OK, I am testing in the lab a vsan cluster for 6.0.
I have my esx hosts running 6.0.0 and vcenter server is 6.0.0 also.
I have platform services on one vm and vcenter on another. I was able to create a datacenter and then a cluster underneath.
Next I went to try and add a host to my cluster and I get this error....
Cannot contact the specified host (hostname\IP). The host may not be available on the network, a network configuration problem may exist, or the management services on this host may not be responding.
Per this KB: VMware KB: Adding a VMware ESXi/ESX host to VMware vCenter Server fails
I confirmed that my vcenter server and platform services server can see all the esx hosts. From within the vcenter server, it can ping the esx hosts and putty can get to all of them. I even installed the thick client and it can connect to all the esx hosts. I used netbios name, FQDN and IP and they all worked.
I only have one subnet so that's not an issue. DNS resolution works across the board from both directions, from vcenter to esx hosts and esx hosts to vcenter.
I'm quite stumped. 