Open Stack

I've posted a spec [1] for nova's integration with searchlight for 
listing instance across multiple cells. One of the open questions I have 
on that is when/how do instances get removed from searchlight?

When an instance gets deleted via the compute API today, it's not really 
deleted from the database. It's considered "soft" deleted and you can 
still list (soft) deleted instances from the database via the compute 
API if you're an admin.

Nova will be sending instance.destroy notifications to searchlight but 
we don't really want the ES entry removed because we still have to 
support the compute API contract to list deleted instances. Granted, 
this is a pretty limp contract because there is no guarantee that you'll 
be able to list those deleted instances forever because once they get 
archived (moved to shadow tables in the nova database) or purged (hard 
delete), then they are gone from that API query path.

So I'm wondering at what point instances stored in searchlight will be 
removed. Maybe there is already an answer to this and the searchlight 
team can just inform me. Otherwise we might need to think about data 
retention policies and how long a deleted instances will be stored in 
searchlight before it's removed. Again, I'm not sure if nova would 
control this or if it's something searchlight supports already.

[1] https://review.openstack.org/#/c/441692/

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Thanks,

Matt Riedemann