information, crack passwords, or target databases, although these may be secondary objectives or consequences of some attacks. A DDoS attack is one of the most common and powerful threats to website security, as it can be launched from multiple sources, use various attack methods, and evade traditional defense mechanisms. According to the DDoS Attack Statistics and Trend Report by Alibaba Cloud, the proportion of volumetric attacks at 50Gbps and above has doubled, and the resources exhaustion attack reached a peak value of 3 million QPS in 2020-2021. References: DDoS Attacks: Sources, Strategies and Practices - Alibaba Cloud, DDoS Attack Statistics and Trend Report by Alibaba Cloud, Use Alibaba Cloud Anti-DDoS Service to Defend DoS Attack, Anti-DDoS Basic - Alibaba Cloud

 When the scheduled task is activated once, 4 ECS instances will be added in the scaling group. This is because the scaling rule “Add 6 ECS instances” will increase the number of instances in the scaling group to 9, which exceeds the maximum number of instances (7) that is set for the scaling group. Therefore, Auto Scaling will only add 4 ECS instances to reach the maximum number of instances. The remaining 2 ECS instances will not be added to avoid exceeding the quota. 

 You do not need to activate and purchase Alibaba Cloud CloudMonitor service to monitor the status of the ECS instance via Alibaba Cloud console. CloudMonitor is a service that monitors Alibaba Cloud resources and Internet applications. CloudMonitor provides a one-stop, out-of-the-box, and enterprise-class monitoring solution1. CloudMonitor collects monitor metrics of Alibaba Cloud resources and custom metrics and enables you to view and understand the usage of the cloud resources, and the health of your business2. CloudMonitor allows you to monitor the metrics of Alibaba Cloud services, detect the availability of websites hosted on ECS instances or carrier servers, and configure alert rules for specified metrics3. However, CloudMonitor is not a prerequisite for monitoring the status of the ECS instance via Alibaba Cloud console. You can monitor the status of the ECS instance via Alibaba Cloud console without activating and purchasing CloudMonitor service. You can view the basic information, configuration, security group, and tags of the ECS instance in the console. You can also view the CPU, memory, disk, and network usage of the ECS instance in the console. You can also use the Cloud Assistant feature to run commands on the ECS instance remotely4. 

 You can change the private IP address of an ECS instance after it is created, but you need to stop the instance first. The private IP address must be within the CIDR block of the VPC and the VSwitch that the instance belongs to. You can modify the private IP address of an instance by using the console or the API. References: 3, ACP Cloud Computing Certification - Alibaba Cloud Academy

After stopping an Alibaba Cloud Elastic Compute Service (ECS) instance, you will still be charged for some resources related to that ECS instance, such as disks, snapshots, and public IP addresses, until you release them. The charging policy depends on the billing method and network type of the ECS instance. For pay-as-you-go instances, you can choose whether to enable the No fees for stopped instances feature, which allows you to stop paying for vCPUs and memory when the instance is stopped. However, this feature is only available for VPC-connected instances in some regions1. For subscription instances, you will be charged for the entire subscription period regardless of whether the instance is running or stopped2. References:

• 1: Billing FAQ - Elastic Compute Service - Alibaba Cloud Documentation Center1
• 2: Billing overview - Elastic Compute Service - Alibaba Cloud Documentation Center2

When creating an ECS instance in your Alibaba Cloud VPC, you must specify a VSwitch for that instance at the same time. Otherwise, you will not be able to create this ECS instance. This is true according to the Alibaba Cloud documentation on ECS1. A VSwitch is a basic network device of a VPC and is used to connect different cloud product instances deployed in a VPC2. A VSwitch defines a network segment within a VPC and allows you to specify the IP address range, network mask, and gateway for the network segment2. When you create an ECS instance, you must select a VSwitch that belongs to the same zone as the ECS instance3. If you do not specify a VSwitch, the ECS instance will not be able to communicate with other cloud product instances in the VPC or access the Internet. References: 1: Create an instance by using the provided wizard - Elastic Compute Service - Alibaba Cloud Documentation Center 2: What is a VSwitch? - Virtual Private Cloud - Alibaba Cloud Documentation Center 3: Create an instance by using the advanced wizard - Elastic Compute Service - Alibaba Cloud Documentation Center : [VPC FAQ - Virtual Private Cloud - Alibaba Cloud Documentation Center]

OSS does not use a hierarchical structure for objects, but instead uses a flat structure. All elements are stored as objects in buckets. To use OSS in the same manner in which local file systems are used, you can configure Cloud Storage Gateway (CSG).

https://www.alibabacloud.c om/help/doc-detail/31817.htm

 The statement C is correct, because in an OSS bucket, all elements are stored as objects. An object is the basic unit of OSS storage. Each object consists of a unique key, data, and metadata. The key is the name of the object, which is used to identify the object in a bucket. The data is the content of the object, which can be any type of file, such as text, image, video, or audio. The metadata is the information about the object, such as its size, type, creation time, and custom attributes. References: = Object Storage Service:Overview - Alibaba Cloud

 When using Alibaba Cloud SLB, users can enable the health check function to monitor the availability of the backend ECS instances. If a backend ECS instance A is running abnormally, SLB will stop forwarding requests to it and distribute them to other healthy ECS instances. This way, SLB can ensure the high availability and reliability of the service. When the backend ECS instance A is back to normal, SLB will resume forwarding requests to it. SLB performs health checks on the backend ECS instances at regular intervals and updates their status accordingly. Users can configure the health check parameters such as the protocol, port, interval, timeout, and threshold on the SLB console or by using the API. References: 1 - Health checks - Server Load Balancer - Alibaba Cloud Document Center - Health check overview

 Object Storage Service (OSS) supports sub accounts, which are the accounts that belong to a parent account and share the resources of the parent account. You can allocate access permissions to different buckets for each sub account by using bucket policies or RAM policies. Bucket policies are the access control policies that are attached to buckets and specify the permissions that other users have on the resources in the buckets. RAM policies are the access control policies that are attached to RAM users or RAM user groups and specify the permissions that the RAM users or RAM user groups have on the OSS resources. References:

• Object Storage Service:Overview - Alibaba Cloud
• Object Storage Service:FAQ - Alibaba Cloud
• Authentication - Object Storage Service - Alibaba Cloud

The X-Forwarded-For field in HTTP header is used to identify the originating IP address of a client connecting to a web server through an HTTP proxy or a load balancer. When the “Obtain the Visitor’s Real IP Address” function is enabled in Alibaba Cloud SLB, the SLB instance adds the X-Forwarded-For field to the HTTP header of each request and forwards the request to the backend server. The backend server can then obtain the real IP address of the visitor from the X-Forwarded-For field1. The format of the X-Forwarded-For field is as follows:

X-Forwarded-For: client, proxy1, proxy2

where the value is a comma+space separated list of IP addresses, the left-most being the original client, and each successive proxy that passed the request adding the IP address where it received the request from. In this example, the request passed through proxy1, proxy2, and then the SLB instance (proxy3).2

References: Obtain client IP addresses - Server Load Balancer - Alibaba Cloud, X-Forwarded-For - MDN Web Docs

RDS for MySQL supports both full backups and incremental backups. A full backup is a complete backup of all data in a database. An incremental backup is a backup of only the data that has changed since the last backup. Incremental backups can reduce the backup time and storage space. You can configure the backup cycle and retention period for both types of backups in the RDS console or by using the API.

When using Alibaba Cloud SLB, you can set different weights for backend ECS instances. The higher the weight of a backend ECS instance, the more load will be assigned to it. However, the load distribution is not based on the absolute value of the weight, but on the proportion of the weight in the total weight of all healthy backend ECS instances. For example, if there are two healthy backend ECS instances with weights of 100 and 200 respectively, the first instance will receive 33.3% of the load, and the second instance will receive 66.7% of the load. Therefore, to determine the load distribution of the 5 ECS instances in the question, we need to know the weight settings of the remaining 4 ECS instances. Without this information, we cannot tell what would happen. The other options are incorrect because they are based on wrong assumptions or misunderstandings of the SLB weight setting mechanism. 

https://cloudacademy.com/course/alibaba-security-monitoring-1275/introduction-to-cloud-monitor/#:~:text=Cloud%20Monitor%20is%20a%20service,safeguard%20your%20products%20and%20business .

• Option A is correct because site monitoring is one of the functions provided by CloudMonitor. Site monitoring monitors the availability, connectivity, and domain name resolution of sites. It monitors the connectivity and response time of domain names, IP addresses, and ports, and sends alert notifications based on monitoring results1
• Option B is correct because customized monitoring is one of the functions provided by CloudMonitor. Customized monitoring allows you to monitor the metrics of your own applications or services. You can use the CloudMonitor API or SDK to report custom metrics to CloudMonitor and view them on the CloudMonitor console. You can also configure alert rules for your custom metrics2
• Option E is correct because cloud service monitoring is one of the functions provided by CloudMonitor. Cloud service monitoring monitors the metrics of Alibaba Cloud services, such as Elastic Compute Service (ECS), Object Storage Service (OSS), ApsaraDB for RDS, and Server Load Balancer (SLB). CloudMonitor collects the metrics of these services and displays them on the CloudMonitor console. You can also configure alert rules for these metrics2
• Option C is incorrect because custom firewall is not a function provided by CloudMonitor. Custom firewall is a feature of Alibaba Cloud Security Center, which is a different service from CloudMonitor. Security Center provides security protection for your cloud resources and applications. Custom firewall allows you to customize firewall rules for your ECS instances and control the inbound and outbound traffic3
• Option D is incorrect because operation auditing is not a function provided by CloudMonitor. Operation auditing is a feature of Alibaba Cloud ActionTrail, which is a different service from CloudMonitor. ActionTrail records the operations performed on your Alibaba Cloud resources and delivers the audit logs to OSS or Log Service for storage and analysis. Operation auditing helps you track the changes of your resources and comply with security standards4

References:

• 2: What is CloudMonitor? - CloudMonitor - Alibaba Cloud Documentation Center
• 1: Introduction to Cloud Monitor - Alibaba Security & Monitoring Course
• 3: [Security Center - Alibaba Cloud]
• 4: [ActionTrail - Alibaba Cloud]

 To execute a task at a specific time such as removing 1 ECS instance every night at 00:00, you need to perform two operations: create a scaling rule and create a scheduled task. A scaling rule is a set of instructions that defines how Auto Scaling scales computing resources in response to changes in business load. A scheduled task is a type of scaling task that can execute a specified scaling rule at a specified time. By creating a scaling rule that removes 1 ECS instance from the scaling group, and creating a scheduled task that executes this scaling rule every night at 00:00, you can achieve the desired result. You do not need to create a new scaling group, because you already have one scaling group created. You also do not need to create an event-triggered task, because this type of scaling task is triggered by events such as Cloud Monitor alarms or API calls, not by a specific time. References: 1, 2, and 3.

According to the Alibaba Cloud ECS documentation1, the Pay-As-You-Go billing method is flexible and suitable for short-term or uncertain workloads. However, it is also the most expensive option compared to other billing methods. To reduce the cost of Pay-As-You-Go instances, you can purchase a Savings Plan, which is a discount plan that offers lower prices for a fixed amount of hourly usage. A Savings Plan can be applied to any Pay-As-You-Go instance in the same region, regardless of the instance type, operating system, or zone. Therefore, option A is the most cost-effective billing method for a 10-day test, as it allows you to enjoy the flexibility of Pay-As-You-Go and the savings of a fixed commitment. References: Billing methods and Savings Plan.

Alibaba Cloud provides comprehensive security protection covering networks, hosts, applications, databases, and content for on-cloud clients, but users still need to pay attention to security protection issues. Alibaba Cloud and its customers are jointly responsible for the security of customers’ applications built on Alibaba Cloud. With security responsibilities shared between Alibaba Cloud and its customers, Alibaba Cloud provides a secure infrastructure to decrease the enterprise security burden of customers. As such, customers can configure and use cloud products in a secure manner, thus relieving much of the underlying security burdens while allowing customers to focus more on their core business needs. However, customers still need to follow the best practices and guidelines for cloud security, such as using strong passwords, enabling multi-factor authentication, encrypting sensitive data, applying security patches, etc. Customers also need to monitor and manage the security risks and incidents of their cloud environment using Alibaba Cloud’s security products and services, such as Security Center, ActionTrail, Cloud Firewall, etc. References: Cloud Security- Alibaba Cloud, Security & Compliance Center, Shared Responsibility

The port 3306 is the default port on which MySQL is usually configured. This port is used by MySQL clients and applications to connect to the MySQL server. If you are using any other port, you should allow traffic to that specific port instead. Alibaba Cloud RDS for MySQL also uses this port by default, unless you specify a different port when creating the RDS instance. You can view and modify the port number of your RDS instance in the RDS console. References: How to configure an Amazon RDS environment for MySQL, Connecting to a DB instance running the MySQL database engine, [Create an ApsaraDB RDS for MySQL instance]