Support ipxe with Dnsmasq

The workflow of ipxe in ironic now only support ISC dhcpd.
the cause is the option '!175,bootfile-name' is not recognized
by dnsmasq.
Add tag:!ipxe instead of !175 can correct this.

Change-Id: Ie5cb7828c68cf7536a266d1a69c4bad296f43e26
Closes-Bug: #1384577

ironic/common/pxe_utils.py

@@ -233,11 +233,19 @@ def dhcp_options_for_instance(task):
     if CONF.pxe.ipxe_enabled:
         script_name = os.path.basename(CONF.pxe.ipxe_boot_script)
         ipxe_script_url = '/'.join([CONF.pxe.http_url, script_name])
+        dhcp_provider_name = dhcp_factory.CONF.dhcp.dhcp_provider
         # if the request comes from dumb firmware send them the iPXE
-        # boot image. !175 == non-iPXE.
-        # http://ipxe.org/howto/dhcpd#ipxe-specific_options
-        dhcp_opts.append({'opt_name': '!175,bootfile-name',
-                          'opt_value': CONF.pxe.pxe_bootfile_name})
+        # boot image.
+        if dhcp_provider_name == 'neutron':
+            # Neutron use dnsmasq as default DHCP agent, add extra config
+            # to neutron "dhcp-match=set:ipxe,175" and use below option
+            dhcp_opts.append({'opt_name': 'tag:!ipxe,bootfile-name',
+                              'opt_value': CONF.pxe.pxe_bootfile_name})
+        else:
+            # !175 == non-iPXE.
+            # http://ipxe.org/howto/dhcpd#ipxe-specific_options
+            dhcp_opts.append({'opt_name': '!175,bootfile-name',
+                              'opt_value': CONF.pxe.pxe_bootfile_name})
         # If the request comes from iPXE, direct it to boot from the
         # iPXE script
         dhcp_opts.append({'opt_name': 'bootfile-name',

ironic/tests/test_pxe_utils.py

@@ -260,6 +260,7 @@ def test_dhcp_options_for_instance_ipxe(self):
         self.config(http_url='http://192.0.3.2:1234', group='pxe')
         self.config(ipxe_boot_script='/test/boot.ipxe', group='pxe')
 
+        self.config(dhcp_provider='isc', group='dhcp')
         expected_boot_script_url = 'http://192.0.3.2:1234/boot.ipxe'
         expected_info = [{'opt_name': '!175,bootfile-name',
                           'opt_value': 'fake-bootfile'},
@@ -273,6 +274,20 @@ def test_dhcp_options_for_instance_ipxe(self):
             self.assertEqual(sorted(expected_info),
                              sorted(pxe_utils.dhcp_options_for_instance(task)))
 
+        self.config(dhcp_provider='neutron', group='dhcp')
+        expected_boot_script_url = 'http://192.0.3.2:1234/boot.ipxe'
+        expected_info = [{'opt_name': 'tag:!ipxe,bootfile-name',
+                          'opt_value': 'fake-bootfile'},
+                         {'opt_name': 'server-ip-address',
+                          'opt_value': '192.0.2.1'},
+                         {'opt_name': 'tftp-server',
+                          'opt_value': '192.0.2.1'},
+                         {'opt_name': 'bootfile-name',
+                          'opt_value': expected_boot_script_url}]
+        with task_manager.acquire(self.context, self.node.uuid) as task:
+            self.assertEqual(sorted(expected_info),
+                             sorted(pxe_utils.dhcp_options_for_instance(task)))
+
     @mock.patch('ironic.common.utils.rmtree_without_raise', autospec=True)
     @mock.patch('ironic.common.utils.unlink_without_raise', autospec=True)
     @mock.patch('ironic.common.dhcp_factory.DHCPFactory.provider')