Add script to aid in using ovn-trace with OpenStack

This adds a script that allows one to pass in OpenStack objects
to fill in the eth/ip src/dst data when running ovn-trace. e.g.

  $ ml2ovn-trace --from server=vm1 --to server=vm2

or

 $ ml2ovn-trace --from server=vm1 --ip-dst 8.8.8.8 --via router=r1

Change-Id: I05c4eeee8d9cdb8faee2ee2eee166b421482173f
This commit is contained in:
Terry Wilson 2021-03-23 14:15:38 +00:00
parent 2980a962a0
commit 028c544b05
4 changed files with 366 additions and 0 deletions

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@ -11,4 +11,5 @@ OVN Driver
migration.rst
gaps.rst
dhcp_opts.rst
ml2ovn_trace.rst
faq/index.rst

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@ -0,0 +1,77 @@
.. _ml2ovn_trace:
ml2ovn-trace
============
This is a simple wrapper around ovn-trace that will fill in datapath, inport,
eth.src, ip.src, eth.dst, and ip.dst based on values pulled from openstack
objects.
Usage
-----
.. code-block:: console
Usage: ml2ovn-trace [OPTIONS] [OVNTRACE_ARGS]...
Options:
-c, --cloud TEXT Cloud from clouds.yaml to connect to
-n, --net TEXT Network to limit interfaces lookups to
--from-net TEXT Network to limit src interface lookups to
--to-net TEXT Network to limit dst interface lookups to
-f, --from [server|router]=value
Fill eth-src/ip-src from the same object,
e.g. server=vm1
--eth-src [mac|server|router]=value
Object from which to fill eth.src
[required]
--ip-src [ip|server|router]=value
Object from which to fill ip.src [required]
-t, --to [server|router]=value Fill eth-dst/ip-dst from the same object,
e.g. server=vm2
-v, --eth-dst, --via [mac|server|router]=value
Object from which to fill eth.dst
[required]
--ip-dst [ip|server|router]=value
Object from which to fill ip.dst [required]
-m, --microflow TEXT Additional microflow text to append to the
one generated
-v, --verbose Enables verbose mode
--dry-run Print ovn-trace output, but don't run it
--help Show this message and exit.
Examples
--------
If vm1 and vm2 only have one network interface and you want to trace between them:
.. code-block:: console
$ sudo ml2ovn-trace --from server=vm1 --to server=vm2
Or if you want to limit to a specific network:
.. code-block:: console
$ sudo ml2ovn-trace --net net1 --from server=vm1 --to server=vm2
Or if you want to go from vm1 to the floating IP of vm2 via vm1's router:
.. code-block:: console
$ sudo ml2ovn-trace --net net1 --from server=vm1 --to ip=172.18.1.7 --via router=net1-router
To add to the generated microflow, use -m. For example, for SSH:
.. code-block:: console
$ sudo ml2ovn-trace --net net1 --from server=vm1 --to server=vm2 -m "tcp.dst==22"
To pass arbitrary (non microflow) arguments to ovn-trace, place them after '--':
.. code-block:: console
$ sudo ml2ovn-trace --net net1 --from server=vm1 --to server=vm2 -- --summary

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@ -0,0 +1,287 @@
# Copyright 2021 Red Hat, Inc.
# All Rights Reserved.
#
# 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 ipaddress
import subprocess # nosec
import sys
import click
import openstack
from neutron._i18n import _
class cached_property:
__slots__ = ('_fn', '__doc__')
def __init__(self, fn):
self._fn = fn
self.__doc__ = fn.__doc__
def __get__(self, obj, objtype=None):
# class of wrapped method must have writable __dict__
attr = self._fn(obj)
setattr(obj, self._fn.__name__, attr)
return attr
class OvnTrace:
def __init__(self, eth_src_obj, ip_src_obj, eth_dst_obj, ip_dst_obj,
extra_flow, extra_args):
self.inport = eth_src_obj.inport
self.eth_src = eth_src_obj.mac
self.ip_src = ip_src_obj.ip
self.eth_dst = eth_dst_obj.mac
self.ip_dst = ip_dst_obj.ip
self.extra_flow = extra_flow
self.extra_args = extra_args
@property
def microflow(self):
ip_version = ipaddress.ip_address(self.ip_src).version
generated_flow = (
'inport == "{inport}" && '
'eth.src == {eth_src} && '
'ip{ip_src_v}.src == {ip_src} && '
'eth.dst == {eth_dst} && '
'ip{ip_dst_v}.dst == {ip_dst} && '
'ip.ttl == 64'.format(
inport=self.inport, eth_src=self.eth_src, ip_src_v=ip_version,
ip_src=self.ip_src, eth_dst=self.eth_dst, ip_dst_v=ip_version,
ip_dst=self.ip_dst))
return ' && '.join(f for f in (generated_flow, self.extra_flow) if f)
@property
def args(self):
return ('ovn-trace', *self.extra_args, self.microflow)
def run(self):
return subprocess.run(self.args, check=True) # nosec
def __str__(self):
return " ".join(self.args[:-1] + ("'%s'" % self.args[-1],))
class Interface:
def __init__(self, query, direction, ctx):
# Only store the state for running the queries, we don't want to
# make network connections until after argument parsing is done
self.query = query
self.direction = direction
self.ctx = ctx
@property
def network_param(self):
return (self.ctx.params.get('%s_net' % self.direction) or
self.ctx.params['net'])
@property
def cloud(self):
return self.ctx.cloud
class ServerInterface(Interface):
def get_iface(self, iface_type):
return next(iter(i for i in self.instance.addresses[self.network]
if i.get('OS-EXT-IPS:type') == iface_type))
@cached_property
def instance(self):
matching_vms = self.cloud.search_servers(self.query)
if len(matching_vms) < 1:
raise Exception(_('Server not found'))
if len(matching_vms) > 1:
raise Exception(_('Multiple VMs match %s' % self.query))
return matching_vms[0]
@cached_property
def network(self):
if self.network_param:
return self.network_param
if len(self.instance.addresses) != 1:
raise Exception(_("Could not determine server network"))
return next(iter(key for key in self.instance.addresses))
@cached_property
def inport(self):
return self.cloud.search_ports(
filters={'device_id': self.instance.id})[0].id
@cached_property
def ip(self):
iface = self.get_iface('fixed')
return iface['addr']
@cached_property
def mac(self):
iface = self.get_iface('fixed')
return iface['OS-EXT-IPS-MAC:mac_addr']
@cached_property
def floating_ip(self):
iface = self.get_iface('floating')
return iface['addr']
class RouterInterface(Interface):
@cached_property
def network(self):
return self.cloud.search_networks(self.network_param)[0]
@cached_property
def router(self):
return self.cloud.search_routers(self.query)[0]
@cached_property
def interface(self):
return next(iter(self.cloud.search_ports(
filters={'device_id': self.router.id,
'network_id': self.network.id})))
@cached_property
def inport(self):
return self.interface.id
@cached_property
def ip(self):
return next(iter(ip['ip_address'] for ip in self.interface.fixed_ips))
@cached_property
def mac(self):
return self.interface.mac_address
class SwitchPort(Interface):
cache = {}
class IP(Interface):
@property
def ip(self):
return self.query
class MAC(Interface):
@property
def mac(self):
return self.query
class RequiredUnless(click.Option):
def __init__(self, *args, **kwargs):
try:
self.unless = kwargs.pop('unless')
kwargs['required'] = True
except KeyError:
raise TypeError(_("Missing required argument: 'unless'"))
super().__init__(*args, **kwargs)
def handle_parse_result(self, ctx, opts, args):
if self.unless in opts:
self.required = False
return super().handle_parse_result(ctx, opts, args)
class ObjEqValueParam(click.ParamType):
types = {}
name = "object=value"
default_type = ""
def __init__(self, direction):
if direction not in ('from', 'to'):
raise ValueError(_("Direction must be 'from' or 'to'"))
self.direction = direction
super().__init__()
def get_metavar(self, param):
return "[{}]=value".format("|".join(self.types.keys()))
def convert(self, value, param, ctx):
if isinstance(value, self.__class__):
return value
try:
obj, value = value.split('=')
except ValueError:
obj = self.default_type
try:
return self.types[obj](value, self.direction, ctx)
except KeyError:
self.fail(f"Unkown object type {obj!r}", param, ctx)
class ToFromParam(ObjEqValueParam):
types = {'server': ServerInterface, 'router': RouterInterface}
default_type = 'server'
class MacParam(ObjEqValueParam):
types = dict(mac=MAC, **ToFromParam.types)
default_type = "mac"
class IpParam(ObjEqValueParam):
types = dict(ip=IP, **ToFromParam.types)
default_type = "ip"
def set_cloud(ctx, param, value):
ctx.cloud = openstack.connect(cloud=value)
return ctx.cloud
FromOpt = ToFromParam('from')
ToOpt = ToFromParam('to')
IpSrcOpt = IpParam('from')
EthSrcOpt = MacParam('from')
IpDstOpt = IpParam('to')
EthDstOpt = MacParam('to')
@click.command()
@click.option('--cloud', '-c', default='devstack', callback=set_cloud,
help='Cloud from clouds.yaml to connect to')
@click.option('--net', '-n', help="Network to limit interfaces lookups to")
@click.option('--from-net', help="Network to limit src interface lookups to")
@click.option('--to-net', help="Network to limit dst interface lookups to")
@click.option('--from', '-f', 'from_', type=FromOpt,
help='Fill eth-src/ip-src from the same object, e.g. server=vm1')
@click.option('--eth-src', type=EthSrcOpt, cls=RequiredUnless, unless='from_',
help='Object from which to fill eth.src')
@click.option('--ip-src', type=IpSrcOpt, cls=RequiredUnless, unless='from_',
help='Object from which to fill ip.src')
@click.option('--to', '-t', type=ToOpt,
help='Fill eth-dst/ip-dst from the same object, e.g. server=vm2')
@click.option('--eth-dst', '--via', '-v', type=EthDstOpt, cls=RequiredUnless,
unless='to', help='Object from which to fill eth.dst')
@click.option('--ip-dst', type=IpDstOpt, cls=RequiredUnless, unless='to',
help='Object from which to fill ip.dst')
@click.option('--microflow', '-m', default='',
help='Additional microflow text to append to the one generated')
@click.option('--verbose', '-v', is_flag=True, help='Enables verbose mode')
@click.option('--dry-run', is_flag=True,
help="Print ovn-trace output, but don't run it")
@click.argument('ovntrace_args', nargs=-1, type=click.UNPROCESSED)
def main(cloud, net, from_net, to_net, from_, eth_src, ip_src, to, eth_dst,
ip_dst, microflow, verbose, dry_run, ovntrace_args):
ovn_trace = OvnTrace(eth_src or from_, ip_src or from_,
eth_dst or to, ip_dst or to, microflow, ovntrace_args)
if not dry_run:
if verbose:
sys.stderr.write("%s\n" % ovn_trace)
ovn_trace.run()
else:
print(ovn_trace)

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@ -61,6 +61,7 @@ console_scripts =
neutron-ovn-metadata-agent = neutron.cmd.eventlet.agents.ovn_metadata:main
neutron-ovn-migration-mtu = neutron.cmd.ovn.migration_mtu:main
neutron-ovn-db-sync-util = neutron.cmd.ovn.neutron_ovn_db_sync_util:main
ml2ovn-trace = neutron.cmd.ovn.ml2ovn_trace:main
neutron.core_plugins =
ml2 = neutron.plugins.ml2.plugin:Ml2Plugin
neutron.service_plugins =