GSLB and ADNS

[William]

I'm migrating a VPX to a new platform and want to use a gradual migration method.  I want to bring over a batch of virtual servers, one batch at a time until the old VPX is no longer in use.  Some of these virtual servers have GSLB services tied to them.  We use active/passive GSLB.  I've setup the new VPX (which is replacing the current active site VPX) with a new site ID and have added the passive remote site.  I've created a new ADNS service with a unique IP owned by the new VPX.  I'd like to add this ADNS service as a DELG record so that it can answer CNAME queries forwarded to it for virtual servers I've moved from legacy to it.  For a virtual server with GSLB being moved, I would disable the virtual server and remove the GSLB related config for that server.  The new VPX would then be configured to support GSLB for the virtual server and have the corresponding address record on it, as would the passive remote VPX.  So I guess I have 2 questions.  How sound is this method of migration and what might happen if I add the new DELG record and the new VPX/ADNS server is permitted to answer queries for GSLB services I haven't moved to it yet?  Would the client be unable to resolve the DNS record or would the legacy VPX be queried next and provide the resolution? 

 

thank you

[TD343212]

Once you have your configuration created on your new VPX, I would simply remove the DNS delegation for the VIP you want to move and recreate it using the new ADNS IPs.  This is very clean, and quick, especially if you use dnscmd commands.  It would be very easy to flip back if you had an issue.

For example, to create a delegation using dnscmd for web.domain.local, use the following:

dnscmd 1.1.1.1 /RecordAdd domain.local web 5 CNAME web.gslb.domain.local

dnscmd 1.1.1.1 /RecordAdd domain.local web.gslb 5 NS gslb-adns1.domain.local
dnscmd 1.1.1.1 /RecordAdd domain.local web.gslb 5 NS gslb-adns2.domain.local

If you use a subdomain like in this example, be careful to include the web.gslb when adding the delegation.... if you just put gslb, it will overwrite the entire sub domain.