Alibaba ACA-Cloud1 ACA Cloud Computing Associate Exam Practice Test

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 : 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.

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 : B

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 capacity12Reference:1:Elastic Self-Health2:Enable or disable Elastic Self-Health

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, D

You can create a custom image for ECS using data disk snapshots or system disk snapshots. A snapshot is a backup of the data on a disk at a specific point in time. You can use snapshots to create custom images, which are copies of the operating system and applications on a disk.You can use custom images to create ECS instances that have the same operating system, applications, and data as the original disk12.

You cannot create a custom image for ECS using CPU snapshots or memory snapshots. These are not valid terms in Alibaba Cloud.CPU and memory are not persistent storage devices, and they do not store the operating system and applications that are required for creating a custom image34.Reference:1: Create a custom image from a snapshot - Alibaba Cloud12: What is a custom image?- Alibaba Cloud23: What is a CPU?- Alibaba Cloud34: What is memory?- Alibaba Cloud4

Answer : A, B

You can upgrade or downgrade an ECS instance's configuration to meet your business needs. Upgrading an instance's configuration means increasing the vCPUs, memory, bandwidth, or disk capacity of the instance. Downgrading an instance's configuration means decreasing the vCPUs, memory, bandwidth, or disk capacity of the instance.You can change the configuration of an ECS instance by using one of the following methods1:

Change the instance type: You can change the instance type of an ECS instance to adjust the vCPUs and memory of the instance.You can change the instance type of an ECS instance in the following scenarios2:

The instance is in theStoppedstate and uses apay-as-you-gobilling method.

The instance is in theRunningstate and uses asubscriptionbilling method, and the new instance type belongs to the same instance family as the original instance type.

Change the bandwidth configuration: You can change the bandwidth configuration of an ECS instance to adjust the network performance of the instance.You can change the bandwidth configuration of an ECS instance in the following scenarios3:

The instance is in theStoppedstate and uses apay-as-you-gobilling method, and the instance is not associated with an EIP.

The instance is in theRunningstate and uses asubscriptionbilling method, and the instance is not associated with an EIP.

Change the system disk or data disk: You can change the system disk or data disk of an ECS instance to adjust the disk capacity or performance of the instance.You can change the system disk or data disk of an ECS instance in the following scenarios4:

The instance is in theStoppedstate and uses apay-as-you-gobilling method, and the disk is not encrypted.

The instance is in theRunningstate and uses asubscriptionbilling method, and the disk is not encrypted.Reference:1:Overview of instance configuration changes - Alibaba Cloud2:Change the instance type of an ECS instance - Alibaba Cloud3:Change the bandwidth configuration of an ECS instance - Alibaba Cloud4:Change the system disk or data disk of an ECS instance - Alibaba Cloud.