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[Thierry Carrez <thierry.carrez+lp@xxxxxxxxx>]

** Also affects: nova/kilo
   Importance: Undecided
       Status: New

** Changed in: nova/kilo
    Milestone: None => kilo-rc2

** Changed in: nova/kilo
       Status: New => In Progress

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https://bugs.launchpad.net/bugs/1444630

Title:
  nova-compute should stop handling virt lifecycle events when it's
  shutting down

Status in OpenStack Compute (Nova):
  Fix Committed
Status in OpenStack Compute (nova) kilo series:
  In Progress

Bug description:
  This is a follow on to bug 1293480 and related to bug 1408176 and bug
  1443186.

  There can be a race when rebooting a compute host where libvirt is
  shutting down guest VMs and sending STOPPED lifecycle events up to
  nova compute which then tries to stop them via the stop API, which
  sometimes works and sometimes doesn't - the compute service can go
  down with a vm_state of ACTIVE and task_state of powering-off which
  isn't resolve on host reboot.

  Sometimes the stop API completes and the instance is stopped with
  power_state=4 (shutdown) in the nova database.  When the host comes
  back up and libvirt restarts, it starts up the guest VMs which sends
  the STARTED lifecycle event and nova handles that but because the
  vm_state in the nova database is STOPPED and the power_state is 1
  (running) from the hypervisor, nova things it started up unexpectedly
  and stops it:

  http://git.openstack.org/cgit/openstack/nova/tree/nova/compute/manager.py?id=2015.1.0rc1#n6145

  So nova shuts the running guest down.

  Actually the block in:

  http://git.openstack.org/cgit/openstack/nova/tree/nova/compute/manager.py?id=2015.1.0rc1#n6145

  conflicts with the statement in power_state.py:

  http://git.openstack.org/cgit/openstack/nova/tree/nova/compute/power_state.py?id=2015.1.0rc1#n19

  "The hypervisor is always considered the authority on the status
  of a particular VM, and the power_state in the DB should be viewed as a
  snapshot of the VMs's state in the (recent) past."

  Anyway, that's a different issue but the point is when nova-compute is
  shutting down it should stop accepting lifecycle events from the
  hypervisor (virt driver code) since it can't really reliably act on
  them anyway - we can leave any sync up that needs to happen in
  init_host() in the compute manager.

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