This is a quick guide to backing up and restoring your ESXi host (based around ESXi 6.7) using PowerCLI

Backup

To backup your host’s configuration run:

Get-VMHostFirmware -VMHost 10.50.0.10 -BackupConfiguration -DestinationPath C:\ESXiBackups

Restore

To restore your host’s configuration, first install ESXi on the host, give it an IP then put it in maintenance mode:

Set-VMHost -VMHost 10.50.0.10 -State 'Maintenance'

Then restore the backup file to the host:

Set-VMHostFirmware -VMHost 10.50.0.10 -Restore -SourcePath C:\ESXiBackups\bundleToRestore.tgz -HostUser root -HostPassword yourrootpassword