/etc/cloud/cloud.cfg

/etc/cloud/cloud.cfg
preserve_hostname=true

Configuration file '/etc/cloud/cloud.cfg'
==> Modified (by you or by a script) since installation.
==> Package distributor has shipped an updated version.
  What would you like to do about it ?  Your options are:
   Y or I  : install the package maintainer's version
   N or O  : keep your currently-installed version
     D     : show the differences between the versions
     Z     : start a shell to examine the situation
The default action is to keep your current version.
*** cloud.cfg (Y/I/N/O/D/Z) [default=N] ?

See also

• hostnamectl