Hello
Packer can use null builder to connect over ssh to a linux machine and run scripts
but will more to configure after the OS install have started.
Can you share more information on what you do today, and how you think this solution would work?
how you take a copy of 1 server bare metal, and deploy to others?
in my old days as sysadmin. were tools to do that, like Altiris ( then symantec ) rapid deployment , and were included in some suites for say HP servers.
but also you can create custom isos for Linux and Windows that when boot can do a silent installation, however, depending on the features, some task like firmware upgrade, raid configuration/setup need to be done prior the OS install.
these kind of task, in some brands can be automated too with their own software for server management
ie HPE
Some OS have ways to deploy metal, like ubuntu maas
other alternative is what
packet.net now equinix metal have done
Alvaro