cloudinit: pass through hostname via fqdn field

If no FQDN is provided, we simply set it to the current hostname. This
ensures that the hostname *really* gets set, since we encountered an
issue on Fedora and CentOS based systems where no hostname got set at
all.

When there's no FQDN set in the cloudinit config, this leads to the
following entry:

    127.0.1.1 <hostname> <hostname>

Which doesn't seem to cause any issues.

Tested on:
 - Ubuntu 23.04
 - CentOS 8
 - Fedora 38
 - Debian 11
 - SUSE 15.4

Signed-off-by: Leo Nunner <l.nunner@proxmox.com>

diff --git a/PVE/QemuServer/Cloudinit.pm b/PVE/QemuServer/Cloudinit.pm
index 10962b507820bad81cc437b6e91e772300a45628..cd5cc242db64e3bfa23fdf379b413b47077bd8dd 100644 (file)
--- a/PVE/QemuServer/Cloudinit.pm
+++ b/PVE/QemuServer/Cloudinit.pm
@@ -87,6 +87,8 @@ sub get_hostname_fqdn {
        $hostname =~ s/\..*$//;
     } elsif (my $search = $conf->{searchdomain}) {
        $fqdn = "$hostname.$search";
+    } else {
+       $fqdn = $hostname;
     }
     return ($hostname, $fqdn);
 }
@@ -120,7 +122,7 @@ sub cloudinit_userdata {
 
     $content .= "hostname: $hostname\n";
     $content .= "manage_etc_hosts: true\n";
-    $content .= "fqdn: $fqdn\n" if defined($fqdn);
+    $content .= "fqdn: $fqdn\n";
 
     my $username = $conf->{ciuser};
     my $password = $conf->{cipassword};