Alibaba Cloud Certified Associate (ACA) 2025 – 400 Free Practice Questions to Pass the Exam

The reason a newly created ECS instance might not have a public IP assigned after using the API method 'CreateInstance' is that the developer did not call the method 'AllocatePublicIPAddress' specifically required to assign a public IP. In Alibaba Cloud, when you create an instance, the API does not automatically allocate a public IP for the instance; it must be explicitly requested through this separate call.

Thus, if the API call to allocate a public IP is omitted, the instance will only have a private IP within the network and will not be accessible from the public internet unless additional steps are taken. This highlights the importance of understanding the specific functions and calls needed when working with cloud infrastructure APIs, especially regarding network configurations.

While it’s true that an instance created in a private VPC may inherently not have a public IP due to the nature of that VPC, the fundamental issue here stems from not invoking the allocation command. Similarly, forgotten settings or limitations based on instance type pertain to contextual scenarios but do not specifically address the mechanics of obtaining a public IP upon instance creation.