Generally, in order to ensure the stable operation of a high-concurrency business, the business is distributed on multiple CVM instances for them to share the pressure, and the same VPC can be established for such instances to enable mutual access between them at private IPs. However, when an instance is switched, its private IP will also change accordingly. Therefore, it is necessary to modify the business code and release the change, which is extremely inconvenient.
In this case, you can create a private domain name for each instance in your VPC through Private DNS and add DNS records pointing to the corresponding private IPs. The instances can access each other at the private domain names, and when an instance is switched, you do not need to modify the code. Instead, you can simply modify the DNS record of its domain name.