zgenhostid — generate host ID into /etc/hostid

       Creates  /etc/hostid  file and stores the host ID in it.  If hostid was provided, validate and store that
       value.  Otherwise, randomly generate an ID.

       Generate a random hostid and store it
                 #zgenhostid

       Record the libc-generated hostid in /etc/hostid#zgenhostid "$(hostid)"

       Record a custom hostid (0xdeadbeef) in /etc/hostid#zgenhostiddeadbeef

       Record a custom hostid (0x01234567) in /tmp/hostid and overwrite the file if it exists
                 #zgenhostid-f-o/tmp/hostid0x01234567

/etc/hostid

zgenhostid  emulates the genhostid(1) utility and is provided for use on systems which do not include the
       utility or do not provide the sethostid(3) function.

OpenZFS                                           May 26, 2021                                     ZGENHOSTID(8)

       zgenhostid — generate host ID into /etc/hostid

-h           Display a summary of the command-line options.

       -f           Allow output overwrite.

       -ofilename  Write to filename instead of the default /etc/hostid.

       hostid       Specifies the value to be placed in /etc/hostid.  It should be a number with a value between
                    1 and 2^32-1.  If 0, generate a random ID.  This value must be unique  among  your  systems.
                    It must be an 8-digit-long hexadecimal number, optionally prefixed by "0x".

genhostid(1), hostid(1), sethostid(3), spl(4)

zgenhostid [-f] [-ofilename] [hostid]