shorten timeout on dns for timeoutdevices report

lib/App/Netdisco/Util/DNS.pm

@@ -105,7 +105,7 @@ sub ipv4_from_hostname {
   return undef;
 }
 
-=head2 hostnames_resolve_async( $ips )
+=head2 hostnames_resolve_async( \@ips, \@timeouts? )
 
 This method uses a fully asynchronous and high-performance pure-perl stub
 resolver C<AnyEvent::DNS>.
@@ -114,14 +114,21 @@ Given a reference to an array of hashes will resolve the C<IPv4> or C<IPv6>
 address in the C<ip>, C<alias>, or C<device> key of each hash into its
 hostname which will be inserted in the C<dns> key of the hash.
 
+Optionally provide a set of timeout values in seconds which is also the
+number of resolver attempts. The default is C<< [2,5,5] >>.
+
 Returns the supplied reference to an array of hashes with dns values for
 addresses which resolved.
 
 =cut
 
 sub hostnames_resolve_async {
-  my $ips  = shift;
+  my ($ips, $timeouts) = @_;
+  return [] unless $ips and ref [] eq ref $ips;
+  $timeouts ||= [2,5,5];
+
   my $skip = setting('dns')->{'no'};
+  AnyEvent::DNS::resolver->timeout(@$timeouts);
 
   # Set up the condvar
   my $done = AE::cv;
@@ -151,6 +158,7 @@ sub hostnames_resolve_async {
   $done->recv;
   
   # Remove reference to resolver so that we close sockets
+  # and allow return to any instance defaults we have changed
   undef $AnyEvent::DNS::RESOLVER if $AnyEvent::DNS::RESOLVER;
 
   return $ips;