[Users] two node ovirt cluster with HA

Hi all , I was setting a two node ovirt cluster with ovirt engine on seperate node . I completed the configuration and tested VM live migrations with out any issues . Then for checking cluster HA I powered down one host and expected vms running on that host to be migrated to the other one . But nothing happened , Engine detected host as un-rechable and marked it as non-operational and vm ran on that host went to 'unknown state' . Is that not possible to setup a fully HA ovirt cluster with two nodes ? or else is that my configuration problem ? please advice . Thanks & Regards Alex