From 91d007426f109dfef2142e28741edd51dcf1fdbc Mon Sep 17 00:00:00 2001
From: Mark Washenberger <mark.washenberger@rackspace.com>
Date: Fri, 11 May 2012 09:47:10 -0400
Subject: Eliminate a race condition on instance deletes.

- Add constraint and equality conditions to nova.db[.sqlalchemy].api
- Use host constraints to ensure the compute api doesn't simply delete
  an instance from the database that a compute manager has already
  started to run.

This race condition is associated with bug #998117

Change-Id: Id74192d3e66bea073327342f57ce0f26987efd2d
---
 nova/exception.py | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'nova/exception.py')

diff --git a/nova/exception.py b/nova/exception.py
index 1e1818e7d..aff188d01 100644
--- a/nova/exception.py
+++ b/nova/exception.py
@@ -419,6 +419,11 @@ class InvalidUUID(Invalid):
     message = _("Expected a uuid but received %(uuid).")
 
 
+class ConstraintNotMet(NovaException):
+    message = _("Constraint not met.")
+    code = 412
+
+
 class NotFound(NovaException):
     message = _("Resource could not be found.")
     code = 404
-- 
cgit