Hi all, Please help to review this BP: https://blueprints.launchpad.net/nova/+spec/migration-state-field-machine I have post a BP to improve current migration state machine [1]. Please also refer to the picture of current migration state machine [2]. The current migration state machine has mixed 3 state machines for different 3 types of migration all together, which makes the whole migration framework unclear and hard to maintain. So a better solution is split it into 3 new state machines, one for each migration type. The state of each migration object is maintained by the Migration.status field. After some discussion, we cannot change the current definition of status field because it has been exposed through API. So we'd better keep the current "status" field, and add an new field "state" to class Migration, representing the migration state in the new defined state machine. And also redefine the states for each type of migration. There are also some problems in current migration type. Please refer to [3]. I think the migration framework refactor work relates to several BPs, and it is a long term work. Thanks. [1] https://blueprints.launchpad.net/nova/+spec/migration-state-machine [2] http://paste.openstack.org/show/476954/ [3] https://blueprints.launchpad.net/nova/+spec/migration-type-refactor