diff --git a/perl-xCAT-2.0/xCAT/Schema.pm b/perl-xCAT-2.0/xCAT/Schema.pm
index 49efb26bb..86c6845ec 100644
--- a/perl-xCAT-2.0/xCAT/Schema.pm
+++ b/perl-xCAT-2.0/xCAT/Schema.pm
@@ -381,14 +381,14 @@ servicenode => {
     table_desc => 'List of all Service Nodes and services that will be set up on the Service Node.',
  descriptions => {
   node => 'The hostname of the service node as known by the Management Node.',
-  nameserver => 'Do we set up DNS on this service node? Valid values:yes or 1, no or 0.',
-  dhcpserver => 'Do we set up DHCP on this service node? Valid values:yes or 1, no or 0  We may also support: <ifname>,<noderange>,<dynamicrange>, but this has not been decided yet.',
-  tftpserver => 'Do we set up TFTP on this service node? Valid values:yes or 1, no or 0.',
-  nfsserver => 'Do we set up file services (HTTP,FTP,or NFS) on this service node? Valid values:yes or 1, no or 0.',
-  conserver => 'Do we set up Conserver on this service node? Valid values:yes or 1, no or 0.',
-  monserver => 'Is this a monitoring event collection point? Valid values:yes or 1, no or 0.',
-  ldapserver => 'Do we set up ldap caching proxy on this service node? Valid values:yes or 1, no or 0.',
-  ntpserver => 'Do we set up and ntp server on this service node? Valid values:yes or 1, no or 0.',
+  nameserver => 'Do we set up DNS on this service node? Valid values:yes or 1, no or 0. If blank, means yes.',
+  dhcpserver => 'Do we set up DHCP on this service node? Valid values:yes or 1, no or 0. If blank, means yes.  We may also support: <ifname>,<noderange>,<dynamicrange>, but this has not been decided yet.',
+  tftpserver => 'Do we set up TFTP on this service node? Valid values:yes or 1, no or 0. If blank, means yes.',
+  nfsserver => 'Do we set up file services (HTTP,FTP,or NFS) on this service node? Valid values:yes or 1, no or 0. If blank, means yes.',
+  conserver => 'Do we set up Conserver on this service node? Valid values:yes or 1, no or 0. If blank, means yes.',
+  monserver => 'Is this a monitoring event collection point? Valid values:yes or 1, no or 0. If blank, means yes.',
+  ldapserver => 'Do we set up ldap caching proxy on this service node? Valid values:yes or 1, no or 0. If blank, means yes.',
+  ntpserver => 'Do we set up and ntp server on this service node? Valid values:yes or 1, no or 0. If blank, means yes.',
      comments => 'Any user-written notes.',
      disable => "Set to 'yes' or '1' to comment out this row.",
  },