Not sure what you have as a dns server. But in essence you would make the 2 GSS's authoritative for the x.y.com sub domain. If we take a Bind server as an example you have 2 otions first would be direct delegation of A records to the GSS , in this example I am making GSS authoritative for www.cisco.com
$TTL 3h
cisco.com. IN SOA nameserver1.cisco.com. adminemail.cisco.com. (
2003070801 ; Serial
3h ; Refresh after 3 hours
1h ; Retry after 1 hour
1w ; Expire after 1 week
1h ) ; Negative caching TTL of 1 hour
;
; Name servers
;
cisco.com. IN NS nameserver1.cisco.com.
www.cisco.com. IN NS gss1.cisco.com. ß NS record for www.cisco.com via GSS1
www.cisco.com. IN NS gss2.cisco.com. ß NS record for www.cisco.com via GSS2
;
; Addresses
;
localhost.cisco.com. IN A 127.0.0.1
nameserver1.cisco.com. IN A 10.10.10.1
gss1.cisco.com. IN A 10.1.1.254 ß A record for GSS1
gss2.cisco.com. IN A 10.1.2.254 ß A record for GSS2
The other option is to delegate the subdomain to the GSS's using CNAME
$TTL 3h
cisco.com. IN SOA nameserver1.cisco.com. adminemail.cisco.com. (
2003070801 ; Serial
3h ; Refresh after 3 hours
1h ; Retry after 1 hour
1w ; Expire after 1 week
1h ) ; Negative caching TTL of 1 hour
;
; Name servers
;
cisco.com. IN NS nameserver1.cisco.com.
gslb.cisco.com. IN NS gss1.gslb.cisco.com. ß delegates authority for gslb.cisco.com via GSS1
gslb.cisco.com . IN NS gss2.gslb.cisco.com. ß delegates authority for gslb.cisco.com via GSS2
;
; Addresses
;
localhost.cisco.com. IN A 127.0.0.1
nameserver1.cisco.com. IN A 10.10.10.1
gss1.gslb.cisco.com. IN A 10.1.1.254 ß A record for GSS1
gss2.gslb.cisco.com. IN A 10.1.2.254 ß A record for GSS2
;
; Aliases
;
www.cisco.com. IN CNAME www.gslb.cisco.com. ß client can use either name
attaching a somewaht dated best practices document however the points remain valid.
