Open Stack

Hi folks!

This was raised several times, now I want to bring it to the wider audience. 
We're planning [1] to deprecate classic drivers in Queens and remove them in 
Rocky. It was pointed at the Forum that we'd better provide an automatic migration.

I'd like to hear your opinion on the options:

(1) Migration as part of 'ironic-dbsync upgrade'

Pros:
* nothing new to do for the operators

Cons:
* upgrade will fail completely, if for some nodes the matching hardware types 
and/or interfaces are not enabled in ironic.conf

(2) A separate script for migration

Pros:
* can be done in advance (even while still on Pike)
* a failure won't fail the whole upgrade
* will rely on drivers enabled in actually running conductors, not on ironic.conf

Cons:
* a new upgrade action before Rocky
* won't be available in packaging
* unclear how to update nodes that are in some process (e.g. cleaning), will 
probably have to be run several times

(3) Migration as part of 'ironic-dbsync online_data_migration'

Pros:
* nothing new to do for the operators, similar to (1)
* probably a more natural place to do this than (1)
* can rely on drivers enabled in actually running conductors, not on ironic.conf

Cons:
* data migration will fail, if for some nodes the matching hardware types and/or 
interfaces are not enabled in ironic.conf

(4) Do nothing, let operators handle the migration.


The most reasonable option for me seems (3), then (4). What do you think?

Dmitry

[1] 
http://specs.openstack.org/openstack/ironic-specs/specs/approved/classic-drivers-future.html