[ovirt-users] Upgraded host, engine now won't boot

Hello: I saw that there were updates to my ovirt-4.2 3 node hyperconverged system, so I proceeded to apply them the usual way through the UI. At one point, the hosted engine was migrated to one of the upgraded hosts, and then went "unstable" on me. Now, the hosted engine appears to be crashed: It gets powered up, but it never boots up to the point where it responds to pings or allows logins. After a while, the hosted engine shows status (via console "hosted-engine --vm-status" command) "Powering Down". It stays there for a long time. I tried forcing a poweroff then powering it on, but again, it never gets up to where it will respond to pings. --vm-status shows bad health, but up. I tried running the hosted-engine --console command, but got: [root@ovirt1 ~]# hosted-engine --console The engine VM is running on this host Connected to domain HostedEngine Escape character is ^] error: internal error: cannot find character device <null> [root@ovirt1 ~]# I tried to run the hosted-engine --upgrade-appliance command, but it hangs at obtaining certificate (understandably, as the hosted-engine is not up). How do i recover from this? And what caused this? --Jim