Maybe I didn't say it. In my network I have maybe 5% Windows machines. Most of OSX and Linux, then with AD is not working for me. But I figure out it. I installed keepalived package and configure Unicast for it. All is working perfect. Two SDC connect to PDC and users/systems connect to Virtual IP. If one server with SDC is down - for example power outage and it's master then keepalived change to second SDC.
DNS changing is not solution for me. SDB I have too But in every office I want to have local SDC's.
If you want something like that then here I have good links:
kaivanov.blogspot.de/2015/02/kee ... k-and.html
raymii.org/s/tutorials/Keepaliv ... buntu.html
tecadmin.net/ip-failover-setup-u ... redhat-6/#
For install keepalived:
$ univention-install libssl-dev libpopt0 build-essential
$ cd /tmp
$ wget http://keepalived.org/software/keepalived-1.2.19.tar.gz
$ cd keepalived-1.2.19
$ make install
$ make clean