If an ECS instance in a VPC needs to provide external services, you can allocate a public IP for it when creating the ECS instance.
As shown in the following figure, after you have chosen the VPC and VSwitch where the ECS instance is created, you have to set a network bandwidth peak. The value must be larger than 0 so that a public IP will be allocated to the ECS instance after it is created.
Only when the specified network bandwidth peak is larger than 0, a public IP will be allocated. Otherwise, no public IP is allocated. In this situation, you can bind an EIP to the ECS instance.
You cannot unbind the system allocated IP from the ECS instance.
After the ECS instance is created, you can view the public IP on the Instance List page. You can resolve this public IP to a domain name to provide external services.