[ovirt-users] Host NonResponsive after migration to oVirt 4.4

Hi I am looking for help after my oVirt upgrade failed. I have upgraded from ovirt 4.3 to 4.4 following the instructions here: https://www.ovirt.org/documentation/upgrade_guide/#Upgrading_from_4-3 <https://www.ovirt.org/documentation/upgrade_guide/#Upgrading_from_4-3> It's a single-host (standalone engine) test environment. I wiped CentOS 7 and reinstalled a fresh CentOS 8. I installed the oVirt 4.4 repo and all the necessary software packets. I used `engine-backup --mode=restore --file=/tmp/ovirt-engine-pre-upgrade.backup --provision-all-databases` from a backup file I created before I started the upgrade. After the restore, I ran `engine-setup`. I did not get any errors during any of these steps on the console. So the upgrade could be considered successful from that perspective. After the upgrade, I login to the ovirt admin portal, and I try to "Activate" my host (was set to "Maintenance" mode before upgrade). The Activation fails with error "NonResponsive" in the GUI. Under the "bell" icon, I find the Event "Host nuc1.feric.ch is non responsive.” In /var/log/ovirt-engine/engine.log, I find the following error: ``` 2020-11-09 23:12:21,080+01 ERROR [org.ovirt.engine.core.vdsbroker.vdsbroker.GetCapabilitiesAsyncVDSCommand] (EE-ManagedScheduledExecutorService-engineScheduledThreadPool-Thread-47) [] Command 'GetCapabilitiesAsyncVDSCommand(HostName = nuc1.feric.ch, VdsIdAndVdsVDSCommandParametersBase:{hostId='d7c30cc0-ac59-4cf3-a1e7-b9fae9db83fb', vds=‘Host[nuc1.feric.h,d7c30cc0-ac59-4cf3-a1e7-b9fae9db83fb]'})' execution failed: java.net.ConnectException: Connection refused ``` `systemctl status ovirt-engine` shows that the engine is running. I am able to reboot the host from the oVirt GUI directly. Does anyone have an idea how to proceed? Many thanks Toni