Ubuntu 18.04 changes the IP address

My memory is getting worse and worse, just recording it. I have done it before, but forgot it after a while. In addition, I use CentOS most often, but many friends prefer Ubuntu or Debian. Today I encountered a cloud host with Ubuntu 18.04 system that changed its IP. The normal change of /etc/network/interfaces did not work. I record it here to avoid the trouble of going to Bing every time.

Ubuntu 18.04 uses Netplan to configure IP addresses, so you need to modify the /etc/netplan/* file.

The above picture shows the modification of /etc/network/interfaces. After the completion of the restart, the new IP is not accessible. Use the ifconfig command to check that it is still the old IP. Next, modify the yaml file under /etc/netplan/. The file name may be different.

Correct the addresses and gateway in the file, save it after completion, and then use sudo netplan apply to apply the configuration.