Kill processes when cleaning up namespaces

This patch will kill processes that are listening on any port/UNIX
socket within the namespace to be cleaned up. To kill them it will
issue a SIGTERM to them (or to their parents if they were forked) and,
if they don't die after a few seconds, a SIGKILL to them and all their
children.

This is intended for those cases when there's no specific cleanup and
serves as a fallback method.

Change-Id: I4195f633ef4a1788496d1293846f19eef89416aa
Partial-Bug: #1403455
(cherry picked from commit 1d38f30555)

etc/neutron/rootwrap.d/dhcp.filters

@@ -13,8 +13,8 @@ dnsmasq: CommandFilter, dnsmasq, root
 # dhcp-agent uses kill as well, that's handled by the generic KillFilter
 # it looks like these are the only signals needed, per
 # neutron/agent/linux/dhcp.py
-kill_dnsmasq: KillFilter, root, /sbin/dnsmasq, -9, -HUP
-kill_dnsmasq_usr: KillFilter, root, /usr/sbin/dnsmasq, -9, -HUP
+kill_dnsmasq: KillFilter, root, /sbin/dnsmasq, -9, -HUP, -15
+kill_dnsmasq_usr: KillFilter, root, /usr/sbin/dnsmasq, -9, -HUP, -15
 
 ovs-vsctl: CommandFilter, ovs-vsctl, root
 ivs-ctl: CommandFilter, ivs-ctl, root

etc/neutron/rootwrap.d/l3.filters

@@ -19,10 +19,10 @@ radvd: CommandFilter, radvd, root
 # metadata proxy
 metadata_proxy: CommandFilter, neutron-ns-metadata-proxy, root
 # RHEL invocation of the metadata proxy will report /usr/bin/python
-kill_metadata: KillFilter, root, python, -9
-kill_metadata7: KillFilter, root, python2.7, -9
-kill_radvd_usr: KillFilter, root, /usr/sbin/radvd, -9, -HUP
-kill_radvd: KillFilter, root, /sbin/radvd, -9, -HUP
+kill_metadata: KillFilter, root, python, -15, -9
+kill_metadata7: KillFilter, root, python2.7, -15, -9
+kill_radvd_usr: KillFilter, root, /usr/sbin/radvd, -15, -9, -HUP
+kill_radvd: KillFilter, root, /sbin/radvd, -15, -9, -HUP
 
 # ip_lib
 ip: IpFilter, ip, root

etc/neutron/rootwrap.d/netns-cleanup.filters

@@ -0,0 +1,12 @@
+# neutron-rootwrap command filters for nodes on which neutron is
+# expected to control network
+#
+# This file should be owned by (and only-writeable by) the root user
+
+# format seems to be
+# cmd-name: filter-name, raw-command, user, args
+
+[Filters]
+
+# netns-cleanup
+netstat: CommandFilter, netstat, root

neutron/agent/linux/async_process.py

@@ -174,15 +174,11 @@ class AsyncProcess(object):
         try:
             # A process started by a root helper will be running as
             # root and need to be killed via the same helper.
-            utils.execute(['kill', '-%d' % kill_signal, pid],
-                          run_as_root=self.run_as_root)
-        except Exception as ex:
-            stale_pid = (isinstance(ex, RuntimeError) and
-                         'No such process' in str(ex))
-            if not stale_pid:
-                LOG.exception(_LE('An error occurred while killing [%s].'),
-                              self.cmd)
-                return False
+            utils.kill_process(pid, kill_signal, self.run_as_root)
+        except Exception:
+            LOG.exception(_LE('An error occurred while killing [%s].'),
+                          self.cmd)
+            return False
 
         if self._process:
             self._process.wait()

neutron/agent/linux/utils.py

@@ -165,9 +165,11 @@ def get_interface_mac(interface):
                     for char in info[MAC_START:MAC_END]])[:-1]
 
 
-def find_child_pids(pid):
-    """Retrieve a list of the pids of child processes of the given pid."""
+def find_child_pids(pid, recursive=False):
+    """Retrieve a list of the pids of child processes of the given pid.
 
+    It can also find all children through the hierarchy if recursive=True
+    """
     try:
         raw_pids = execute(['ps', '--ppid', pid, '-o', 'pid='],
                            log_fail_as_error=False)
@@ -179,7 +181,58 @@ def find_child_pids(pid):
             if no_children_found:
                 ctxt.reraise = False
                 return []
-    return [x.strip() for x in raw_pids.split('\n') if x.strip()]
+    child_pids = [x.strip() for x in raw_pids.split('\n') if x.strip()]
+    if recursive:
+        for child in child_pids:
+            child_pids = child_pids + find_child_pids(child, True)
+    return child_pids
+
+
+def find_parent_pid(pid):
+    """Retrieve the pid of the parent process of the given pid.
+
+    If the pid doesn't exist in the system, this function will return
+    None
+    """
+    try:
+        ppid = execute(['ps', '-o', 'ppid=', pid],
+                       log_fail_as_error=False)
+    except ProcessExecutionError as e:
+        # Unexpected errors are the responsibility of the caller
+        with excutils.save_and_reraise_exception() as ctxt:
+            # Exception has already been logged by execute
+            no_such_pid = e.returncode == 1
+            if no_such_pid:
+                ctxt.reraise = False
+                return
+    return ppid.strip()
+
+
+def find_fork_top_parent(pid):
+    """Retrieve the pid of the top parent of the given pid through a fork.
+
+    This function will search the top parent with its same cmdline. If the
+    given pid has no parent, its own pid will be returned
+    """
+    while True:
+        ppid = find_parent_pid(pid)
+        if (ppid and ppid != pid and
+                pid_invoked_with_cmdline(ppid, get_cmdline_from_pid(pid))):
+            pid = ppid
+        else:
+            return pid
+
+
+def kill_process(pid, signal, run_as_root=False):
+    """Kill the process with the given pid using the given signal."""
+    try:
+        execute(['kill', '-%d' % signal, pid], run_as_root=run_as_root)
+    except ProcessExecutionError as ex:
+        # TODO(dalvarez): this check has i18n issues. Maybe we can use
+        # use gettext module setting a global locale or just pay attention
+        # to returncode instead of checking the ex message.
+        if 'No such process' not in str(ex):
+            raise
 
 
 def _get_conf_base(cfg_root, uuid, ensure_conf_dir):

neutron/cmd/netns_cleanup.py

@@ -15,6 +15,7 @@
 
 import itertools
 import re
+import signal
 import time
 
 from neutron_lib import constants
@@ -22,7 +23,7 @@ from oslo_config import cfg
 from oslo_log import log as logging
 from oslo_utils import importutils
 
-from neutron._i18n import _LE
+from neutron._i18n import _LE, _LW
 from neutron.agent.common import config as agent_config
 from neutron.agent.common import ovs_lib
 from neutron.agent.l3 import agent as l3_agent
@@ -32,7 +33,9 @@ from neutron.agent.linux import dhcp
 from neutron.agent.linux import external_process
 from neutron.agent.linux import interface
 from neutron.agent.linux import ip_lib
+from neutron.agent.linux import utils
 from neutron.common import config
+from neutron.common import utils as common_utils
 from neutron.conf.agent import cmd
 from neutron.conf.agent import dhcp as dhcp_config
 
@@ -44,6 +47,12 @@ NS_PREFIXES = {
     'l3': [l3_agent.NS_PREFIX, dvr.SNAT_NS_PREFIX, dvr_fip_ns.FIP_NS_PREFIX],
     'lbaas': [LB_NS_PREFIX],
 }
+SIGTERM_WAITTIME = 10
+NETSTAT_PIDS_REGEX = re.compile(r'.* (?P<pid>\d{2,6})/.*')
+
+
+class PidsInNamespaceException(Exception):
+    pass
 
 
 class FakeDhcpPlugin(object):
@@ -130,6 +139,87 @@ def unplug_device(conf, device):
         device.set_log_fail_as_error(orig_log_fail_as_error)
 
 
+def find_listen_pids_namespace(namespace):
+    """Retrieve a list of pids of listening processes within the given netns.
+
+    It executes netstat -nlp and returns a set of unique pairs
+    """
+    ip = ip_lib.IPWrapper(namespace=namespace)
+    pids = set()
+    cmd = ['netstat', '-nlp']
+    output = ip.netns.execute(cmd, run_as_root=True)
+    for line in output.splitlines():
+        m = NETSTAT_PIDS_REGEX.match(line)
+        if m:
+            pids.add(m.group('pid'))
+    return pids
+
+
+def wait_until_no_listen_pids_namespace(namespace, timeout=SIGTERM_WAITTIME):
+    """Poll listening processes within the given namespace.
+
+    If after timeout seconds, there are remaining processes in the namespace,
+    then a PidsInNamespaceException will be thrown.
+    """
+    # Would be better to handle an eventlet.timeout.Timeout exception
+    # but currently there's a problem importing eventlet since it's
+    # doing a local import from cmd/eventlet which doesn't have a
+    # timeout module
+    common_utils.wait_until_true(
+        lambda: not find_listen_pids_namespace(namespace),
+        timeout=SIGTERM_WAITTIME,
+        exception=PidsInNamespaceException)
+
+
+def _kill_listen_processes(namespace, force=False):
+    """Identify all listening processes within the given namespace.
+
+    Then, for each one, find its top parent with same cmdline (in case this
+    process forked) and issue a SIGTERM to all of them. If force is True,
+    then a SIGKILL will be issued to all parents and all their children. Also,
+    this function returns the number of listening processes.
+    """
+    pids = find_listen_pids_namespace(namespace)
+    pids_to_kill = {utils.find_fork_top_parent(pid) for pid in pids}
+    kill_signal = signal.SIGTERM
+    if force:
+        kill_signal = signal.SIGKILL
+        children = [utils.find_child_pids(pid, True) for pid in pids_to_kill]
+        pids_to_kill.update(itertools.chain.from_iterable(children))
+
+    for pid in pids_to_kill:
+        # Throw a warning since this particular cleanup may need a specific
+        # implementation in the right module. Ideally, netns_cleanup wouldn't
+        # kill any processes as the responsible module should've killed them
+        # before cleaning up the namespace
+        LOG.warning(_LW("Killing (%(signal)d) [%(pid)s] %(cmdline)s"),
+                    {'signal': kill_signal,
+                     'pid': pid,
+                     'cmdline': ' '.join(utils.get_cmdline_from_pid(pid))[:80]
+                     })
+        try:
+            utils.kill_process(pid, kill_signal, run_as_root=True)
+        except Exception as ex:
+            LOG.error(_LE('An error occurred while killing '
+                          '[%(pid)s]: %(msg)s'), {'pid': pid, 'msg': ex})
+    return len(pids)
+
+
+def kill_listen_processes(namespace):
+    """Kill all processes listening within the given namespace.
+
+    First it tries to kill them using SIGTERM, waits until they die gracefully
+    and then kills remaining processes (if any) with SIGKILL
+    """
+    if _kill_listen_processes(namespace, force=False):
+        try:
+            wait_until_no_listen_pids_namespace(namespace)
+        except PidsInNamespaceException:
+            _kill_listen_processes(namespace, force=True)
+            # Allow some time for remaining processes to die
+            wait_until_no_listen_pids_namespace(namespace)
+
+
 def destroy_namespace(conf, namespace, force=False):
     """Destroy a given namespace.
 
@@ -145,6 +235,14 @@ def destroy_namespace(conf, namespace, force=False):
             # NOTE: The dhcp driver will remove the namespace if is it empty,
             # so a second check is required here.
             if ip.netns.exists(namespace):
+                try:
+                    kill_listen_processes(namespace)
+                except PidsInNamespaceException:
+                    # This is unlikely since, at this point, we have SIGKILLed
+                    # all remaining processes but if there are still some, log
+                    # the error and continue with the cleanup
+                    LOG.error(_LE('Not all processes were killed in %s'),
+                              namespace)
                 for device in ip.get_devices(exclude_loopback=True):
                     unplug_device(conf, device)
 

neutron/tests/contrib/functional-testing.filters

@@ -41,3 +41,9 @@ ovstrace_filter: RegExpFilter, ovs-appctl, root, ovs-appctl, ofproto/trace, .*,
 # needed for TestGetRootHelperChildPid
 bash_filter: RegExpFilter, /bin/bash, root, bash, -c, \(sleep 100\)
 sleep_kill: KillFilter, root, sleep, -9
+
+#needed by test_netns_cleanup
+process_spawn: EnvFilter, env, root, PATH=, python
+ip_exec: IpNetnsExecFilter, ip, root
+ps: CommandFilter, ps, root
+pid_kill: RegExpFilter, kill, root, kill, -\d+, .*

neutron/tests/functional/cmd/process_spawn.py

@@ -0,0 +1,180 @@
+# Copyright 2016 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 signal
+import socket
+import sys
+import time
+
+from neutron_lib import constants as n_const
+from oslo_config import cfg
+
+from neutron._i18n import _
+from neutron.agent.linux import daemon
+from neutron.tests.common import net_helpers
+
+UNIX_FAMILY = 'UNIX'
+
+OPTS = [
+    cfg.IntOpt('num_children',
+               short='n',
+               default=0,
+               help=_('Number of children to spawn'),
+               required=False),
+    cfg.StrOpt('family',
+               short='f',
+               default=n_const.IPv4,
+               choices=[n_const.IPv4, n_const.IPv6, UNIX_FAMILY],
+               help=_('Listen socket family (%(v4)s, %(v6)s or %(unix)s)') %
+                     {
+                         'v4': n_const.IPv4,
+                         'v6': n_const.IPv6,
+                         'unix': UNIX_FAMILY
+                     },
+               required=False),
+    cfg.StrOpt('proto',
+               short='p',
+               default=n_const.PROTO_NAME_TCP,
+               choices=[n_const.PROTO_NAME_TCP, n_const.PROTO_NAME_UDP],
+               help=_('Protocol (%(tcp)s or %(udp)s)') %
+                     {
+                         'tcp': n_const.PROTO_NAME_TCP,
+                         'udp': n_const.PROTO_NAME_UDP
+                     },
+               required=False),
+    cfg.BoolOpt('parent_listen',
+               short='pl',
+               default=True,
+               help=_('Parent process must listen too'),
+               required=False),
+    cfg.BoolOpt('ignore_sigterm',
+                short='i',
+                default=False,
+                help=_('Ignore SIGTERM'),
+                required=False)
+]
+
+
+class ProcessSpawn(daemon.Daemon):
+    """
+    This class is part of the functional test of the netns_cleanup module.
+
+    It allows spawning processes that listen on random ports either on
+    tcp(6), udp(6) or unix sockets. Also it allows handling or ignoring
+    SIGTERM to check whether the cleanup works as expected by getting rid
+    of the spawned processes.
+    """
+
+    MAX_BIND_RETRIES = 5
+
+    DCT_FAMILY = {
+        n_const.IPv4: socket.AF_INET,
+        n_const.IPv6: socket.AF_INET6,
+        UNIX_FAMILY: socket.AF_UNIX
+    }
+    DCT_PROTO = {
+        n_const.PROTO_NAME_TCP: socket.SOCK_STREAM,
+        n_const.PROTO_NAME_UDP: socket.SOCK_DGRAM,
+    }
+
+    def __init__(self, pidfile=None,
+                 family=n_const.IPv4,
+                 proto=n_const.PROTO_NAME_TCP,
+                 ignore_sigterm=False, num_children=0,
+                 parent_must_listen=True):
+        self.family = family
+        self.proto = proto
+        self.ignore_sigterm = ignore_sigterm
+        self.num_children = num_children
+        self.listen_socket = None
+        self.parent_must_listen = parent_must_listen
+        self.child_pids = []
+
+        super(ProcessSpawn, self).__init__(pidfile)
+
+    def start_listening(self):
+        socket_family = self.DCT_FAMILY[self.family]
+        socket_type = self.DCT_PROTO[self.proto]
+
+        self.listen_socket = socket.socket(socket_family, socket_type)
+
+        # Try to listen in a random port which is not currently in use
+        retries = 0
+        while retries < ProcessSpawn.MAX_BIND_RETRIES:
+            # NOTE(dalvarez): not finding a free port on a freshly created
+            # namespace is very unlikely but if problems show up, retries can
+            # be increased to avoid tests failing
+            try:
+                if self.family == UNIX_FAMILY:
+                    self.listen_socket.bind('')
+                else:
+                    port = net_helpers.get_free_namespace_port(self.proto)
+                    self.listen_socket.bind(('', port))
+            except socket.error:
+                retries += 1
+            else:
+                if n_const.PROTO_NAME_TCP in self.proto:
+                    self.listen_socket.listen(0)
+                break
+
+    def do_sleep(self):
+        while True:
+            time.sleep(10)
+
+    def run(self):
+        # Spawn as many children as requested
+        children = []
+        while len(children) != self.num_children:
+            child_pid = os.fork()
+            if child_pid == 0:
+                # Listen and do nothing else
+                self.start_listening()
+                self.do_sleep()
+                return
+            children.append(child_pid)
+
+        # Install a SIGTERM handler if requested
+        if not self.ignore_sigterm:
+            signal.signal(signal.SIGTERM, self.sigterm_handler)
+
+        self.child_pids = children
+        if self.parent_must_listen:
+            self.start_listening()
+        self.do_sleep()
+
+    def sigterm_handler(self, signum, frame):
+        if self.listen_socket:
+            self.listen_socket.close()
+        for child in self.child_pids:
+            try:
+                os.kill(child, signal.SIGTERM)
+            except OSError:
+                pass
+        sys.exit(0)
+
+
+def main():
+    cfg.CONF.register_cli_opts(OPTS)
+    cfg.CONF(project='neutron', default_config_files=[])
+    proc_spawn = ProcessSpawn(num_children=cfg.CONF.num_children,
+                      family=cfg.CONF.family,
+                      proto=cfg.CONF.proto,
+                      parent_must_listen=cfg.CONF.parent_listen,
+                      ignore_sigterm=cfg.CONF.ignore_sigterm)
+    proc_spawn.start()
+
+
+if __name__ == "__main__":
+    main()

neutron/tests/functional/cmd/test_netns_cleanup.py

@@ -13,19 +13,26 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import os
+
 import mock
+from neutron_lib import constants as n_const
 
 from neutron.agent.l3 import agent as l3_agent
 from neutron.agent.linux import dhcp
 from neutron.agent.linux import ip_lib
+from neutron.agent.linux import utils
 from neutron.cmd import netns_cleanup
+from neutron.common import utils as common_utils
 from neutron.conf.agent import cmd
 from neutron.tests import base as basetest
 from neutron.tests.common import net_helpers
 from neutron.tests.functional import base
+from neutron.tests.functional.cmd import process_spawn
 
 GET_NAMESPACES = 'neutron.agent.linux.ip_lib.IPWrapper.get_namespaces'
 TEST_INTERFACE_DRIVER = 'neutron.agent.linux.interface.OVSInterfaceDriver'
+NUM_SUBPROCESSES = 6
 
 
 class NetnsCleanupTest(base.BaseSudoTestCase):
@@ -60,13 +67,82 @@ class NetnsCleanupTest(base.BaseSudoTestCase):
         # tests, as otherwise cleanup will kill them all
         self.get_namespaces.return_value = [l3_namespace, dhcp_namespace]
 
+        # launch processes in each namespace to make sure they're
+        # killed during cleanup
+        procs_launched = self._launch_processes([l3_namespace, dhcp_namespace])
+        self.assertIsNot(procs_launched, 0)
+        common_utils.wait_until_true(
+            lambda: self._get_num_spawned_procs() == procs_launched,
+            timeout=15,
+            exception=Exception("Didn't spawn expected number of processes"))
+
         netns_cleanup.cleanup_network_namespaces(self.conf)
 
         self.get_namespaces_p.stop()
         namespaces_now = ip_lib.IPWrapper.get_namespaces()
+        procs_after = self._get_num_spawned_procs()
+        self.assertEqual(procs_after, 0)
         self.assertNotIn(l3_namespace, namespaces_now)
         self.assertNotIn(dhcp_namespace, namespaces_now)
 
+    @staticmethod
+    def _launch_processes(namespaces):
+        """
+        Launch processes in the specified namespaces.
+
+        This function will spawn processes inside the given namespaces:
+                - 6 processes listening on tcp ports (parent + 5 children)
+                - 1 process + 5 subprocesses listening on unix sockets
+                - 1 process + 5 subprocesses listening on udp6 sockets
+
+        First two sets of processes will process SIGTERM so when the parent
+        gets killed, it will kill all spawned children
+        The last set of processes will ignore SIGTERM. This will allow us
+        to test the cleanup functionality which will issue a SIGKILL
+        to all remaining processes after the SIGTERM attempt
+        """
+        commands = [['python', process_spawn.__file__,
+                     '-n', NUM_SUBPROCESSES,
+                     '-f', n_const.IPv4,
+                     '-p', n_const.PROTO_NAME_TCP,
+                     '--noignore_sigterm',
+                     '--parent_listen'],
+                    ['python', process_spawn.__file__,
+                     '-n', NUM_SUBPROCESSES,
+                     '-f', process_spawn.UNIX_FAMILY,
+                     '-p', n_const.PROTO_NAME_TCP,
+                     '--noignore_sigterm',
+                     '--noparent_listen'],
+                    ['python', process_spawn.__file__,
+                     '-n', NUM_SUBPROCESSES,
+                     '-f', n_const.IPv4,
+                     '-p', n_const.PROTO_NAME_UDP,
+                     '--ignore_sigterm',
+                     '--noparent_listen']]
+
+        proc_count = 0
+        for netns in namespaces:
+            ip = ip_lib.IPWrapper(namespace=netns)
+            for command in commands:
+                # The total amount of processes per command is
+                # the process itself plus the number of subprocesses spawned by
+                # it
+                proc_count += (1 + NUM_SUBPROCESSES)
+                # We need to pass the PATH env variable so that python
+                # interpreter runs under the same virtual environment.
+                # Otherwise, it won't find the necessary packages such as
+                # oslo_config
+                ip.netns.execute(command,
+                                 addl_env={'PATH':
+                                           os.environ.get('PATH')})
+        return proc_count
+
+    @staticmethod
+    def _get_num_spawned_procs():
+        cmd = ['ps', '-f', '-u', 'root']
+        out = utils.execute(cmd, run_as_root=True)
+        return sum([1 for line in out.splitlines() if 'process_spawn' in line])
+
 
 class TestNETNSCLIConfig(basetest.BaseTestCase):
 

neutron/tests/unit/agent/linux/test_async_process.py

@@ -198,20 +198,18 @@ class TestAsyncProcess(base.BaseTestCase):
             exc = RuntimeError(exception_message)
         else:
             exc = None
-        with mock.patch.object(utils, 'execute',
-                               side_effect=exc) as mock_execute:
+        with mock.patch.object(utils, 'kill_process',
+                               side_effect=exc) as mock_kill_process:
             actual = self.proc._kill_process(pid, kill_signal)
 
         self.assertEqual(expected, actual)
-        mock_execute.assert_called_with(['kill', '-%d' % kill_signal, pid],
-                                        run_as_root=self.proc.run_as_root)
+        mock_kill_process.assert_called_with(pid,
+                                             kill_signal,
+                                             self.proc.run_as_root)
 
     def test__kill_process_returns_true_for_valid_pid(self):
         self._test__kill_process('1', True)
 
-    def test__kill_process_returns_true_for_stale_pid(self):
-        self._test__kill_process('1', True, 'No such process')
-
     def test__kill_process_returns_false_for_execute_exception(self):
         self._test__kill_process('1', False, 'Invalid')
 

neutron/tests/unit/agent/linux/test_utils.py

@@ -12,6 +12,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import signal
 import socket
 
 import mock
@@ -181,6 +182,100 @@ class AgentUtilsGetInterfaceMAC(base.BaseTestCase):
         self.assertEqual(actual_val, expect_val)
 
 
+class TestFindParentPid(base.BaseTestCase):
+    def setUp(self):
+        super(TestFindParentPid, self).setUp()
+        self.m_execute = mock.patch.object(utils, 'execute').start()
+
+    def test_returns_none_for_no_valid_pid(self):
+        self.m_execute.side_effect = utils.ProcessExecutionError('',
+                                                                 returncode=1)
+        self.assertIsNone(utils.find_parent_pid(-1))
+
+    def test_returns_parent_id_for_good_ouput(self):
+        self.m_execute.return_value = '123 \n'
+        self.assertEqual(utils.find_parent_pid(-1), '123')
+
+    def test_raises_exception_returncode_0(self):
+        with testtools.ExpectedException(utils.ProcessExecutionError):
+            self.m_execute.side_effect = \
+                utils.ProcessExecutionError('', returncode=0)
+            utils.find_parent_pid(-1)
+
+    def test_raises_unknown_exception(self):
+        with testtools.ExpectedException(RuntimeError):
+            self.m_execute.side_effect = RuntimeError()
+            utils.find_parent_pid(-1)
+
+
+class TestFindForkTopParent(base.BaseTestCase):
+    def _test_find_fork_top_parent(self, expected=_marker,
+                                   find_parent_pid_retvals=None,
+                                   pid_invoked_with_cmdline_retvals=None):
+        def _find_parent_pid(x):
+            if find_parent_pid_retvals:
+                return find_parent_pid_retvals.pop(0)
+
+        pid_invoked_with_cmdline = {}
+        if pid_invoked_with_cmdline_retvals:
+            pid_invoked_with_cmdline['side_effect'] = (
+                pid_invoked_with_cmdline_retvals)
+        else:
+            pid_invoked_with_cmdline['return_value'] = False
+        with mock.patch.object(utils, 'find_parent_pid',
+                               side_effect=_find_parent_pid), \
+                mock.patch.object(utils, 'pid_invoked_with_cmdline',
+                                  **pid_invoked_with_cmdline):
+                    actual = utils.find_fork_top_parent(_marker)
+        self.assertEqual(expected, actual)
+
+    def test_returns_own_pid_no_parent(self):
+        self._test_find_fork_top_parent()
+
+    def test_returns_own_pid_nofork(self):
+        self._test_find_fork_top_parent(find_parent_pid_retvals=['2', '3'])
+
+    def test_returns_first_parent_pid_fork(self):
+        self._test_find_fork_top_parent(
+            expected='2',
+            find_parent_pid_retvals=['2', '3', '4'],
+            pid_invoked_with_cmdline_retvals=[True, False, False])
+
+    def test_returns_top_parent_pid_fork(self):
+        self._test_find_fork_top_parent(
+            expected='4',
+            find_parent_pid_retvals=['2', '3', '4'],
+            pid_invoked_with_cmdline_retvals=[True, True, True])
+
+
+class TestKillProcess(base.BaseTestCase):
+    def _test_kill_process(self, pid, exception_message=None,
+                           kill_signal=signal.SIGKILL):
+        if exception_message:
+            exc = utils.ProcessExecutionError(exception_message, returncode=0)
+        else:
+            exc = None
+        with mock.patch.object(utils, 'execute',
+                               side_effect=exc) as mock_execute:
+            utils.kill_process(pid, kill_signal, run_as_root=True)
+
+        mock_execute.assert_called_with(['kill', '-%d' % kill_signal, pid],
+                                        run_as_root=True)
+
+    def test_kill_process_returns_none_for_valid_pid(self):
+        self._test_kill_process('1')
+
+    def test_kill_process_returns_none_for_stale_pid(self):
+        self._test_kill_process('1', 'No such process')
+
+    def test_kill_process_raises_exception_for_execute_exception(self):
+        with testtools.ExpectedException(utils.ProcessExecutionError):
+            self._test_kill_process('1', 'Invalid')
+
+    def test_kill_process_with_different_signal(self):
+        self._test_kill_process('1', kill_signal=signal.SIGTERM)
+
+
 class TestFindChildPids(base.BaseTestCase):
 
     def test_returns_empty_list_for_exit_code_1(self):
@@ -197,6 +292,14 @@ class TestFindChildPids(base.BaseTestCase):
         with mock.patch.object(utils, 'execute', return_value=' 123 \n 185\n'):
             self.assertEqual(utils.find_child_pids(-1), ['123', '185'])
 
+    def test_returns_list_of_child_process_ids_recursively(self):
+        with mock.patch.object(utils, 'execute',
+                               side_effect=[' 123 \n 185\n',
+                                            ' 40 \n', '\n',
+                                            '41\n', '\n']):
+            actual = utils.find_child_pids(-1, True)
+            self.assertEqual(actual, ['123', '185', '40', '41'])
+
     def test_raises_unknown_exception(self):
         with testtools.ExpectedException(RuntimeError):
             with mock.patch.object(utils, 'execute',

neutron/tests/unit/cmd/test_netns_cleanup.py

@@ -13,11 +13,47 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import signal
+
 import mock
+import testtools
 
 from neutron.cmd import netns_cleanup as util
 from neutron.tests import base
 
+NETSTAT_NETNS_OUTPUT = ("""
+Active Internet connections (only servers)
+Proto Recv-Q Send-Q Local Address           Foreign Address         State\
+       PID/Program name
+tcp        0      0 0.0.0.0:9697            0.0.0.0:*               LISTEN\
+      1347/python
+raw        0      0 0.0.0.0:112             0.0.0.0:*               7\
+           1279/keepalived
+raw        0      0 0.0.0.0:112             0.0.0.0:*               7\
+           1279/keepalived
+raw6       0      0 :::58                   :::*                    7\
+           1349/radvd
+Active UNIX domain sockets (only servers)
+Proto RefCnt Flags       Type       State         I-Node   PID/Program name\
+     Path
+unix  2      [ ACC ]     STREAM     LISTENING     82039530 1353/python\
+          /tmp/rootwrap-VKSm8a/rootwrap.sock
+""")
+
+NETSTAT_NO_NAMESPACE = ("""
+Cannot open network namespace "qrouter-e6f206b2-4e8d-4597-a7e1-c3a20337e9c6":\
+ No such file or directory
+""")
+
+NETSTAT_NO_LISTEN_PROCS = ("""
+Active Internet connections (only servers)
+Proto Recv-Q Send-Q Local Address           Foreign Address         State\
+       PID/Program name
+Active UNIX domain sockets (only servers)
+Proto RefCnt Flags       Type       State         I-Node   PID/Program name\
+     Path
+""")
+
 
 class TestNetnsCleanup(base.BaseTestCase):
     def setUp(self):
@@ -163,6 +199,115 @@ class TestNetnsCleanup(base.BaseTestCase):
                     self.assertEqual([], ovs_br_cls.mock_calls)
                     self.assertTrue(debug.called)
 
+    def _test_find_listen_pids_namespace_helper(self, expected,
+                                                netstat_output=None):
+        with mock.patch('neutron.agent.linux.ip_lib.IPWrapper') as ip_wrap:
+            ip_wrap.return_value.netns.execute.return_value = netstat_output
+            observed = util.find_listen_pids_namespace(mock.ANY)
+            self.assertEqual(expected, observed)
+
+    def test_find_listen_pids_namespace_correct_output(self):
+        expected = set(['1347', '1279', '1349', '1353'])
+        self._test_find_listen_pids_namespace_helper(expected,
+                                                     NETSTAT_NETNS_OUTPUT)
+
+    def test_find_listen_pids_namespace_no_procs(self):
+        expected = set()
+        self._test_find_listen_pids_namespace_helper(expected,
+                                                     NETSTAT_NO_LISTEN_PROCS)
+
+    def test_find_listen_pids_namespace_no_namespace(self):
+        expected = set()
+        self._test_find_listen_pids_namespace_helper(expected,
+                                                     NETSTAT_NO_NAMESPACE)
+
+    def _test__kill_listen_processes_helper(self, pids, parents, children,
+                                            kills_expected, force):
+        def _get_element(dct, x):
+            return dct.get(x, [])
+
+        def _find_childs(x, recursive):
+            return _get_element(children, x)
+
+        def _find_parent(x):
+            return _get_element(parents, x)
+
+        utils_mock = dict(
+            find_fork_top_parent=mock.DEFAULT,
+            find_child_pids=mock.DEFAULT,
+            get_cmdline_from_pid=mock.DEFAULT,
+            kill_process=mock.DEFAULT)
+
+        self.log_mock = mock.patch.object(util, 'LOG').start()
+        with mock.patch.multiple('neutron.agent.linux.utils', **utils_mock)\
+                as mocks:
+            mocks['find_fork_top_parent'].side_effect = _find_parent
+            mocks['find_child_pids'].side_effect = _find_childs
+
+            with mock.patch.object(util, 'find_listen_pids_namespace',
+                                   return_value=pids):
+                calls = []
+                for pid, sig in kills_expected:
+                    calls.append(mock.call(pid, sig, run_as_root=True))
+                util._kill_listen_processes(mock.ANY, force=force)
+                mocks['kill_process'].assert_has_calls(calls, any_order=True)
+
+    def test__kill_listen_processes_only_parents_force_false(self):
+        pids = ['4', '5', '6']
+        parents = {'4': '1', '5': '5', '6': '2'}
+        children = {}
+        kills_expected = [('1', signal.SIGTERM),
+                          ('5', signal.SIGTERM),
+                          ('2', signal.SIGTERM)]
+
+        self._test__kill_listen_processes_helper(pids, parents, children,
+                                                 kills_expected, False)
+
+    def test__kill_listen_processes_parents_and_childs(self):
+        pids = ['4', '5', '6']
+        parents = {'4': '1', '5': '2', '6': '3'}
+        children = {'1': ['4'], '2': ['5'], '3': ['6', '8', '7']}
+        kills_expected = [(str(x), signal.SIGKILL) for x in range(1, 9)]
+        self._test__kill_listen_processes_helper(pids, parents, children,
+                                                 kills_expected, True)
+
+    def test_kill_listen_processes(self):
+        with mock.patch.object(util, '_kill_listen_processes',
+                               return_value=1) as mock_kill_listen:
+            with mock.patch('neutron.common.utils.wait_until_true')\
+                    as wait_until_true_mock:
+                wait_until_true_mock.side_effect = [
+                    util.PidsInNamespaceException,
+                    None]
+                namespace = mock.ANY
+                util.kill_listen_processes(namespace)
+                mock_kill_listen.assert_has_calls(
+                    [mock.call(namespace, force=False),
+                     mock.call(namespace, force=True)])
+
+    def test_kill_listen_processes_still_procs(self):
+        with mock.patch.object(util, '_kill_listen_processes',
+                               return_value=1):
+            with mock.patch('neutron.common.utils.wait_until_true')\
+                    as wait_until_true_mock:
+                wait_until_true_mock.side_effect = (
+                    util.PidsInNamespaceException)
+                namespace = mock.ANY
+                with testtools.ExpectedException(
+                        util.PidsInNamespaceException):
+                    util.kill_listen_processes(namespace)
+
+    def test_kill_listen_processes_no_procs(self):
+        with mock.patch.object(util, '_kill_listen_processes',
+                               return_value=0) as mock_kill_listen:
+            with mock.patch('neutron.common.utils.wait_until_true')\
+                    as wait_until_true_mock:
+                namespace = mock.ANY
+                util.kill_listen_processes(namespace)
+                mock_kill_listen.assert_called_once_with(namespace,
+                                                         force=False)
+                self.assertFalse(wait_until_true_mock.called)
+
     def _test_destroy_namespace_helper(self, force, num_devices):
         ns = 'qrouter-6e322ac7-ab50-4f53-9cdc-d1d3c1164b6d'
         conf = mock.Mock()
@@ -182,23 +327,27 @@ class TestNetnsCleanup(base.BaseTestCase):
             ip_wrap.return_value.get_devices.return_value = devices
             ip_wrap.return_value.netns.exists.return_value = True
 
-            with mock.patch.object(util, 'unplug_device') as unplug:
+            with mock.patch.object(util, 'kill_listen_processes'):
 
-                with mock.patch.object(util, 'kill_dhcp') as kill_dhcp:
-                    util.destroy_namespace(conf, ns, force)
-                    expected = [mock.call(namespace=ns)]
+                with mock.patch.object(util, 'unplug_device') as unplug:
 
-                    if force:
-                        expected.extend([
-                            mock.call().netns.exists(ns),
-                            mock.call().get_devices(exclude_loopback=True)])
-                        self.assertTrue(kill_dhcp.called)
-                        unplug.assert_has_calls(
-                            [mock.call(conf, d) for d in
-                             devices[1:]])
+                    with mock.patch.object(util, 'kill_dhcp') as kill_dhcp:
+                        util.destroy_namespace(conf, ns, force)
+                        expected = [mock.call(namespace=ns)]
 
-                    expected.append(mock.call().garbage_collect_namespace())
-                    ip_wrap.assert_has_calls(expected)
+                        if force:
+                            expected.extend([
+                                mock.call().netns.exists(ns),
+                                mock.call().get_devices(
+                                    exclude_loopback=True)])
+                            self.assertTrue(kill_dhcp.called)
+                            unplug.assert_has_calls(
+                                [mock.call(conf, d) for d in
+                                 devices[1:]])
+
+                        expected.append(
+                            mock.call().garbage_collect_namespace())
+                        ip_wrap.assert_has_calls(expected)
 
     def test_destroy_namespace_empty(self):
         self._test_destroy_namespace_helper(False, 0)

releasenotes/notes/netns_cleanup_kill_procs-af88d8c47c07dd9c.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - A new mechanism has been added to netns_cleanup to
+    kill processes that are listening on any port/unix
+    socket within the namespace. This will try to kill
+    them gracefully via SIGTERM and, if they don't die,
+    then a SIGKILL will be sent to the remaining
+    processes to ensure a proper cleanup.

setup.cfg

@@ -36,6 +36,7 @@ data_files =
         etc/neutron/rootwrap.d/ipset-firewall.filters
         etc/neutron/rootwrap.d/l3.filters
         etc/neutron/rootwrap.d/linuxbridge-plugin.filters
+        etc/neutron/rootwrap.d/netns-cleanup.filters
         etc/neutron/rootwrap.d/openvswitch-plugin.filters
 scripts =
     bin/neutron-rootwrap-xen-dom0