Ok,
After successful updates on SSO Service Endpoints on Node1 (SSOA)
I put back Node2 (SSOB) online..
Run SSOlscli listServices https://ssob.domain.com:7444/lookupservice/sdk
Return Code is : OperationFailed.
100
Looking at LB logs, came to know the traffic is going to SSOB.
Changed the Mapping rule for /sso-adminserver to use a specific Pool which contain only 1 node i.e., SSOA.
(dont know if this is the right way)
Now the traffic moved to SSOA.
Now let me try Installing Inventory Service on a server which already have vCenter 5.0 installed.. so it will be kind of upgrade from 5.0 to 5.1.