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OpenStack Study: netns_cleanup_util.py

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# vim: tabstop=4 shiftwidth=4 softtabstop=4

# 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 re

import eventlet

from oslo.config import cfg

from neutron.agent.common import config as agent_config

from neutron.agent import dhcp_agent

from neutron.agent import l3_agent

from neutron.agent.linux import dhcp

from neutron.agent.linux import interface

from neutron.agent.linux import ip_lib

from neutron.agent.linux import ovs_lib

from neutron.api.v2 import attributes

from neutron.common import config

from neutron.openstack.common import importutils

from neutron.openstack.common import log as logging

LOG = logging.getLogger(__name__)

NS_MANGLING_PATTERN = ('(%s|%s)' % (dhcp.NS_PREFIX, l3_agent.NS_PREFIX) +

attributes.UUID_PATTERN)

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class FakeDhcpPlugin(object):

"""Fake RPC plugin to bypass any RPC calls."""

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def __getattribute__(self, name):

def fake_method(*args):

pass

return fake_method

def setup_conf():

"""Setup the cfg for the clean up utility.

Use separate setup_conf for the utility because there are many options

from the main config that do not apply during clean-up.

help=_('Delete the namespace by removing all devices.')),

]

conf = cfg.CONF

conf.register_cli_opts(cli_opts)

agent_config.register_interface_driver_opts_helper(conf)

agent_config.register_use_namespaces_opts_helper(conf)

agent_config.register_root_helper(conf)

conf.register_opts(dhcp.OPTS)

conf.register_opts(dhcp_agent.DhcpAgent.OPTS)

conf.register_opts(interface.OPTS)

return conf

def kill_dhcp(conf, namespace):

"""Disable DHCP for a network if DHCP is still active."""

root_helper = agent_config.get_root_helper(conf)

network_id = namespace.replace(dhcp.NS_PREFIX, '')

dhcp_driver = importutils.import_object(

conf.dhcp_driver,

conf=conf,

network=dhcp.NetModel(conf.use_namespaces, {'id': network_id}),

root_helper=root_helper,

plugin=FakeDhcpPlugin())

if dhcp_driver.active:

dhcp_driver.disable()

def eligible_for_deletion(conf, namespace, force=False):

"""Determine whether a namespace is eligible for deletion.

Eligibility is determined by having only the lo device or if force

is passed as a parameter.

"""

# filter out namespaces without UUID as the name

if not re.match(NS_MANGLING_PATTERN, namespace):

return False

root_helper = agent_config.get_root_helper(conf)

ip = ip_lib.IPWrapper(root_helper, namespace)

return force or ip.namespace_is_empty()

def unplug_device(conf, device):

try:

device.link.delete()

except RuntimeError:

root_helper = agent_config.get_root_helper(conf)

# Maybe the device is OVS port, so try to delete

bridge_name = ovs_lib.get_bridge_for_iface(root_helper, device.name)

if bridge_name:

bridge = ovs_lib.OVSBridge(bridge_name, root_helper)

bridge.delete_port(device.name)

else:

LOG.debug(_('Unable to find bridge for device: %s'), device.name)

def destroy_namespace(conf, namespace, force=False):

"""Destroy a given namespace.

If force is True, then dhcp (if it exists) will be disabled and all

devices will be forcibly removed.

"""

try:

root_helper = agent_config.get_root_helper(conf)

ip = ip_lib.IPWrapper(root_helper, namespace)

if force:

kill_dhcp(conf, namespace)

# NOTE: The dhcp driver will remove the namespace if is it empty,

# so a second check is required here.

if ip.netns.exists(namespace):

for device in ip.get_devices(exclude_loopback=True):

unplug_device(conf, device)

ip.garbage_collect_namespace()

except Exception:

LOG.exception(_('Error unable to destroy namespace: %s'), namespace)

def main():

"""Main method for cleaning up network namespaces.

This method will make two passes checking for namespaces to delete. The

process will identify candidates, sleep, and call garbage collect. The

garbage collection will re-verify that the namespace meets the criteria for

deletion (ie it is empty). The period of sleep and the 2nd pass allow

time for the namespace state to settle, so that the check prior deletion

will re-confirm the namespace is empty.

The utility is designed to clean-up after the forced or unexpected

termination of Neutron agents.

The --force flag should only be used as part of the cleanup of a devstack

installation as it will blindly purge namespaces and their devices. This

option also kills any lingering DHCP instances.

"""

eventlet.monkey_patch()

conf = setup_conf()

conf()

config.setup_logging(conf)

root_helper = agent_config.get_root_helper(conf)

# Identify namespaces that are candidates for deletion.

candidates = [ns for ns in

ip_lib.IPWrapper.get_namespaces(root_helper)

if eligible_for_deletion(conf, ns, conf.force)]

if candidates:

eventlet.sleep(2)

for namespace in candidates:

destroy_namespace(conf, namespace, conf.force)

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def fake_method(*args):

pass

return fake_method

def setup_conf():

"""Setup the cfg for the clean up utility.

Use separate setup_conf for the utility because there are many options

from the main config that do not apply during clean-up.

help=_('Delete the namespace by removing all devices.')),

]

conf = cfg.CONF

conf.register_cli_opts(cli_opts)

agent_config.register_interface_driver_opts_helper(conf)

agent_config.register_use_namespaces_opts_helper(conf)

agent_config.register_root_helper(conf)

conf.register_opts(dhcp.OPTS)

conf.register_opts(dhcp_agent.DhcpAgent.OPTS)

conf.register_opts(interface.OPTS)

return conf

def kill_dhcp(conf, namespace):

"""Disable DHCP for a network if DHCP is still active."""

root_helper = agent_config.get_root_helper(conf)

network_id = namespace.replace(dhcp.NS_PREFIX, '')

dhcp_driver = importutils.import_object(

conf.dhcp_driver,

conf=conf,

network=dhcp.NetModel(conf.use_namespaces, {'id': network_id}),

root_helper=root_helper,

plugin=FakeDhcpPlugin())

if dhcp_driver.active:

dhcp_driver.disable()

def eligible_for_deletion(conf, namespace, force=False):

"""Determine whether a namespace is eligible for deletion.

Eligibility is determined by having only the lo device or if force

is passed as a parameter.

"""

# filter out namespaces without UUID as the name

if not re.match(NS_MANGLING_PATTERN, namespace):

return False

root_helper = agent_config.get_root_helper(conf)

ip = ip_lib.IPWrapper(root_helper, namespace)

return force or ip.namespace_is_empty()

def unplug_device(conf, device):

try:

device.link.delete()

except RuntimeError:

root_helper = agent_config.get_root_helper(conf)

# Maybe the device is OVS port, so try to delete

bridge_name = ovs_lib.get_bridge_for_iface(root_helper, device.name)

if bridge_name:

bridge = ovs_lib.OVSBridge(bridge_name, root_helper)

bridge.delete_port(device.name)

else:

LOG.debug(_('Unable to find bridge for device: %s'), device.name)

def destroy_namespace(conf, namespace, force=False):

"""Destroy a given namespace.

If force is True, then dhcp (if it exists) will be disabled and all

devices will be forcibly removed.

"""

try:

root_helper = agent_config.get_root_helper(conf)

ip = ip_lib.IPWrapper(root_helper, namespace)

if force:

kill_dhcp(conf, namespace)

# NOTE: The dhcp driver will remove the namespace if is it empty,

# so a second check is required here.

if ip.netns.exists(namespace):

for device in ip.get_devices(exclude_loopback=True):

unplug_device(conf, device)

ip.garbage_collect_namespace()

except Exception:

LOG.exception(_('Error unable to destroy namespace: %s'), namespace)

def main():

"""Main method for cleaning up network namespaces.

This method will make two passes checking for namespaces to delete. The

process will identify candidates, sleep, and call garbage collect. The

garbage collection will re-verify that the namespace meets the criteria for

deletion (ie it is empty). The period of sleep and the 2nd pass allow

time for the namespace state to settle, so that the check prior deletion

will re-confirm the namespace is empty.

The utility is designed to clean-up after the forced or unexpected

termination of Neutron agents.

The --force flag should only be used as part of the cleanup of a devstack

installation as it will blindly purge namespaces and their devices. This

option also kills any lingering DHCP instances.

"""

eventlet.monkey_patch()

conf = setup_conf()

conf()

config.setup_logging(conf)

root_helper = agent_config.get_root_helper(conf)

# Identify namespaces that are candidates for deletion.

candidates = [ns for ns in

ip_lib.IPWrapper.get_namespaces(root_helper)

if eligible_for_deletion(conf, ns, conf.force)]

if candidates:

eventlet.sleep(2)

for namespace in candidates:

destroy_namespace(conf, namespace, conf.force)