ghost run seems to work, though I do get a few warnings:
[2020-04-03 18:25:08] INFO Ghost is running in production...
[2020-04-03 18:25:08] INFO Your site is now available
[2020-04-03 18:25:08] INFO Ctrl+C to shut down
[2020-04-03 18:25:08] WARN Can't connect to the bootstrap socket (localhost 8000) ECONNREFUSED
[2020-04-03 18:25:08] WARN Tries: 0
[2020-04-03 18:25:08] WARN Retrying...
[2020-04-03 18:25:08] WARN Can't connect to the bootstrap socket (localhost 8000) ECONNREFUSED
[2020-04-03 18:25:08] WARN Tries: 1
[2020-04-03 18:25:08] WARN Retrying...
[2020-04-03 18:25:08] WARN Can't connect to the bootstrap socket (localhost 8000) ECONNREFUSED
[2020-04-03 18:25:08] WARN Tries: 2
[2020-04-03 18:25:08] WARN Retrying...
[2020-04-03 18:25:08] WARN Can't connect to the bootstrap socket (localhost 8000) ECONNREFUSED
[2020-04-03 18:25:08] INFO Ghost boot 3.556s
and
ghost-mgr@lamarche:/var/www/ghost$ sudo -u ghost node -v
v12.16.1
Interestingly, the last time I reverted from a failed upgrade, Ghost 2.0 hung on start also, but then worked after a restart. I’m hesitant to not roll back when it fails to update, though, because if restarting doesn’t fix it, I’m stuck having to roll back across major versions manually.