diff --git a/specs/liberty/approved/cleanup-scheduled-at.rst b/specs/liberty/approved/cleanup-scheduled-at.rst new file mode 100644 index 000000000..88c0b5f30 --- /dev/null +++ b/specs/liberty/approved/cleanup-scheduled-at.rst @@ -0,0 +1,142 @@ +.. + This work is licensed under a Creative Commons Attribution 3.0 Unported + License. + + http://creativecommons.org/licenses/by/3.0/legalcode + +===================================================== +Cleanup 'scheduled_at' column in nova instances table +===================================================== + +https://blueprints.launchpad.net/nova/+spec/cleanup-scheduled-at + +The 'scheduled_at' field is a part of the Nova instances table +Currently, the 'scheduled_at' field is no longer updated by the +Nova scheduler, instead the 'launched_at' field is used. +The 'scheduled_at' column is now redundant and should +be removed as a part of DB clean up. + +Problem description +=================== + +The 'scheduled_at' column in the nova instances table is now +redundant. This field was erstwhile used by the scheduler to denote +the time of the instance scheduling. The commit that removed it is: +https://review.openstack.org/#/c/143725/ + +Now since all of the basic VM lifecyle operations go through the +scheduler, the 'launched_at' field is sufficient for the above +mentioned scenario. + +This is a nova DB cleanup effort to get removed the 'scheduled_at' +column from the instances table and ensure backward compatibility. + +Use Cases +---------- + +This is a cleanup effort on the instances table. + + +Project Priority +----------------- + +This is a refactoring effort to make nova code cleaner. + + +Proposed change +=============== +Estimated changes are going to be in the following places: +* Remove the sqlalchemy initializations for the 'scheduled_at' field + +* Remove all unit tests, involving this field. + +* Ensure that the NovaObjects adapt to this change for handling + migration related issues. + + +Alternatives +------------ +Continue to live with dormant code in nova. + + +Data model impact +----------------- +The 'scheduled_at' column can be dropped from the Instances table since +there appears to be no code, that updates it currently. + + +REST API impact +--------------- + +None + +Security impact +--------------- + +None. + +Notifications impact +-------------------- + +None + +Other end user impact +--------------------- + +None + +Performance Impact +------------------ + +None + +Other deployer impact +--------------------- + +None + +Developer impact +---------------- + +None + + +Implementation +============== + +Assignee(s) +----------- + +Primary assignee: + +* Sudipta Biswas sbiswas7 + + +Work Items +---------- + +1. Drop the column for 'scheduled_at' from Sqlalchemy model. +2. Add migration to drop the column from the instances table. +3. Change the instances object module for migration related issues. + + +Dependencies +============ + +None + + +Testing +======= + +The changes will be exercised through the existing CI. + +Documentation Impact +==================== + +None + + +References +========== +