my %connecting = map { $_ => 1 } @hosts;
while (1) {
  for my $host (keys %connecting) {
    my $ssh = $ssh{$host};
    if ($ssh->wait_for_master(1)) {
      delete $connecting{$host};
    }
    elsif ($ssh->error) {
      # handle connection error
      delete $connecting{$host};
    }
  }
  last unless %connecting; 
  select (undef, undef, undef, 0.05);
}