This was a mind twisting problem! I upgraded our Horizon View infrastructure to version 7 on our ESXi 6 U1 hosts. After that I was able to compose new VDIs but their DNS names on admin console had always the name of the master image! An unreachable agent error terminated the procedure.
I tried almost everything. I checked registry keys, reinstalled the horizon agent and the VMware tools, but the DNS name on the admin console still had the name of the master image. On our active directory everything was fine, the DNS names were right and DHCP was working normally. I checked the connectivity between the new VDIs and the connection servers and everything was exellent! The listening ports on connection servers were open wide and there was no firewall in between. I even reinstalled the composer servers and the connection servers.
I started freaking out, so I returned back to basics. I thought, that the composing phase was working fine, just the VDIs could not pass the DNS information to the connection servers. I started to think that the horizon agent or the VMware tools was the problem. The agent was the latest version, what about the tools? Then I came across the release notes of Horizon View 7, stating in red color
“Importantly note about installing VMware Tools
If you plan to install a version of VMware Tools downloaded from VMware Product Downloads, rather than the default version provided with vSphere, make sure that the VMware Tools version is supported. To determine which VMware Tools versions are supported, go to the VMware Product Interoperability Matrix, select the solution VMware Horizon View and the version, then select VMware Tools (downloadable only).”
So I went to VMware’s PIM page and I found this…
Finally, installing the latest 10.0.8 version solved the problem!