diff --git a/nova/process.py b/nova/process.py
index 8ecef158..2dc56372 100644
--- a/nova/process.py
+++ b/nova/process.py
@@ -205,12 +205,13 @@ class ProcessPool(object):
         self._pool.release()
         return rv
 
-_instance = None
-def SharedPool():
-    global _instance
-    if _instance is None:
-       _instance = ProcessPool()
-    return _instance
+class SharedPool(object):
+    _instance = None
+    def __init__(self):
+        if SharedPool._instance is None:
+            self.__class__._instance = ProcessPool()
+    def __getattr__(self, key):
+        return getattr(self._instance, key)
 
 def simple_execute(cmd, **kwargs):
     return SharedPool().simple_execute(cmd, **kwargs)
diff --git a/nova/tests/process_unittest.py b/nova/tests/process_unittest.py
index c96bb591..75187e1f 100644
--- a/nova/tests/process_unittest.py
+++ b/nova/tests/process_unittest.py
@@ -118,7 +118,7 @@ class ProcessTestCase(test.TrialTestCase):
     def test_shared_pool_is_singleton(self):
         pool1 = process.SharedPool()
         pool2 = process.SharedPool()
-        self.assert_(id(pool1) == id(pool2))
+        self.assertEqual(id(pool1._instance), id(pool2._instance))
 
     def test_shared_pool_works_as_singleton(self):
         d1 = process.simple_execute('sleep 1')