Pass the Alibaba Cloud Computing ACP-Cloud1 Questions and answers with ExamsMirror

To enable Internet access for ECS instances in a VPC, Alibaba Cloud users can use a public SLB with an Internet IP address (Option B) or an SLB with an Elastic IP (EIP) attached (Option C). Both methods allow the SLB instance to receive external requests and forward them to ECS instances within the VPC. Option A is incorrect because it would require a more complex setup without direct Internet access. Option D is incorrect as SLB does not support directly mounting servers from an on-premises data center.

 Changing an instance’s operating system requires creating a custom image or using a public image, and then replacing the system disk of the instance. This process will cause the instance to restart. Therefore, this statement is false. References: ECS User Guide: Replace the system disk (non-public image) and ECS User Guide: Replace the system disk (public image)

In Alibaba Cloud, a scaling group can be associated with multiple SLB instances as long as they are in the same region, allowing distributed load handling across multiple load balancers. However, there is no requirement for SLB instances or scaling configurations to be in the same zone, making it region-specific instead of zone-specific.

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By default, ECS instances in different zones within the same region are not interconnected via the Intranet. To enable communication between instances across zones, you would need to configure a VPC or use other network configurations. This setup provides isolation and flexibility in managing network traffic within different zones.

Data Transmission Service (DTS) is a real-time data streaming service that supports data transmission between data sources such as relational databases, NoSQL, and Big Data (OLAP). DTS supports data migration, data synchronization, and change data subscription scenarios. DTS can migrate your data to and from most of the widely used commercial and open source databases. It supports homogeneous migrations such as MySQL to MySQL, as well as heterogeneous migrations between different database platforms, such as Oracle to MySQL. Migrations can be from on-premises databases to RDS or ECS, databases running on ECS to RDS, or vice versa, as well as from one RDS database to another RDS database. DTS also supports database schema replication between instances, which means that DTS can automatically create the same schema as the source database in the target database. DTS also supports warning when source and destination has some unresolved conflict found, such as data type mismatch, primary key conflict, or foreign key constraint violation. DTS can help you resolve these conflicts by providing suggestions or allowing you to modify the data mapping rules. Therefore, the correct answer is C. Supports all of the above functions. References:

1: Data Transmission Service - Alibaba Cloud

2: What is Data Transmission Service? - Alibaba Cloud

3: Database Migration - AlibabaCloud

4: Cloud Migration without Stopping Services: Alibaba Cloud DTS

In Alibaba Cloud RDS, multiple databases can be created within a single instance, allowing users to manage different databases under one RDS instance efficiently. However, databases within the same instance must have unique names, and resources such as CPU and memory are shared across databases within the same instance, contrary to the options provided in answers B and C.

Before data communication is set up, the security groups match the security group rules one by one to query whether to allow access requests. If the protocol type, port range, authorization type, and authorization object of two security group rules are the same, the following rules apply:

If the two rules have the same priority, the rule of the denial policy takes effect first, and the rule of the allowed policy does not take effect. This is because the security group rules follow the principle of minimum permission, which means that the most restrictive rule is applied when there is a conflict.

If the two rules have different priorities, the rule with a smaller priority number takes effect. This is because the security group rules follow the principle of priority, which means that the rule with a higher priority (lower number) is applied when there is a conflict. References: ECS Security Groups - Alibaba Fundamentals - Cloud Academy, Security group rules - Elastic Compute Service - Alibaba Cloud Documentation Center

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]

Alibaba Cloud RDS supports several popular database engines, including MySQL, PostgreSQL, and SQL Server. PPAS (PostgreSQL Plus Advanced Server) is also supported but not Sybase, which is not available as an RDS option on Alibaba Cloud.

Alibaba Cloud SLB can distribute user requests to backend ECS instances, but these ECS instances do not have to have the same specification (CPU, Memory). SLB virtualizes the added group of ECS instances in the same region into an application pool, and you can manage backend servers through either the default server group, a primary server group, or VServer groups. You can add ECS instances of different specifications to the same server group or VServer group according to your needs. SLB supports weighted round-robin (WRR) and weighted least connections (WLC) algorithms to balance the load among backend servers with different weights. References:

SLB overview - Alibaba Cloud

Backend server overview - Alibaba Cloud

What is Server Load Balancer and How It Works - Alibaba Cloud

Server Load Balancer - Alibaba Cloud

Alibaba Server Load Balancer (SLB) Course - Cloud Academy