Elastic IP (EIP): an EIP is a static IP address designed for dynamic cloud computing. It is also a public IP address that remains unchanged in a region. With EIPs, you can quickly remap an address to another instance or a NAT gateway instance under your account to shield instance failures. You can keep the EIP under your account until it is released. While the public IP can only be released with the CVM, the EIP can be decoupled from the CVM lifecycle and operate independently as a cloud resource. For example, if you need to retain a public IP that is strongly related to your business, you can convert it into an EIP and keep it under your account.
For the step-by-step operations of EIPs, see the “Directions” section in Elastic IP.