With the latest release of the VSAN Beta software I decided to rebuild my VSAN nested lab. I've always used the .ova that William Lam (Blog | Twitter) created here as it's easier than having to configure the VM's individually. I've always kept the VM defaults of 4GB RAM and 2 x vCPU's but increase the disk sizes and added an additional NIC.
fdm-installer: Please refer to the log file for more details.
Not of the above resolved the issue. After raising it in the VSAN Beta forums Duncan Epping (Blog | Twitter) advised to increase the memory assigned to the nested VSAN VM's from 4GB to 6GB. In my previous nested VSAN environment I had no issues running VSAN with 4GB. After increasing all three hosts to 6GB the FDM vib installed and HA enabled successfully.