ACA-Cloud1 ACA Cloud Computing Associate Questions and Answers

OSS object types are the storage classes that define the performance and cost of storing objects in OSS. OSS supports four object types: Standard, Infrequent Access (IA), Archive, and Cold Archive1. Each object type has different characteristics and scenarios, such as availability, durability, minimum storage duration, and storage overhead2.

Object lifecycle management is a feature that allows you to manage objects efficiently and minimize costs throughout the lifecycle of the objects in your bucket. Lifecycle settings create a set of rules that help define the actions that an OSS bucket must perform on a group of objects. For example, you can configure lifecycle rules to automatically delete expired objects, or convert the storage class of objects to a lower-cost object type3.

You can configure lifecycle rules based on the object type of the objects in your bucket. You can specify the object type as a parameter for the lifecycle rule, and OSS will apply the rule to the objects that match the object type. For example, you can create a lifecycle rule to convert the object type of objects from Standard to IA after 30 days, and then to Archive after 180 days4.

Therefore, the correct answer is A. Infrequent access and C. Archive, as these are two of the object types that can be configured as parameters for object lifecycle management. B. Snapshot and D. Chunk are not valid object types in OSS. References: 1: Overview of object types - Object Storage Service - Alibaba Cloud Documentation Center2: Object Storage Service (OSS) - Alibaba Cloud3: Manage Your OSS Storage Costs Using Lifecycle Policies - Alibaba Cloud4: Lifecycle rules based on the last modified time - Object Storage Service - Alibaba Cloud Documentation Center.

 B is the correct answer because Auto Scaling can automatically remove unhealthy ECS instances from the scaling group, and also automatically add equivalent amount of new ECS instances back to the scaling group. This feature is called Elastic Self-Health, and it can improve the availability and reliability of the scaling group. Elastic Self-Health can be enabled or disabled in the scaling group settings. When Elastic Self-Health is enabled, Auto Scaling monitors the health status of the ECS instances in the scaling group based on the health check results of the Server Load Balancer (SLB) instances that are associated with the scaling group. If an ECS instance is detected as unhealthy by SLB for a specified period of time, Auto Scaling removes the unhealthy ECS instance from the scaling group and releases it. Then, Auto Scaling triggers a scale-out event to add a new ECS instance to the scaling group to maintain the desired capacity12 References: 1: Elastic Self-Health 2: Enable or disable Elastic Self-Health

Auto Scaling is a management service that can automatically adjust elastic computing resources based on your business needs and policies. It can help you cope with traffic spikes, reduce costs, and improve service availability1. Auto Scaling supports adding an existing ECS instance into the scaling group, which is a collection of ECS instances that share the same scaling configuration and scaling rules2. However, the existing ECS instance must meet certain requirements, one of which is that the instance and the scaling group must be in the same region3. A region is a physical location where Alibaba Cloud deploys its data centers. Each region consists of multiple isolated zones that have independent power grids and networks4. Therefore, the instance and the scaling group do not have to be in the same zone, as long as they are in the same region.

References: 1: Alibaba Cloud Academy, “Auto Scaling”, https://edu.alibabacloud.com/elearning/lesson/ACA-Cloud-Computing-Certification/lesson-6-auto-scaling  2: Alibaba Cloud, “Scaling group”, https://www.alibabacloud.com/help/doc-detail/25948.htm  3: Alibaba Cloud, “Add an existing ECS instance to a scaling group”, https://www.alibabacloud.com/help/doc-detail/25949.htm  4: Alibaba Cloud, “Regions and zones”, https://www.alibabacloud.com/help/doc-detail/40654.htm

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

 According to the Alibaba Cloud Academy, Alibaba Cloud’s object storage service (OSS) is a cloud storage service that enables you to store, backup, and archive any amount of data in the cloud. OSS is a cost-effective, highly secure, and highly reliable cloud storage solution. The capacity of each bucket is unlimited, and there is no limit on the number of files in a single bucket. Therefore, the statement is false. References: What is OSS? - Alibaba Object Storage Service Course - Cloud Academy, Object Storage Service(OSS): Store Data Safely In The Cloud - Alibaba Cloud Blog

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.

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

Your website has oscillating traffic peaks that are difficult to predict in advance. In this scenario, it is recommended to use SLB and Auto Scaling together with ECS. SLB 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. Auto Scaling is a service that automatically adjusts computing resources based on your volume of user requests. When the demand for computing resources increases, Auto Scaling automatically adds ECS instances to serve additional user requests, or alternatively removes instances in the case of decreased user requests. By using SLB and Auto Scaling together with ECS, you can achieve high scalability and elasticity for your website, and cope with the changing traffic patterns12. References: 1: ACA Cloud Computing Exam Preparation Course - Alibaba Cloud3 2: Auto Scaling: Automatically Adjusts Computing Resources - Alibaba Cloud4

Auto Scaling is a service that automatically adjusts computing resources based on your volume of user requests. When the demand for computing resources increases, Auto Scaling automatically adds ECS instances to serve additional user requests, or alternatively removes instances in the case of decreased user requests1. Auto Scaling can help you manage traffic peaks efficiently and maintain a consistent user experience by scaling up or down your ECS instances according to your predefined policies and business needs2. References: 1: Auto Scaling: Automatically Adjusts Computing Resources - Alibaba Cloud2: Overview - Auto Scaling - Alibaba Cloud Documentation Center.

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. References: 1: ACA Cloud Computing Exam Preparation Course - Alibaba Cloud3 2: Server Load Balancer - Alibaba Cloud Documentation Center4

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

 Elastic Compute Service (ECS) is an IaaS offering on Alibaba Cloud that provides high-performance, stable, reliable, and scalable compute capacity in the cloud. ECS eliminates your need to invest in hardware up front. You can create as many or as few instances as you need in response to changes in requirements or popularity of your workloads. With an ever-growing selection of instance types, ECS provides broader and deeper choices to match a wide spectrum of computing needs. References: What is ECS? - Alibaba Cloud

A bucket is a container for objects in Object Storage Service (OSS). Every user can create more than one bucket, but every bucket should have a unique name in OSS. There is no limitation to the number of objects inside one bucket. However, the bucket name cannot be changed after creation. You cannot customize, change, or request a namespace name change1. If you want to modify an object, you must upload a new object with the same name as the existing one to replace it2. References: 3: Create a bucket - Object Storage Service - Alibaba Cloud3 4: Manage objects in a versioning-enabled bucket - Object Storage Service - Alibaba Cloud4 1: Understanding Object Storage Namespaces - Oracle1 2: OSS Concepts - Alibaba Object Storage Service Course - Cloud Academy2

 A company wants to use Alibaba Cloud service to replace their self-built database, which of the following services should it choose? The best answer is ApsaraDB for RDS, which is a stable, reliable, cost-effective, and scalable online database service that supports most mainstream database engines, including MySQL, SQL Server, PostgreSQL, PPAS (highly compatible with Oracle), and MariaDB1. ApsaraDB for RDS is based on the Apsara Distributed File System and high-performance SSDs of Alibaba Cloud, and provides various features such as backup and recovery, performance monitoring, security, and disaster recovery2. By using ApsaraDB for RDS, the company can reduce the complexity and cost of database management, and focus on their core business.

The other options are not suitable for replacing a self-built database. Server Load Balancer (SLB) 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 applications3. Alibaba Cloud CDN (Content Delivery Network) is a service that delivers content from origin servers to edge nodes, and accelerates the response to user requests. It can be used to improve the user experience and reduce the bandwidth consumption of origin servers4. Deploying more ECS instances is a way to increase the computing resources and scalability of applications, but it does not provide a database service5. References: 1: What is ApsaraDB RDS? - ApsaraDB RDS - Alibaba Cloud1 2: ApsaraDB RDS:What is ApsaraDB RDS? - Alibaba Cloud2 3: Server Load Balancer - Alibaba Cloud Documentation Center3 4: Alibaba Cloud CDN - Alibaba Cloud4 5: Elastic Compute Service (ECS) - Alibaba Cloud5

 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

 Web Application Firewall (WAF) is a cloud-based security service that protects web applications from common web attacks, such as SQL injection, cross-site scripting, and HTTP flood. WAF can also filter out malicious requests and bots, and ensure that only legitimate traffic reaches the web servers. WAF can help online shops to avoid HTTP flood attacks and ensure only genuine customers joining the event.

References:

• Alibaba Cloud Web Application Firewall
• ACA Cloud Computing Certification Exam Preparation Course
• Alibaba Cloud Computing Exam Question 2022

After adding your website to the WAF protection list, you can enable HTTP Flood protection and select an appropriate protection mode for the website

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

Alibaba Cloud Monitor service is a service that monitors the running status of Alibaba Cloud resources and custom metrics, and provides alert notifications and data visualization features. A user receives an alert saying that the IOPS utilization rate for an ECS instance exceeds 80%, which means that the disk performance of the instance is reaching its limit and may affect the application performance. To handle the situation, the user may obtain help from Alibaba Cloud through the following methods:

• Check ECS or CloudMonitor product documents: The user can check the official documentation of ECS or CloudMonitor to learn more about the concepts, features, operations, and best practices of these services. For example, the user can find the information about how to view the IOPS utilization rate of an ECS instance, how to optimize the disk performance of an ECS instance, and how to configure alert rules for CloudMonitor.
• Open a ticket to Alibaba Cloud help desk: The user can open a ticket to Alibaba Cloud help desk to get technical support from Alibaba Cloud engineers. The user can choose the ticket type, severity, and product, and describe the problem in detail. The user can also attach screenshots or logs to the ticket to help the engineers diagnose the problem. The user can track the status and response of the ticket in the console.
• Look for answers in Alibaba Cloud forum: The user can look for answers in Alibaba Cloud forum, which is a platform where Alibaba Cloud users can share their experiences, ask questions, and discuss topics related to Alibaba Cloud products and services. The user can search for relevant keywords or tags, browse the existing threads, or post a new question in the forum. The user can also interact with other users or Alibaba Cloud experts in the forum.

D. You cannot obtain any help from Alibaba Cloud is not a correct answer, as Alibaba Cloud provides various ways to help its users with their problems and questions. References: : [What is CloudMonitor? - CloudMonitor - Alibaba Cloud Documentation Center]. : [View the IOPS utilization of an ECS instance - CloudMonitor - Alibaba Cloud Documentation Center]. : [Optimize the disk performance of an ECS instance - Elastic Compute Service - Alibaba Cloud Documentation Center]. : [Configure alert rules - CloudMonitor - Alibaba Cloud Documentation Center].