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

When the black hole policy is triggered by excessive DDoS traffic, the affected server is temporarily isolated from the network to prevent further damage. During this period, no services are available, meaning the server cannot provide limited-speed services.

Alibaba Cloud Object Storage Service (OSS) is ideal for storing unstructured data, including media files such as pictures, videos, and documents. OSS offers scalable storage, high durability, and easy access, making it well-suited for handling large volumes of unstructured data.

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For optimal use of SLB with Auto Scaling, enabling Health Check is essential to determine which instances are healthy and ready to handle traffic. SLB doesn’t require all backend servers to have the same OS, be in the same scaling group, or have identical configurations, as it can manage heterogeneous server setups within the same load-balancing group.

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Once a VPC is created in Alibaba Cloud, its CIDR Block cannot be modified. This design ensures stability and network consistency within the VPC. To change the network range, a new VPC would need to be created with the desired CIDR Block.

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RDS accounts can be used to connect with the databases created on a given RDS instance. Each account can be bound with multiple databases. However, the read/write permissions of each database can be assigned to multiple RDS accounts, not just one. For example, you can create an account with read-only permission for all databases, and another account with read-write permission for a specific database. This way, you can manage the access control of your databases more flexibly and securely. References:  Introduction to ApsaraDB RDS - Alibaba Cloud Document Center - User Management - Account Permissions

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

For Layer-4 SLB using TCP, the health check determines ECS instance availability based on the successful completion of a TCP 3-way handshake. This ensures that the backend server is reachable and can accept connections, which is critical for reliable TCP-based load balancing.

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Alibaba Cloud Cloud Disks are zone-specific and can only be attached or detached between ECS instances within the same zone and under the same account. This restriction ensures low-latency access and high data availability within the specific zone. Before use, Cloud Disks must be formatted and mounted on an instance.

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Default VPCs do count toward your overall VPC quota in Alibaba Cloud, contrary to option D. Each region has a single default VPC that is automatically created by Alibaba Cloud, and users can create additional VPCs, which are then labeled as non-default VPCs. Default VPCs also have different constraints and operational characteristics compared to user-created VPCs, such as specific configurations for ease of use in basic setups.

Active/standby server groups are a feature of Server Load Balancer (SLB) that allows you to configure a primary ECS instance and a secondary ECS instance for the backend of an SLB instance1. When the primary instance is working properly, the traffic is only forwarded to the primary ECS. When the primary instance is down, traffic is switched to the standby instance1. This feature is supported by TCP and HTTPS listeners, but not by HTTP and UDP listeners1. TCP and HTTPS listeners support session persistence, which ensures that requests from the same client are always forwarded to the same backend server2. HTTP and UDP listeners do not support session persistence, and they use round-robin or weighted round-robin algorithms to distribute traffic among the backend servers2. References: 1: Create an active/standby server group 2: [Configure a listener]