Migrate Windows Server 2003 x86 SP2 to windows Server 2012

i want migrate windows 2003 windows server 2012 

primary dc (site1): windows server 2003 sp2 x86 (also dhcp server)
additional dc(site2) : windows server 2008 r2 x64(also dhcp server).

want install windows server 2012 on site1 , make primary domain controller hostname same windows server 2003 , same old ip 

please refer blogs , guide me how achive it.


step1 : 
http://blogs.technet.com/b/canitpro/archive/2013/05/05/step-by-step-adding-a-windows-server-2012-domain-controller-to-an-existing-windows-2003-network.aspx

step2: 
http://blogs.technet.com/b/canitpro/archive/2013/05/27/step-by-step-active-directory-migration-from-windows-server-2003-to-windows-server-2012.aspx

step3: how rename windows server 2012 domain controller (after promoting windows server 2012 primary demote windows server 2003 and i need rename windows server 2012 hostname old hotname , change old ip)

if rename domain controller face issues dns.

step 4 : how export dhcp window server 2003 windows server 2012.

netsh dhcp server export c:\dhcpexport.txt all

netsh dhcp sever import c:\dhcpexport.txt all

exporting txt file best practice?

the best thing can make image of existing dc, , restore image second machine not connected rest of network, handful of test computers belonging network.

verify clients still work (in terms of ad) restored dc.

take information think need , write down / copy-paste lengthy step step document can use make sure need do, in right order.

perform installation procedure create 2012 dc in network , verify clients still work. after you've tested need test , updated installation review comments, execute on live system after taking necessary backups.

other high level information , guidelines, none of here can give detailed plan of action because each situation different , need test need in situation.

test, test, test, , can upgrade. don't want try without having done on offline test system first.

Windows Server  >  Directory Services