Live migration of VMs take multiple hours to complete

Issue

• VMs running memory intensive workloads, such as RHOCP worker nodes, take multiple hours to complete live migration
• During live migration, openstack server show -c progress <server id> remains with the same value for hours. even though memory is still being copied from source to target node
• During a live migration window, nova-compute reports errors connecting to RabbitMQ
• Certain operations, such as adding or removing volumes, on VMs that are in process of being live migrated, fail to complete, or complete only partially