openstack
/
neutron
Code Issues Proposed changes

Fixes for missing IPs on subnets in DHCP agent 

There is a race condition server-side where a port request containing
a subnet_id is processed at the same time the subnet is being deleted,
the port operation may be successful without having a fixed IP on the
requested subnet. This patch makes the DHCP agent resillient to this
bug by checking the port response and raising a SubnetMismatchForPort
to trigger a resync if it doesn't have all of the requested subnet IDs.

Additionally, it avoids skipping assignment of IPv6 addresses to the
interface if they are stateless. The original logic to skip assignment
was only meant to be for SLAAC addresses.

Both of these issues were resulting in the KeyError observed in the
bug report.

Related-Bug: #1627480
Closes-Bug: #1624079
Change-Id: I85ef1f4d60efd0309d6a0706e29fdbcc16f0b59d
This commit is contained in:
Kevin Benton 2016-09-22 23:38:33 -07:00
parent 8de9bb4b3b
commit d1fb423830
5 changed files with 49 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
neutron/agent/dhcp/agent.py
View File

@ -120,6 +120,10 @@ class DhcpAgent(manager.Manager):
'is a conflict with its current state; please '
'check that the network and/or its subnet(s) '
'still exist.', {'net_id': network.id, 'action': action})
except exceptions.SubnetMismatchForPort as e:
# FIXME(kevinbenton): get rid of this once bug/1627480 is fixed
LOG.debug("Error configuring DHCP port, scheduling resync: %s", e)
self.schedule_resync(e, network.id)
except Exception as e:
if getattr(e, 'exc_type', '') != 'IpAddressGenerationFailure':
# Don't resync if port could not be created because of an IP

15
neutron/agent/linux/dhcp.py
View File

@ -1280,6 +1280,19 @@ class DeviceManager(object):
else:
raise exceptions.Conflict()
# FIXME(kevinbenton): ensure we have the IPs we actually need.
# can be removed once bug/1627480 is fixed
if not self.driver.use_gateway_ips:
expected = set(dhcp_subnets)
actual = {fip.subnet_id for fip in dhcp_port.fixed_ips}
missing = expected - actual
if missing:
LOG.debug("Requested DHCP port with IPs on subnets "
"%(expected)s but only got IPs on subnets "
"%(actual)s.", {'expected': expected,
'actual': actual})
raise exceptions.SubnetMismatchForPort(
port_id=dhcp_port.id, subnet_id=list(missing)[0])
# Convert subnet_id to subnet dict
fixed_ips = [dict(subnet_id=fixed_ip.subnet_id,
ip_address=fixed_ip.ip_address,
@ -1359,7 +1372,7 @@ class DeviceManager(object):
ip_cidrs = []
for fixed_ip in port.fixed_ips:
subnet = fixed_ip.subnet
if not ipv6_utils.is_auto_address_subnet(subnet):
if not ipv6_utils.is_slaac_subnet(subnet):
net = netaddr.IPNetwork(subnet.cidr)
ip_cidr = '%s/%s' % (fixed_ip.ip_address, net.prefixlen)
ip_cidrs.append(ip_cidr)

6
neutron/common/ipv6_utils.py
View File

@ -76,6 +76,12 @@ def is_auto_address_subnet(subnet):
or subnet['ipv6_ra_mode'] in modes)
def is_slaac_subnet(subnet):
"""Check if subnet is a slaac subnet."""
return (subnet['ipv6_address_mode'] == const.IPV6_SLAAC
or subnet['ipv6_ra_mode'] == const.IPV6_SLAAC)
def is_eui64_address(ip_address):
"""Check if ip address is EUI64."""
ip = netaddr.IPAddress(ip_address)

17
neutron/tests/unit/agent/dhcp/test_agent.py
View File

@ -85,6 +85,8 @@ fake_meta_subnet = dhcp.DictModel(dict(id='bbbbbbbb-1111-2222-bbbbbbbbbbbb',
fake_fixed_ip1 = dhcp.DictModel(dict(id='', subnet_id=fake_subnet1.id,
ip_address='172.9.9.9'))
fake_fixed_ip_subnet2 = dhcp.DictModel(dict(id='', subnet_id=fake_subnet2.id,
ip_address='172.9.8.9'))
fake_fixed_ip2 = dhcp.DictModel(dict(id='', subnet_id=fake_subnet1.id,
ip_address='172.9.9.10'))
fake_fixed_ipv6 = dhcp.DictModel(dict(id='', subnet_id=fake_ipv6_subnet.id,
@ -1531,13 +1533,26 @@ class TestDeviceManager(base.BaseTestCase):
[{'subnet_id': fake_fixed_ip1.subnet_id}],
'device_id': mock.ANY}})])
def test_create_dhcp_port_update_add_subnet(self):
def test_create_dhcp_port_update_add_subnet_bug_1627480(self):
# this can go away once bug/1627480 is fixed
plugin = mock.Mock()
dh = dhcp.DeviceManager(cfg.CONF, plugin)
fake_network_copy = copy.deepcopy(fake_network)
fake_network_copy.ports[0].device_id = dh.get_device_id(fake_network)
fake_network_copy.subnets[1].enable_dhcp = True
plugin.update_dhcp_port.return_value = fake_network.ports[0]
with testtools.ExpectedException(exceptions.SubnetMismatchForPort):
dh.setup_dhcp_port(fake_network_copy)
def test_create_dhcp_port_update_add_subnet(self):
plugin = mock.Mock()
dh = dhcp.DeviceManager(cfg.CONF, plugin)
fake_network_copy = copy.deepcopy(fake_network)
fake_network_copy.ports[0].device_id = dh.get_device_id(fake_network)
fake_network_copy.subnets[1].enable_dhcp = True
updated_port = copy.deepcopy(fake_network_copy.ports[0])
updated_port.fixed_ips.append(fake_fixed_ip_subnet2)
plugin.update_dhcp_port.return_value = updated_port
dh.setup_dhcp_port(fake_network_copy)
port_body = {'port': {
'network_id': fake_network.id,

16
neutron/tests/unit/agent/linux/test_dhcp.py
View File

@ -86,7 +86,9 @@ class FakeReservedPort(object):
self.device_owner = constants.DEVICE_OWNER_DHCP
self.fixed_ips = [
FakeIPAllocation('192.168.0.6',
'dddddddd-dddd-dddd-dddd-dddddddddddd')]
'dddddddd-dddd-dddd-dddd-dddddddddddd'),
FakeIPAllocation('fdca:3ba5:a17a:4ba3::2',
'ffffffff-ffff-ffff-ffff-ffffffffffff')]
self.mac_address = '00:00:80:aa:bb:ee'
self.device_id = n_const.DEVICE_ID_RESERVED_DHCP_PORT
self.extra_dhcp_opts = []
@ -2259,11 +2261,11 @@ class TestDeviceManager(TestConfBase):
plugin.update_dhcp_port.assert_called_with(reserved_port.id,
mock.ANY)
except_ips = ['192.168.0.6/24']
expect_ips = ['192.168.0.6/24', 'fdca:3ba5:a17a:4ba3::2/64']
if enable_isolated_metadata or force_metadata:
except_ips.append(dhcp.METADATA_DEFAULT_CIDR)
expect_ips.append(dhcp.METADATA_DEFAULT_CIDR)
mgr.driver.init_l3.assert_called_with('ns-XXX',
except_ips,
expect_ips,
namespace='qdhcp-ns')
def test_setup_reserved_and_disable_metadata(self):
@ -2331,9 +2333,9 @@ class TestDeviceManager(TestConfBase):
plugin.update_dhcp_port.assert_called_with(reserved_port_2.id,
mock.ANY)
mgr.driver.init_l3.assert_called_with('ns-XXX',
['192.168.0.6/24'],
namespace='qdhcp-ns')
mgr.driver.init_l3.assert_called_with(
'ns-XXX', ['192.168.0.6/24', 'fdca:3ba5:a17a:4ba3::2/64'],
namespace='qdhcp-ns')
class TestDictModel(base.BaseTestCase):