Implement a DHCP driver backed by dnsmasq

The ``[dhcp]dhcp_provider`` configuration option can now be set to
``dnsmasq`` as an alternative to ``none`` for standalone deployments.
This enables the same node-specific DHCP capabilities as the
``neutron`` provider. See the ``[dnsmasq]`` section for configuration
options.

Change-Id: I3ab86ed68c6597d4fb4b0f2ae6d4fc34b1d59f11
Story: 2010203
Task: 45922

11 files changed, 394 insertions, 10 deletions

diff --git a/ironic/common/pxe_utils.py b/ironic/common/pxe_utils.py
index 88c55d6d7..ad51bac97 100644
--- a/ironic/common/pxe_utils.py
+++ b/ironic/common/pxe_utils.py
@@ -59,6 +59,7 @@ DHCPV6_BOOTFILE_NAME = '59'  # rfc5970
 DHCP_TFTP_SERVER_ADDRESS = '150'  # rfc5859
 DHCP_IPXE_ENCAP_OPTS = '175'  # Tentatively Assigned
 DHCP_TFTP_PATH_PREFIX = '210'  # rfc5071
+DHCP_SERVER_IP_ADDRESS = '255'  # dnsmasq server-ip-address
 
 DEPLOY_KERNEL_RAMDISK_LABELS = ['deploy_kernel', 'deploy_ramdisk']
 RESCUE_KERNEL_RAMDISK_LABELS = ['rescue_kernel', 'rescue_ramdisk']
@@ -488,7 +489,7 @@ def dhcp_options_for_instance(task, ipxe_enabled=False, url_boot=False,
     else:
         use_ip_version = int(CONF.pxe.ip_version)
     dhcp_opts = []
-    dhcp_provider_name = CONF.dhcp.dhcp_provider
+    api = dhcp_factory.DHCPFactory().provider
     if use_ip_version == 4:
         boot_file_param = DHCP_BOOTFILE_NAME
     else:
@@ -517,7 +518,7 @@ def dhcp_options_for_instance(task, ipxe_enabled=False, url_boot=False,
         ipxe_script_url = '/'.join([CONF.deploy.http_url, script_name])
         # if the request comes from dumb firmware send them the iPXE
         # boot image.
-        if dhcp_provider_name == 'neutron':
+        if api.supports_ipxe_tag():
             # Neutron use dnsmasq as default DHCP agent. Neutron carries the
             # configuration to relate to the tags below. The ipxe6 tag was
             # added in the Stein cycle which identifies the iPXE User-Class
@@ -588,7 +589,7 @@ def dhcp_options_for_instance(task, ipxe_enabled=False, url_boot=False,
     # Related bug was opened on Neutron side:
     # https://bugs.launchpad.net/neutron/+bug/1723354
     if not url_boot:
-        dhcp_opts.append({'opt_name': 'server-ip-address',
+        dhcp_opts.append({'opt_name': DHCP_SERVER_IP_ADDRESS,
                           'opt_value': CONF.pxe.tftp_server})
 
     # Append the IP version for all the configuration options
diff --git a/ironic/conf/__init__.py b/ironic/conf/__init__.py
index 4e4b7bf7a..ad1ba227c 100644
--- a/ironic/conf/__init__.py
+++ b/ironic/conf/__init__.py
@@ -27,6 +27,7 @@ from ironic.conf import database
 from ironic.conf import default
 from ironic.conf import deploy
 from ironic.conf import dhcp
+from ironic.conf import dnsmasq
 from ironic.conf import drac
 from ironic.conf import glance
 from ironic.conf import healthcheck
@@ -62,6 +63,7 @@ default.register_opts(CONF)
 deploy.register_opts(CONF)
 drac.register_opts(CONF)
 dhcp.register_opts(CONF)
+dnsmasq.register_opts(CONF)
 glance.register_opts(CONF)
 healthcheck.register_opts(CONF)
 ibmc.register_opts(CONF)
diff --git a/ironic/conf/dhcp.py b/ironic/conf/dhcp.py
index 2c58529fd..17a937f7d 100644
--- a/ironic/conf/dhcp.py
+++ b/ironic/conf/dhcp.py
@@ -20,7 +20,8 @@ from ironic.common.i18n import _
 opts = [
     cfg.StrOpt('dhcp_provider',
                default='neutron',
-               help=_('DHCP provider to use. "neutron" uses Neutron, and '
+               help=_('DHCP provider to use. "neutron" uses Neutron, '
+                      '"dnsmasq" uses the Dnsmasq provider, and '
                       '"none" uses a no-op provider.')),
 ]
 
diff --git a/ironic/conf/dnsmasq.py b/ironic/conf/dnsmasq.py
new file mode 100644
index 000000000..f1ba1de23
--- /dev/null
+++ b/ironic/conf/dnsmasq.py
@@ -0,0 +1,43 @@
+#
+# Copyright 2022 Red Hat, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from oslo_config import cfg
+
+from ironic.common.i18n import _
+
+opts = [
+    cfg.StrOpt('dhcp_optsdir',
+               default='/etc/dnsmasq.d/optsdir.d',
+               help=_('Directory where the "dnsmasq" provider will write '
+                      'option configuration files for an external '
+                      'Dnsmasq to read. Use the same path for the '
+                      'dhcp-optsdir dnsmasq configuration directive.')),
+    cfg.StrOpt('dhcp_hostsdir',
+               default='/etc/dnsmasq.d/hostsdir.d',
+               help=_('Directory where the "dnsmasq" provider will write '
+                      'host configuration files for an external '
+                      'Dnsmasq to read. Use the same path for the '
+                      'dhcp-hostsdir dnsmasq configuration directive.')),
+    cfg.StrOpt('dhcp_leasefile',
+               default='/var/lib/dnsmasq/dnsmasq.leases',
+               help=_('Dnsmasq leases file for the "dnsmasq" driver to '
+                      'discover IP addresses of managed nodes. Use the'
+                      'same path for the dhcp-leasefile dnsmasq '
+                      'configuration directive.')),
+]
+
+
+def register_opts(conf):
+    conf.register_opts(opts, group='dnsmasq')
diff --git a/ironic/dhcp/base.py b/ironic/dhcp/base.py
index 57a4e7911..b2b711307 100644
--- a/ironic/dhcp/base.py
+++ b/ironic/dhcp/base.py
@@ -102,3 +102,14 @@ class BaseDHCP(object, metaclass=abc.ABCMeta):
         :raises: FailedToCleanDHCPOpts
         """
         pass
+
+    def supports_ipxe_tag(self):
+        """Whether the provider will correctly apply the 'ipxe' tag.
+
+        When iPXE makes a DHCP request, does this provider support adding
+        the tag `ipxe` or `ipxe6` (for IPv6). When the provider returns True,
+        options can be added which filter on these tags.
+
+        :returns: True when the driver supports tagging iPXE DHCP requests
+        """
+        return False
diff --git a/ironic/dhcp/dnsmasq.py b/ironic/dhcp/dnsmasq.py
new file mode 100644
index 000000000..c6f27afe4
--- /dev/null
+++ b/ironic/dhcp/dnsmasq.py
@@ -0,0 +1,159 @@
+#
+# Copyright 2022 Red Hat, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import os
+
+from oslo_log import log as logging
+from oslo_utils import uuidutils
+
+from ironic.conf import CONF
+from ironic.dhcp import base
+
+LOG = logging.getLogger(__name__)
+
+
+class DnsmasqDHCPApi(base.BaseDHCP):
+    """API for managing host specific Dnsmasq configuration."""
+
+    def update_port_dhcp_opts(self, port_id, dhcp_options, token=None,
+                              context=None):
+        pass
+
+    def update_dhcp_opts(self, task, options, vifs=None):
+        """Send or update the DHCP BOOT options for this node.
+
+        :param task: A TaskManager instance.
+        :param options: this will be a list of dicts, e.g.
+
+                        ::
+
+                         [{'opt_name': '67',
+                           'opt_value': 'pxelinux.0',
+                           'ip_version': 4},
+                          {'opt_name': '66',
+                           'opt_value': '123.123.123.456',
+                           'ip_version': 4}]
+        :param vifs: Ignored argument
+        """
+        node = task.node
+        macs = set(self._pxe_enabled_macs(task.ports))
+
+        opt_file = self._opt_file_path(node)
+        tag = node.driver_internal_info.get('dnsmasq_tag')
+        if not tag:
+            tag = uuidutils.generate_uuid()
+            node.set_driver_internal_info('dnsmasq_tag', tag)
+            node.save()
+
+        LOG.debug('Writing to %s:', opt_file)
+        with open(opt_file, 'w') as f:
+            # Apply each option by tag
+            for option in options:
+                entry = 'tag:{tag},{opt_name},{opt_value}\n'.format(
+                    tag=tag,
+                    opt_name=option.get('opt_name'),
+                    opt_value=option.get('opt_value'),
+                )
+                LOG.debug(entry)
+                f.write(entry)
+
+        for mac in macs:
+            host_file = self._host_file_path(mac)
+            LOG.debug('Writing to %s:', host_file)
+            with open(host_file, 'w') as f:
+                # Tag each address with the unique uuid scoped to
+                # this node and DHCP transaction
+                entry = '{mac},set:{tag},set:ironic\n'.format(
+                    mac=mac, tag=tag)
+                LOG.debug(entry)
+                f.write(entry)
+
+    def _opt_file_path(self, node):
+        return os.path.join(CONF.dnsmasq.dhcp_optsdir,
+                            'ironic-{}.conf'.format(node.uuid))
+
+    def _host_file_path(self, mac):
+        return os.path.join(CONF.dnsmasq.dhcp_hostsdir,
+                            'ironic-{}.conf'.format(mac))
+
+    def _pxe_enabled_macs(self, ports):
+        for port in ports:
+            if port.pxe_enabled:
+                yield port.address
+
+    def get_ip_addresses(self, task):
+        """Get IP addresses for all ports/portgroups in `task`.
+
+        :param task: a TaskManager instance.
+        :returns: List of IP addresses associated with
+                  task's ports/portgroups.
+        """
+        lease_path = CONF.dnsmasq.dhcp_leasefile
+        macs = set(self._pxe_enabled_macs(task.ports))
+        addresses = []
+        with open(lease_path, 'r') as f:
+            for line in f.readlines():
+                lease = line.split()
+                if lease[1] in macs:
+                    addresses.append(lease[2])
+        LOG.debug('Found addresses for %s: %s',
+                  task.node.uuid, ', '.join(addresses))
+        return addresses
+
+    def clean_dhcp_opts(self, task):
+        """Clean up the DHCP BOOT options for the host in `task`.
+
+        :param task: A TaskManager instance.
+
+        :raises: FailedToCleanDHCPOpts
+        """
+
+        node = task.node
+        # Discard this unique tag
+        node.del_driver_internal_info('dnsmasq_tag')
+        node.save()
+
+        # Changing the host rule to ignore will be picked up by dnsmasq
+        # without requiring a SIGHUP. When the mac address is active again
+        # this file will be replaced with one that applies a new unique tag.
+        macs = set(self._pxe_enabled_macs(task.ports))
+        for mac in macs:
+            host_file = self._host_file_path(mac)
+            with open(host_file, 'w') as f:
+                entry = '{mac},ignore\n'.format(mac=mac)
+                f.write(entry)
+
+        # Deleting the file containing dhcp-option won't remove the rules from
+        # dnsmasq but no requests will be tagged with the dnsmasq_tag uuid so
+        # these rules will not apply.
+        opt_file = self._opt_file_path(node)
+        if os.path.exists(opt_file):
+            os.remove(opt_file)
+
+    def supports_ipxe_tag(self):
+        """Whether the provider will correctly apply the 'ipxe' tag.
+
+        When iPXE makes a DHCP request, does this provider support adding
+        the tag `ipxe` or `ipxe6` (for IPv6). When the provider returns True,
+        options can be added which filter on these tags.
+
+        The `dnsmasq` provider sets this to True on the assumption that the
+        following is included in the dnsmasq.conf:
+
+        dhcp-match=set:ipxe,175
+
+        :returns: True
+        """
+        return True
diff --git a/ironic/dhcp/neutron.py b/ironic/dhcp/neutron.py
index a5cb09282..06962ad42 100644
--- a/ironic/dhcp/neutron.py
+++ b/ironic/dhcp/neutron.py
@@ -278,3 +278,14 @@ class NeutronDHCPApi(base.BaseDHCP):
             task, task.portgroups, client)
 
         return port_ip_addresses + portgroup_ip_addresses
+
+    def supports_ipxe_tag(self):
+        """Whether the provider will correctly apply the 'ipxe' tag.
+
+        When iPXE makes a DHCP request, does this provider support adding
+        the tag `ipxe` or `ipxe6` (for IPv6). When the provider returns True,
+        options can be added which filter on these tags.
+
+        :returns: True
+        """
+        return True
diff --git a/ironic/tests/unit/common/test_pxe_utils.py b/ironic/tests/unit/common/test_pxe_utils.py
index c6dc9bffa..6b1339894 100644
--- a/ironic/tests/unit/common/test_pxe_utils.py
+++ b/ironic/tests/unit/common/test_pxe_utils.py
@@ -25,6 +25,7 @@ from oslo_config import cfg
 from oslo_utils import fileutils
 from oslo_utils import uuidutils
 
+from ironic.common import dhcp_factory
 from ironic.common import exception
 from ironic.common.glance_service import image_service
 from ironic.common import pxe_utils
@@ -44,6 +45,11 @@ DRV_INFO_DICT = db_utils.get_test_pxe_driver_info()
 DRV_INTERNAL_INFO_DICT = db_utils.get_test_pxe_driver_internal_info()
 
 
+def _reset_dhcp_provider(config, provider_name):
+    config(dhcp_provider=provider_name, group='dhcp')
+    dhcp_factory.DHCPFactory._dhcp_provider = None
+
+
 # Prevent /httpboot validation on creating the node
 @mock.patch('ironic.drivers.modules.pxe.PXEBoot.__init__', lambda self: None)
 class TestPXEUtils(db_base.DbTestCase):
@@ -673,7 +679,7 @@ class TestPXEUtils(db_base.DbTestCase):
         # TODO(TheJulia): We should... like... fix the template to
         # enable mac address usage.....
         grub_tmplte = "ironic/drivers/modules/pxe_grub_config.template"
-        self.config(dhcp_provider='none', group='dhcp')
+        _reset_dhcp_provider(self.config, 'none')
         self.config(tftp_root=tempfile.mkdtemp(), group='pxe')
         link_ip_configs_mock.side_effect = \
             exception.FailedToGetIPAddressOnPort(port_id='blah')
@@ -897,7 +903,7 @@ class TestPXEUtils(db_base.DbTestCase):
                              {'opt_name': '150',
                               'opt_value': '192.0.2.1',
                               'ip_version': ip_version},
-                             {'opt_name': 'server-ip-address',
+                             {'opt_name': '255',
                               'opt_value': '192.0.2.1',
                               'ip_version': ip_version}
                              ]
@@ -1838,7 +1844,8 @@ class iPXEBuildConfigOptionsTestCase(db_base.DbTestCase):
             self.config(tftp_server='ff80::1', group='pxe')
             self.config(http_url='http://[ff80::1]:1234', group='deploy')
 
-        self.config(dhcp_provider='isc', group='dhcp')
+        _reset_dhcp_provider(self.config, 'none')
+
         if ip_version == 6:
             # NOTE(TheJulia): DHCPv6 RFCs seem to indicate that the prior
             # options are not imported, although they may be supported
@@ -1866,7 +1873,7 @@ class iPXEBuildConfigOptionsTestCase(db_base.DbTestCase):
                              {'opt_name': '67',
                               'opt_value': expected_boot_script_url,
                               'ip_version': ip_version},
-                             {'opt_name': 'server-ip-address',
+                             {'opt_name': '255',
                               'opt_value': '192.0.2.1',
                               'ip_version': ip_version}]
 
@@ -1874,7 +1881,8 @@ class iPXEBuildConfigOptionsTestCase(db_base.DbTestCase):
                               pxe_utils.dhcp_options_for_instance(
                                   task, ipxe_enabled=True))
 
-        self.config(dhcp_provider='neutron', group='dhcp')
+        _reset_dhcp_provider(self.config, 'neutron')
+
         if ip_version == 6:
             # Boot URL variable set from prior test of isc parameters.
             expected_info = [{'opt_name': 'tag:!ipxe6,59',
@@ -1897,7 +1905,7 @@ class iPXEBuildConfigOptionsTestCase(db_base.DbTestCase):
                              {'opt_name': 'tag:ipxe,67',
                               'opt_value': expected_boot_script_url,
                               'ip_version': ip_version},
-                             {'opt_name': 'server-ip-address',
+                             {'opt_name': '255',
                               'opt_value': '192.0.2.1',
                               'ip_version': ip_version}]
 
diff --git a/ironic/tests/unit/dhcp/test_dnsmasq.py b/ironic/tests/unit/dhcp/test_dnsmasq.py
new file mode 100644
index 000000000..64fe46f33
--- /dev/null
+++ b/ironic/tests/unit/dhcp/test_dnsmasq.py
@@ -0,0 +1,140 @@
+#
+# Copyright 2022 Red Hat, Inc.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import os
+import tempfile
+
+from ironic.common import dhcp_factory
+from ironic.common import utils as common_utils
+from ironic.conductor import task_manager
+from ironic.tests.unit.db import base as db_base
+from ironic.tests.unit.objects import utils as object_utils
+
+
+class TestDnsmasqDHCPApi(db_base.DbTestCase):
+
+    def setUp(self):
+        super(TestDnsmasqDHCPApi, self).setUp()
+        self.config(dhcp_provider='dnsmasq',
+                    group='dhcp')
+        self.node = object_utils.create_test_node(self.context)
+
+        self.ports = [
+            object_utils.create_test_port(
+                self.context, node_id=self.node.id, id=2,
+                uuid='1be26c0b-03f2-4d2e-ae87-c02d7f33c782',
+                address='52:54:00:cf:2d:32',
+                pxe_enabled=True)]
+
+        self.optsdir = tempfile.mkdtemp()
+        self.addCleanup(lambda: common_utils.rmtree_without_raise(
+                        self.optsdir))
+        self.config(dhcp_optsdir=self.optsdir, group='dnsmasq')
+
+        self.hostsdir = tempfile.mkdtemp()
+        self.addCleanup(lambda: common_utils.rmtree_without_raise(
+                        self.hostsdir))
+        self.config(dhcp_hostsdir=self.hostsdir, group='dnsmasq')
+
+        dhcp_factory.DHCPFactory._dhcp_provider = None
+        self.api = dhcp_factory.DHCPFactory()
+        self.opts = [
+            {
+                'ip_version': 4,
+                'opt_name': '67',
+                'opt_value': 'bootx64.efi'
+            },
+            {
+                'ip_version': 4,
+                'opt_name': '210',
+                'opt_value': '/tftpboot/'
+            },
+            {
+                'ip_version': 4,
+                'opt_name': '66',
+                'opt_value': '192.0.2.135',
+            },
+            {
+                'ip_version': 4,
+                'opt_name': '150',
+                'opt_value': '192.0.2.135'
+            },
+            {
+                'ip_version': 4,
+                'opt_name': '255',
+                'opt_value': '192.0.2.135'
+            }
+        ]
+
+    def test_update_dhcp(self):
+        with task_manager.acquire(self.context,
+                                  self.node.uuid) as task:
+            self.api.update_dhcp(task, self.opts)
+
+            dnsmasq_tag = task.node.driver_internal_info.get('dnsmasq_tag')
+            self.assertEqual(36, len(dnsmasq_tag))
+
+        hostfile = os.path.join(self.hostsdir,
+                                'ironic-52:54:00:cf:2d:32.conf')
+        with open(hostfile, 'r') as f:
+            self.assertEqual(
+                '52:54:00:cf:2d:32,set:%s,set:ironic\n' % dnsmasq_tag,
+                f.readline())
+
+        optsfile = os.path.join(self.optsdir,
+                                'ironic-%s.conf' % self.node.uuid)
+        with open(optsfile, 'r') as f:
+            self.assertEqual([
+                'tag:%s,67,bootx64.efi\n' % dnsmasq_tag,
+                'tag:%s,210,/tftpboot/\n' % dnsmasq_tag,
+                'tag:%s,66,192.0.2.135\n' % dnsmasq_tag,
+                'tag:%s,150,192.0.2.135\n' % dnsmasq_tag,
+                'tag:%s,255,192.0.2.135\n' % dnsmasq_tag],
+                f.readlines())
+
+    def test_get_ip_addresses(self):
+        with task_manager.acquire(self.context,
+                                  self.node.uuid) as task:
+            with tempfile.NamedTemporaryFile() as fp:
+                self.config(dhcp_leasefile=fp.name, group='dnsmasq')
+                fp.write(b"1659975057 52:54:00:cf:2d:32 192.0.2.198 * *\n")
+                fp.flush()
+                self.assertEqual(
+                    ['192.0.2.198'],
+                    self.api.provider.get_ip_addresses(task))
+
+    def test_clean_dhcp_opts(self):
+        with task_manager.acquire(self.context,
+                                  self.node.uuid) as task:
+            self.api.update_dhcp(task, self.opts)
+
+        hostfile = os.path.join(self.hostsdir,
+                                'ironic-52:54:00:cf:2d:32.conf')
+        optsfile = os.path.join(self.optsdir,
+                                'ironic-%s.conf' % self.node.uuid)
+        self.assertTrue(os.path.isfile(hostfile))
+        self.assertTrue(os.path.isfile(optsfile))
+
+        with task_manager.acquire(self.context,
+                                  self.node.uuid) as task:
+            self.api.clean_dhcp(task)
+
+        # assert the host file remains with the ignore directive, and the opts
+        # file is deleted
+        with open(hostfile, 'r') as f:
+            self.assertEqual(
+                '52:54:00:cf:2d:32,ignore\n',
+                f.readline())
+        self.assertFalse(os.path.isfile(optsfile))
diff --git a/releasenotes/notes/dnsmasq_dhcp-9154fcae927dc3de.yaml b/releasenotes/notes/dnsmasq_dhcp-9154fcae927dc3de.yaml
new file mode 100644
index 000000000..bbf7dad40
--- /dev/null
+++ b/releasenotes/notes/dnsmasq_dhcp-9154fcae927dc3de.yaml
@@ -0,0 +1,7 @@
+---
+features:
+  - |
+    The ``[dhcp]dhcp_provider`` configuration option can now be set to
+    ``dnsmasq`` as an alternative to ``none`` for standalone deployments. This
+    enables the same node-specific DHCP capabilities as the ``neutron`` provider.
+    See the ``[dnsmasq]`` section for configuration options.
\ No newline at end of file
diff --git a/setup.cfg b/setup.cfg
index 9b4366a84..8354ae8cc 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -52,6 +52,7 @@ wsgi_scripts =
     ironic-api-wsgi = ironic.api.wsgi:initialize_wsgi_app
 
 ironic.dhcp =
+    dnsmasq = ironic.dhcp.dnsmasq:DnsmasqDHCPApi
     neutron = ironic.dhcp.neutron:NeutronDHCPApi
     none = ironic.dhcp.none:NoneDHCPApi