The procedure for upgrading a self-hosted Red Hat Virtualization environment, including host updates, must be documented. Assignee to work with QE to determine workflows, prerequisites, and known issues.
Assigning to Tahlia for review.
After you finish the upgrade of the engine(HE VM) you need to disable 'GlobalMaintenance' otherwise, the hosts will have the 'GlobalMaintenance' instead of 'LocalMaintenace' state and it will prevent the HE VM migration. Also I do not sure if it necessary to restart all services, "yum update" process must restart it.
Now published at https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.1-beta/html-single/self-hosted_engine_guide/#Upgrading_the_Self-Hosted_Engine