Docker不能启动，ERROR: ZONE_CONFLICT: 'docker0' already bound to a zone

Docker服务意外停止，想要重启Docker服务时，却遇到了 ERROR: ZONE_CONFLICT: 'docker0' already bound to a zone 的错误，解决方案如下：

https://stackoverflow.com/questions/67497455/failed-to-start-docker-daemon-firewalld-docker-zone-already-exists

this works (do all the steps):

1. Check if docker zone exists in firewall-cmd

$ firewall-cmd --get-active-zones

2. If "docker" zone is available, change interface to docker0 (not persisted)

$ sudo firewall-cmd --zone=docker --change-interface=docker0

3. If "docker" zone is available, change interface to docker0 (persisted, thanks rbjorklin)

$ sudo firewall-cmd --permanent --zone=docker --change-interface=docker0
$ sudo systemctl restart firewalld