ACP-Cloud1 Exam Dumps - Alibaba Cloud Computing Questions and Answers

The DNS service provider used by the domain name (such as abc.com) does not need to support intelligent resolution, because the CNAME address allocated to the domain name will point to an IP address that is intelligently managed by Alibaba Cloud CDN system. Therefore, option C is not a correct description of modifying domain name resolution. References: What is Alibaba Cloud CDN? - CDN - Alibaba Cloud Documentation Center and Alibaba Cloud CDN

Auto Scaling in Alibaba Cloud supports both Pay-As-You-Go and monthly subscription ECS instances within a scaling group. Pay-As-You-Go instances provide flexibility during traffic surges, while idle monthly subscription instances can be added manually to optimize costs and resource usage.

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 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. 

Alibaba Cloud OSS ensures high reliability and availability by maintaining multiple copies of data across different physical locations, allowing it to recover within minutes in the event of hardware failures. This redundancy mechanism provides strong data durability and service continuity.

During cool-down time, scaling activities in the same scaling group are temporarily locked to avoid unnecessary scaling activities. The cool-down time begins once all ECS instances in a multi-instance scaling action are added or removed.

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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.

With a measurement cycle of 5 minutes and a requirement for five consecutive cycles where disk usage exceeds 80%, it would take 5×5=255 \times 5 = 255×5=25 minutes for CloudMonitor to confirm the condition. After confirmation, CloudMonitor typically processes and sends the alert, which may take an additional 5 minutes, totaling approximately 30 minutes before you receive the alert.

Using lifecycle hooks in Auto Scaling allows for custom operations, such as updating the Redis whitelist when instances are added or removed. An OOS (Operation Orchestration Service) template can automate this process, and MNS (Message Notification Service) can trigger events to inform Redis when changes occur.

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Alibaba Cloud OSS (Object Storage Service) is designed for storing large volumes of unstructured data, such as files, images, and videos, making it an optimal solution for network disk applications. By migrating storage from ECS data disks to OSS, the team can offload storage tasks, reduce the number of ECS instances required, and significantly lower O&M costs. OSS also provides high scalability, reliability, and cost-effectiveness for such use cases.

Alibaba Cloud Elastic Compute Service (ECS) instances in different security groups are isolated from each other by default, but they can communicate with each other if the security group rules allow it. A security group is a virtual firewall that controls the inbound and outbound traffic of ECS instances. You can configure security group rules to specify which IP addresses, protocols, and ports can access the ECS instances in a security group. You can also authorize other security groups to access the ECS instances in a security group, which enables cross-security group communication. References: Manage ECS instances in security groups, Security FAQ, ECS Security Groups - Alibaba Fundamentals