its a completely Extensive subject .
sometimes you cannot watch this through checking by nslookup.
if the domain dns zone hosted by third party like cloudflare and cloudns that will not expose the ip of nodes. then it cannot
declared with nslookup . and possibly the ip you watch in this way is only the ip of dns server not the ip of load balancing servers.
by the way using the dns records for load balancing is using same records value with different ip address . then traffic will distributed among different servers with same configuration .