Vertical Backup Vanishes on Reboot

It appears my /opt/ folder isn’t persisting between boots. Any bright ideas how I resolve this? Or can I “install” vertical backup directly to one of my datastores?

Which ESXi version is this?

Yes, you can install vertical to any directory, including those under a datastore.

Latest ESXi 6.5.0 update 1.

Perhaps worth updating the documentation/install guide?

I installed on one of my datastores, rebooted and it has persisted, bingo!

Is there any more detail around the saving of passwords? The guide brushes on key value pairs in a json file, but I could use some more detail, a sample file perhaps?

This is a sample .verticalbackup/passwords file that provides the SFTP password:

{
"ssh_pass": "12345678"
}