Alibaba Cloud Certified Associate (ACA) Practice Test 2025 – Complete All-in-One Guide for Exam Success!

Assigning a public IP to an Elastic Compute Service (ECS) instance in Alibaba Cloud typically requires the use of a specific API call designed to allocate a public IP address. The correct choice involves the API call that performs this essential function.

Allocating a public IP address is a critical step after creating an ECS instance. By invoking the designated API, you are able to request and subsequently assign an elastic IP (EIP) or a public IP address to your ECS instance, enabling it to be accessible over the internet. This is particularly important for instances that need to serve web applications, databases, or any services that need to be reachable externally.

In contrast, other options listed do not serve the purpose of allocating a public IP. For instance, creating a network interface is important for networking purposes but does not specifically handle public IP allocation. Associating an EIP is a different process that usually occurs after an EIP is already allocated. Attaching public access may indicate allowing public access to an instance but does not directly assign a public IP.

Thus, when looking to assign a public IP immediately after the creation of an ECS instance, the appropriate API call to use is the one that specifically handles the allocation of the public IP address.