I think the DocImpact in the nova change was probably just to get the config options docs updated with the new workaround option.
If there is anything else we could do with this, it could be to note in the docs related to evacuate operations that if you're running nova < liberty, there is a potential data loss issue with the evacuate functionality if you don't have that patch and don't set the option appropriately. For example: http://docs.openstack.org/user-guide-admin/cli_nova_evacuate.html http://docs.openstack.org/admin-guide-cloud/compute-node-down.html There was a spec in liberty to make this smarter, but the existing problem description applies to nova compute nodes < liberty: http://specs.openstack.org/openstack/nova- specs/specs/liberty/implemented/robustify_evacuate.html#problem- description If the hostname changes on the compute or you have a typo in your configs (multiple compute nodes managing the same vcenter running at the same time), that evacuate code can delete your instances. That's why the workarounds.destroy_after_evacuate=False option is a way to safely get around this until you're sure that you're cleaning up a failed compute node (a real evacuation rather than a misconfiguration or hostname change), until you get your computes to liberty+. ** Changed in: nova Status: New => Invalid -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1461459 Title: Allow disabling the evacuate cleanup mechanism in compute manager Status in OpenStack Compute (nova): Invalid Status in openstack-manuals: Triaged Bug description: https://review.openstack.org/174779 commit 6f1f9dbc211356a3d0e2d46d3a984d7ceee79ca6 Author: Tony Breeds <t...@bakeyournoodle.com> Date: Tue Jan 27 11:17:54 2015 -0800 Allow disabling the evacuate cleanup mechanism in compute manager This mechanism attempts to destroy any locally-running instances on startup if instance.host != self.host. The assumption is that the instance has been evacuated and is safely running elsewhere. This is a dangerous assumption to make, so this patch adds a configuration variable to disable this behavior if it's not desired. Note that disabling it may have implications for the case where instances *were* evacuated, given potential shared resources. To counter that problem, this patch also makes _init_instance() skip initialization of the instance if it appears to be owned by another host, logging a prominent warning in that case. As a result, if you have destroy_after_evacuate=False and you start a nova compute with an incorrect hostname, or run it twice from another host, then the worst that will happen is you get log warnings about the instances on the host being ignored. This should be an indication that something is wrong, but still allow for fixing it without any loss. If the configuration option is disabled and a legitimate evacuation does occur, simply enabling it and then restarting the compute service will cause the cleanup to occur. This is added to the workarounds config group because it is really only relevant while evacuate is fundamentally broken in this way. It needs to be refactored to be more robust, and once that is done, this should be able to go away. Conflicts: nova/compute/manager.py nova/tests/unit/compute/test_compute.py nova/tests/unit/compute/test_compute_mgr.py nova/utils.py NOTE: In nova/utils.py a new section has been introduced but only the option addessed by this backport has been included. DocImpact: New configuration option, and peril warning Partial-Bug: #1419785 (cherry picked from commit 922148ac45c5a70da8969815b4f47e3c758d6974) -- squashed with commit -- Create a 'workarounds' config group. This group is for very specific reasons. If you're: - Working around an issue in a system tool (e.g. libvirt or qemu) where the fix is in flight/discussed in that community. - The tool can be/is fixed in some distributions and rather than patch the code those distributions can trivially set a config option to get the "correct" behavior. This is a good place for your workaround. (cherry picked from commit b1689b58409ab97ef64b8cec2ba3773aacca7ac5) -- Change-Id: Ib9a3c72c096822dd5c65c905117ae14994c73e99 To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1461459/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : yahoo-eng-team@lists.launchpad.net Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp