Incorrect.

Machine IDs are stored in several places, some of which are not even files.

* http://jdebp.uk./Softwares/nosh/guide/commands/machine-id.xm...

They can be resurrected if not all storage locations are dealt with. Moreover, some systems use things like the SMBIOS product UUID.

* http://jdebp.uk./Softwares/nosh/guide/commands/setup-machine...

The correct approach is not deleting files.

* http://jdebp.uk./Softwares/nosh/guide/commands/erase-machine...

* https://lists.debian.org/debian-user/2019/03/msg00550.html

Thanks.

So at boot, one would run "erase-machine-id". Then create a random 30-character hexadecimal number. And then either set "the systemd.machine_id= kernel command line parameter" to it. Or pass it via "the option --machine-id= to systemd".

No.

    % system-control cat machine-id
    start:#!/bin/nosh
    start:true
    stop:#!/bin/nosh
    stop:envdir env
    stop:erase-machine-id
    run:#!/bin/nosh
    run:#Set up and tear down the machine ID
    run:envdir env
    run:setup-machine-id
    restart:#!/bin/sh
    restart:exec false      # ignore script arguments
    %

OK, thanks.

So "setup-machine-id". Does that generate a value that's unrelated to any preexisting versions, analogs, etc?

I ask because, when I deleted /etc/machine-id and ran "systemd-machine-id-setup", it generated a new machine-id by copying the D-Bus machine ID.

I'll test that.

Edit: OK, so I created a Debian VM, noted /etc/machine-id, deleted it, and rebooted. And found that it was still missing.

Running systemd-machine-id-setup generated a new machine-id from the D-Bus machine ID. And it was the same as the initial one.

But I also see in man machine-id:

> The machine-id may also be set, for example when network booting, by setting the systemd.machine_id= kernel command line parameter or passing the option --machine-id= to systemd. A machine-id may not be set to all zeros.

Does something like

dd if=/dev/urandom bs=1 count=16 | hexdump

Give you something that you can use?

Well, the machine-id of that Debian VM was ...

    38d05397c25548b4f4bda7751b5062

... and ...

    $ FOO=`cat /dev/urandom | tr -dc a-z0-9 | head -c${1:-30}`
    $ echo $FOO
      6we4gvnmx00w208ffty6i11m82rw6d

But I have no clue whether systemd would be happy with that. Maybe later I can test more.

Edit: Oops. Make that ...

    $ FOO=`cat /dev/urandom | tr -dc abcdef0-9 | head -c${1:-30}`
    $ echo $FOO
      b486935dbb9e9fe603328a19e2b5b4

Maybe use pwgen?

Something like:

    $ pwgen -1s 31
    qHfKU46H2RA2WUr0EZ1zBHfIBLKZKuT

I think that it needs to be hexadecimal. But not sure.

No worries. :)