Merge "DB Hygiene user story"

user-stories/draft/db-hygiene.rst

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+Database cleanup of deleted object
+============================================
+
+*Problem description*
+---------------------
+Each operator of an OpenStack cloud needs the ability to clean up the OpenStack
+database of objects which have been deleted. Currently a new record is created in
+the OpenStack database when an object (project, user, VM, network, volume, swift
+object, etc.) is created. When an object is deleted its record in the database
+remains but is marked as deleted.  As an OpenStack cloud stays in operation over
+time, the number of records in the database fills with deleted object records and
+soon the database becomes too large. This can result in the database consuming
+significant resources on the controller node(s) and impacting responsiveness of
+the database, even bringing down controller(s).
+
+While a record for deletion of an object is needed for cloud governance it is
+not a requirement for the database to retain this record. Thus, some tool is
+needed for OpenStack operators to cleanup the database of records from deleted
+objects.
+
+* As part of a PoC of an OpenStack cloud, an operator needs a tool to purge the
+database of deleted records. This is needed in order to be able to rerun the same
+test tool that would create objects every run as well as testing actual growth of
+the database for operational conditions not OpenStack implementation artifacts.
+
+* As an operator of an OpenStack cloud I need an ability to remove records of
+deleted objects from the database after storing those records for audit purposes.
+
+* As a cloud deployment engineer, I need to be able to re-run the same tests
+(with same objects) in a repeatable manner so that I can have a high certainty
+in the outcome of my proof of concept and cloud functionality.
+
+* As a cloud deployment engineer, I need only the appropriate records in my
+database so that I can complete my upgrade in the allocated down time.
+
+Usage Scenarios Examples
+------------------------
+TBD
+
+Opportunity/Justification
+-------------------------
+DB hygiene is required for handling OpenStack performance, operational and
+upgrade issues. This ensures that historical records of deleted items are not
+impacting operational performance and such deleted items are not polluted by
+upgrades.
+
+
+Related User Stories
+--------------------
+Nova specs:
+* https://review.openstack.org/#/c/184645/
+* https://review.openstack.org/#/c/184637/
+* https://review.openstack.org/#/c/137669/
+
+Cinder blueprint:
+* https://blueprints.launchpad.net/cinder/+spec/db-cleanup
+
+*Requirements*
+--------------
+* Operator should be able to specify which policy to apply for deleted objects
+* Operator should be able to specify which policy to apply for different tenants
+and sub-tenants.
+* At least two policies must be supported: Policy 1 - Archive the records in
+other persistent storage for a specific interval duration; Policy 2 - Remove
+the records from database permanently.
+
+*Gaps*
+------
+None currently known.
+
+*Affected By*
+-------------
+None.
+
+*External References*
+---------------------
+None.
+
+Glossary
+--------
+None.