soft-delete instance actions¶
https://blueprints.launchpad.net/nova/+spec/soft-delete-instance-actions
This spec is mainly a reminder of actions that have to be taken to implement the soft-delete of instance actions table when an instance is soft-deleted
Problem description¶
Currently when an instance is soft-deleted the related instance actions are not soft-deleted to allow the operator to get the history of actions taken on the instance, especially who soft-deleted the instance.
This is not an issue as such but we are inconsistent on database level because instance is marked as deleted but not the actions. We would like to improve the consitency.
Use Cases¶
As a user I still want to be able to retrieve instance actions of a soft deleted instance.
As an operator I want the instance actions to be soft-deleted when an instance is deleted.
Proposed change¶
Change how the instance action are fetched
We must change the database queries that fetch instance action to read soft deleted instance actions too.
By doing that we will be able to get instance actions of a soft-deletd instance before and after this spec is implemented.
Change on instance soft-deleting
When we soft-delete an instance we have to soft-delete all the instance actions tables (instance_actions, instance_actions_events) referencing the soft-deleted instance.
Change on instance restore
When restoring an instance we have to restore instance_actions and instance_actions_events too.
Impacts on nova-manage
nova-manage db archive_deleted_rows
There is no impact on archiving because the filter on deleted column is applyed on instances table only. Data on children tables are selected according to the selected instances. It means that in shadow tables instance actions are not soft deleted, data are basically moved from main table to shadow table.
nova-manage db purge
When using the purge command with the –before flag the filter is applied on deleted_at column for all tables except instance_actions and instance_actions_events for which the filter is applied on updated_at column.
So we have to modify the purge behavior to filter on deleted_at and updated_at columns for instance_actions and instance_actions_events tables.
Alternatives¶
The proposed changes works without changing existing data, it means that we are able to implement soft delete of instance action and make it works with the already instance actions not soft deleted without changing the API.
We could add a command to nova-manage db that will update the existing instance action that should be soft deleted. This implies an upgrade step which is much more tricky than the proposed change.
Data model impact¶
None
instance_actions and instance_actions_events are already implementing the soft-delete feature so there is no need to change schema.
REST API impact¶
None
The API will continue to return both soft-deleted and not deleted actions. As the deleted state is not returned in the api response it won’t impact the API.
Security impact¶
None
Notifications impact¶
None
Other end user impact¶
None
Performance Impact¶
None
Other deployer impact¶
None
Developer impact¶
None
Upgrade impact¶
None as long as we do not choose the alternative.
Implementation¶
Assignee(s)¶
- Primary assignee:
pslestang
- Other contributors:
N/A
Feature Liaison¶
- Feature liaison:
N/A
Work Items¶
Modify the fetch on instance_actions instance_actions_events to read deleted rows too.
soft delete instance_actions and instance_actions_events when soft deleting instances
purge with –before on instance_actions and instance_actions_events should be done on deleted_at column too.
Dependencies¶
None
Testing¶
Can be tested with unit and functional tests. We should also verify if API sample tests need to be modified since this should not have any visible api change.
Documentation Impact¶
None
References¶
Release Name |
Description |
|---|---|
Yoga |
Introduced |
