Hi. I don't know how to monitor the percentage lively, but you can see the migration status (including the total transformed and remaining memory/disk) using this command:

#nova server-migration-show SERVER_UUID VM_ID

Also, there is a scrip here http://docs.openstack.org/admin-guide/cli-nova-migrate.html (http://docs.openstack.org/admin-guide...) which can give you some ideas on vm migration monitoring.

Use 'Virsh' for that.