Soft deleting instances and the reclaim_instance_interval in Nova
I got asked the other day how the reclaim_instance_interval in Nova works, so I thought I'd write it up here in case its useful to other people.
First off, there is a periodic task run the nova-compute process (or the computer manager as a developer would know it), which runs every reclaim_instance_interval seconds. It looks for instances in the SOFT_DELETED state which don't have any tasks running at the moment for the hypervisor node that nova-compute is running on.
For each instance it finds, it checks if the instance has been soft deleted for at least reclaim_instance_interval seconds. This has the side effect from my reading of the code that an instance needs to be deleted for at least reclaim_instance_Interval seconds before it will be removed from disk, but that the instance might be up to approximately twice that age (if it was deleted just as the periodic task ran, it would skip the next run and therefore not be deleted for two intervals).
Once these conditions are met, the instance is deleted from disk.
Tags for this post: openstack nova instance delete
Related posts: Juno nova mid-cycle meetup summary: nova-network to Neutron migration; Juno Nova PTL Candidacy; Juno nova mid-cycle meetup summary: scheduler; Juno nova mid-cycle meetup summary: ironic; Review priorities as we approach juno-3; Thoughts from the PTL
Syndicated 2014-12-14 13:51:00 from stillhq.com : Mikal, a geek from Canberra living in Silicon Valley (no blather posts)