Once our hosts have been configured, it is advisable to keep a backup copy of their configuration, an easy way to back up the entire configuration of an ESXi host is by using the appliance VMware vMA or through VMware vSphere CLI (vCLI). Once we have the backup, we can restore it if necessary in a simple way, we will also see another command to reset ESXi hosts to factory values.

To back up a host's configuration we will run: 'vicfg-cfgbackup -s server HOST_ESX_ORIGEN /PATH/BACKUP’

To restore just run: 'vicfg-cfgbackup -l server HOST_ESX_DESTINO /PATH/BACKUP’

If we run 'vicfg-cfgbackup -r server HOST_ESX’ we can reset an ESXi host to its default values losing all kinds of configuration.