Upgrade guide: the current release's snapshot must exist in the new name and format

[vishr]

Problem

After following guides/upgrade-to-onebox-names, the first ob deploy refuses during planning:

read live secret generation: deploy planning refused: release <current> snapshot unavailable (exit 1):
cat: /var/lib/onebox/app/releases/<current>/onebox.snapshot.yml: No such file or directory

Deploy planning reads the current release's snapshot to find which workloads carry secrets. The release was written by an earlier version as ob.snapshot.yml, in the onebox.run/v1 format this version cannot read, and the guide's step 5 moves the directory but leaves the snapshot as it was.

Found migrating the goal production host. ob bootstrap passed; only the deploy stopped, with the application down.

Workaround used

Copy the project's converted v1alpha1 ob.yml into the current release as onebox.snapshot.yml, keeping ob.snapshot.yml. This is correct only when the converted file describes that release: confirm with git diff <release commit> -- ob.yml that nothing but comments differs.

Fix

Add that step to the guide after step 5, before ob bootstrap, and say that the project file must be converted to v1alpha1 before the host is moved.