diff --git a/bin/nova-dhcpbridge b/bin/nova-dhcpbridge
index 1aaecc5b7..8ff2fac49 100755
--- a/bin/nova-dhcpbridge
+++ b/bin/nova-dhcpbridge
@@ -95,8 +95,11 @@ def init_leases(network_id):
 
 def main():
     """Parse environment and arguments and call the approproate action."""
-    argv = config.parse_args(sys.argv,
-                             default_config_files=[os.environ['FLAGFILE']])
+    try:
+        config_file = os.environ['CONFIG_FILE']
+    except KeyError:
+        config_file = os.environ['FLAGFILE']
+    argv = config.parse_args(sys.argv, default_config_files=[config_file])
     logging.setup("nova")
 
     if int(os.environ.get('TESTING', '0')):
diff --git a/nova/rootwrap/filters.py b/nova/rootwrap/filters.py
index 52808d9ec..46a812e5d 100644
--- a/nova/rootwrap/filters.py
+++ b/nova/rootwrap/filters.py
@@ -72,9 +72,11 @@ class RegExpFilter(CommandFilter):
 class DnsmasqFilter(CommandFilter):
     """Specific filter for the dnsmasq call (which includes env)"""
 
+    CONFIG_FILE_ARG = 'CONFIG_FILE'
+
     def match(self, userargs):
         if (userargs[0] == 'env' and
-            userargs[1].startswith('FLAGFILE=') and
+            userargs[1].startswith(self.CONFIG_FILE_ARG) and
             userargs[2].startswith('NETWORK_ID=') and
             userargs[3] == 'dnsmasq'):
             return True
@@ -86,11 +88,16 @@ class DnsmasqFilter(CommandFilter):
 
     def get_environment(self, userargs):
         env = os.environ.copy()
-        env['FLAGFILE'] = userargs[1].split('=')[-1]
+        env[self.CONFIG_FILE_ARG] = userargs[1].split('=')[-1]
         env['NETWORK_ID'] = userargs[2].split('=')[-1]
         return env
 
 
+class DeprecatedDnsmasqFilter(DnsmasqFilter):
+    """Variant of dnsmasq filter to support old-style FLAGFILE"""
+    CONFIG_FILE_ARG = 'FLAGFILE'
+
+
 class KillFilter(CommandFilter):
     """Specific filter for the kill calls.
        1st argument is the user to run /bin/kill under
diff --git a/nova/tests/test_nova_rootwrap.py b/nova/tests/test_nova_rootwrap.py
index 420a086eb..135a5e46e 100644
--- a/nova/tests/test_nova_rootwrap.py
+++ b/nova/tests/test_nova_rootwrap.py
@@ -54,15 +54,22 @@ class RootwrapTestCase(test.TestCase):
         filtermatch = wrapper.match_filter(self.filters, invalid)
         self.assertTrue(filtermatch is None)
 
-    def test_DnsmasqFilter(self):
-        usercmd = ['env', 'FLAGFILE=A', 'NETWORK_ID=foobar', 'dnsmasq', 'foo']
-        f = filters.DnsmasqFilter("/usr/bin/dnsmasq", "root")
+    def _test_DnsmasqFilter(self, filter_class, config_file_arg):
+        usercmd = ['env', config_file_arg + '=A', 'NETWORK_ID=foobar',
+                   'dnsmasq', 'foo']
+        f = filter_class("/usr/bin/dnsmasq", "root")
         self.assertTrue(f.match(usercmd))
         self.assertEqual(f.get_command(usercmd), ['/usr/bin/dnsmasq', 'foo'])
         env = f.get_environment(usercmd)
-        self.assertEqual(env.get('FLAGFILE'), 'A')
+        self.assertEqual(env.get(config_file_arg), 'A')
         self.assertEqual(env.get('NETWORK_ID'), 'foobar')
 
+    def test_DnsmasqFilter(self):
+        self._test_DnsmasqFilter(filters.DnsmasqFilter, 'CONFIG_FILE')
+
+    def test_DeprecatedDnsmasqFilter(self):
+        self._test_DnsmasqFilter(filters.DeprecatedDnsmasqFilter, 'FLAGFILE')
+
     def test_KillFilter(self):
         if not os.path.exists("/proc/%d" % os.getpid()):
             self.skipTest("Test requires /proc filesystem (procfs)")