When you get ‘Command returned failure code 1 during SSH session’ during adding a KVM host with the Oracle Linux Virtualization Manager, there might be something wrong with the libvertd deamon on the host you want to add.
I had this issue with adding a Oracle Linux 7.7 host.
Please check on the KVM host the following:
$ journalctl -xe
-- Unit libvirtd.service has begun starting up. Mar 26 05:30:41 hostname libvirtd[11113]: libvirt version: 5.7.0, package: 11.el7 (Unknown, 2020-03-10-13:07:09, jenkins-10-147-72-125-43ff6ce1-34af-4e5f-9321- Mar 26 05:30:41 hostname libvirtd[11113]: hostname: hostname Mar 26 05:30:41 hostname libvirtd[11113]: --listen parameter not permitted with systemd activation sockets, see 'man libvirtd' for further guidance Mar 26 05:30:41 hostname systemd[1]: libvirtd.service: main process exited, code=exited, status=6/NOTCONFIGURED Mar 26 05:30:41 hostname systemd[1]: Failed to start Virtualization daemon. -- Subject: Unit libvirtd.service has failed -- Defined-By: systemd -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel -- -- Unit libvirtd.service has failed. -- -- The result is failed.
If this is the case, you need to switch libvirtd from listening to a UNIX sockets (the systemd default), to ‘traditional mode’ normal ports. That can be done with:
$ systemctl mask libvirtd.socket libvirtd-ro.socket \
libvirtd-admin.socket libvirtd-tls.socket libvirtd-tcp.socket
$ systemctl restart libvirtd
The last command might fail if you did not install libvirtd yet.
Please also check man libvirtd for instructions.
Happy KVM-ing!