You should manually configure NLB and ARR outside of SnapCenter installation for high availability (HA) from SnapCenter 4.2 .
How to configure NLB and ARR with SnapCenter has information about how to configure Network Load Balancing (NLB) and Application Request Routing (ARR) with SnapCenter.
NetApp Knowledgebase Answer 1087382: How to configure NLB and ARR with SnapCenter