[RFE] Task control functions for long running tasks

[Vladyslav Drok]

This proposes unified way of controlling long running task such as
cleaning, zapping, soft reboot, soft shutdown, and inject NMI.

Control functions are:
- Abort
- Cancel/Rollback
- Get Progress (percentage, estimated end time)
- Suspend/Resume

Currently "cleaning" introduced new verb "Abort" [1], "soft reboot and
nmi" proposed new transit state CANCEL_REBOOT_SOFT,
CANCEL_POWER_OFF_SOFT and CANCEL_INJECT_NMI [2][3].

Control functions are common among tasks in concurrent programming.
It should be coordinated so that Ironic can provide customer with
unified I/F.

[1] https://review.openstack.org/#/c/201552/
[2] https://review.openstack.org/#/c/186700/
[3] https://review.openstack.org/#/c/216730/

[Vladyslav Drok (vdrok)]

Copy of whiteboard:

Gerrit topic: https://review.openstack.org/#q,topic:bp/task-control-functions-for-long-running-tasks,n,z

Addressed by: https://review.openstack.org/250783
    Add 'abort' support for Soft Power Off and Inject NMI

[Jim Rollenhagen (jim-rollenhagen)]

The patch above doesn't address a "unified way of controlling long running task". We'll need a spec written for that.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Julia Kreger (<email address hidden>) on branch: master
Review: https://review.opendev.org/250783
Reason: Abandoning spec as it has not been updated in nearly three years. If there is interest in it at a later time, it can be resurrected.