CNAME used in Global Server Loadbalancing - is it RFC compliant ?
support at gday.ch
support at gday.ch
Wed May 27 03:10:03 UTC 2009
Hello,
we are using Global Server Loadbalancing (GSLB) for site redundancy.
GSLB is based on DNS technology and works as follows
-------------------------------
standard implementation case
-------------------------------
www.example.com. NS loadbalancer-1.example.com.
# --> ( LB located at site-a)
www.example.com. NS loadbalancer-2.example.com.
# --> ( LB located at site-b)
# the loadbalancer (LB) resolves the DNS query for www.example.com, based
# on load balancing criteria with a site specific public IP address
loadbalancer-1.example.com. A 1.y.z.w
loadbalancer-2.example.com. A 2.y.z.w
-------------------------------
?? 'CNAME approach' in question
-------------------------------
(-) Above setup works fine and for each service and we need 2 public IP
addresses one at each site hosted on the loadbalancer device.
(--) now considering that we host the same application with different names
on the same server we need for each one another 2 public IP addresses -
this leads to an unnecessary waste of addresses (x * 2)
==> NEW APPROACH
Instead of using two new IP public addresses for the new service name I
defined following:
new-www.example.com CNAME www.example.com.
==> it works fine so far an the resolve process is as it should be, but
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Is it legitimate (RFC compliant) to use CNAME in this setup or is is just
luck that it works and more compliant resolvers won't work properly ??
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Thanks a lot
Marcel
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