After my recent update to 7.0u2 in my Homelab. I faced two issues:
1) I got a “could not login” message when trying to access my VCSA.
2) The VCenter appliance displayed “vmdir.password is not set”

I am not 100% if they are related ( feel free to correct me in the comments or tweet me @VirtualAndrewC. I just wanted to share two articles that will help you resolve the issue if you happen to face it upon upgrading.

Article 1:Resetting root password in vCenter Server Appliance 6.5 / 6.7 / 7.x
Article 2:Error on VCSA Console after Applying Update Patch “vmdir.password is not set; aborting installation” or “Failed to Configure Network”

Good luck!