Was great to see many stackers at the summit! Following-up on one of the design discussions, the consensus seemed to be that the operation which puts a host in maintenance mode should probably only disable further provisioning requests to that host, while the orchestration of migrating the individual instances from that host should be done separately, potentially even outside of Nova. One possible approach could be to use the admin API to list all the instances on a particular host, and then to migrate each of them (potentially using the option not to specify the target host, in which case the new placement will be selected by the scheduler). Similar approach may apply to recovery of instances from a failed host, using 'evacuate' API.
It would be great to understand how people might want to have this capability surfaced and consumed by the administrator. A script (somehow shared with the community)? REST API? (provided by which component?) part of nova-manage? something else? Would appreciate your feedback (especially if you manage OpenStack clouds and is interested in this capability). Thanks, Alex P.S. one additional item on our todo list is to enable usage of scheduler hints when applying the individual migration operations P.P.S. similar scenarios might be also implemented for Cinder storage nodes, ones the new volume migration feature gets implemented _______________________________________________ Mailing list: https://launchpad.net/~openstack Post to : openstack@lists.launchpad.net Unsubscribe : https://launchpad.net/~openstack More help : https://help.launchpad.net/ListHelp
