MT#4823 remove hosts not available or reply truncated

lib/get_default_pingnodes

@@ -5,7 +5,21 @@
 -%]
 [% PERL -%]
 my $gateway = (split(" ", `ip route | grep default`))[2];
-my @nodes = (split(" ", `grep nameserver /etc/resolv.conf | cut -f2 -d' '|xargs`));
-push(@nodes, $gateway);
+my @nodes = ($gateway);
+my @dnsnodes = (split(" ", `grep nameserver /etc/resolv.conf | cut -f2 -d' '|xargs`));
+
+foreach my $host (@dnsnodes)
+{
+  my $res = `/bin/ping -c 1 -s 164 $host -W 1 2>/dev/null`;
+  if ($res =~ '1 received')
+  {
+    if ($res =~ 'truncated') { print "#$host reply truncated\n"; }
+    else { push(@nodes, $host); }
+  }
+  else
+  {
+    print "# $host error\n";
+  }
+}
 $stash->set(out => \@nodes);
 [% END -%]