See the following step-by-step guide (complete w/ screenshots ) [1] that I threw together on how to use Aeolus and Snap [2] to migrate a running instance between two separate cloud providers with no downtime (demonstrated is EC2 / rackspace but this will work to/from RHEV-M or any other cloud provider supported by aeolus/deltacloud [3])

  -Mo

[1] http://mo.morsi.org/blog/node/347

[2] https://github.com/movitto/snap

[3] http://incubator.apache.org/deltacloud/drivers.html#h2