如果受影响的虚拟机也挂载有卷，那么先要生成一个实例和卷的UUID的列表：
select nova.instances.uuid as instance_uuid, cinder.volumes.id as volumes_uuid, cinder.volumes.status, cinder.volumes.attach_status, cinder.volumes.mountpoint, cinder.volumes.display_name from cinder.volumes inner join nova.instances on cinder.volumes.instance_uuid=nova.instances.uuid where nova.instances.host = 'compute24';
高版本有一个表专门连接实例uuid和卷uuid对应的：
nova volume-detach instance_uuid volume_uuid
nova volume-attach instance_uuid volume_uuid /dev/vdX
update instances set host = 'compute5' where host = 'compute6' and deleted = 0;
nova reboot --hard instance_uuid
nova host-evacuate --on-shared-storage compute24
nova service-disable compute24 nova-compute