packstack/packstack/puppet/modules/packstack/lib/facter/netns.py

207 lines
7.5 KiB
Python

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import contextlib
import inspect
import os
import random
import subprocess
import sys
import tempfile
import uuid
import unittest
def execute(cmd_string, check_error=True, return_code=0, input=None,
block=True, error_msg='Error executing cmd'):
print cmd_string
cmd = cmd_string.split(' ')
proc = subprocess.Popen(cmd,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
if input:
proc.communicate(input=input)
elif block:
proc.wait()
if (check_error and
proc.returncode is not None and
proc.returncode != return_code):
msg = """
%(error_msg)s
Command: %(cmd)s
Exit Code: %(code)s
""".strip() % dict(cmd=' '.join(cmd),
code=proc.returncode,
error_msg=error_msg)
if input:
msg += "\n Stdin: %s" % input
if not proc.stdout.closed:
msg += "\n Stdout: %s" % proc.stdout.read()
if not proc.stderr.closed:
msg += "\n Stderr: %s" % proc.stderr.read()
raise Exception(msg)
return proc
def e(cmd, prefix='ip netns exec ', sudo=False, **kwargs):
frame_locals = inspect.getargvalues(sys._getframe(1))[3]
if sudo:
prefix = 'sudo ' + prefix
return execute(prefix + cmd % frame_locals, **kwargs)
def rand_name(name='test'):
return '%s-%s' % (name, str(random.randint(1, 0x7fffffff)))
@contextlib.contextmanager
def add_namespace():
name = rand_name('testns')
try:
e('ip netns add %(name)s', prefix='')
e('%(name)s ip link set lo up')
yield name
finally:
e('ip netns delete %(name)s', prefix='')
@contextlib.contextmanager
def add_namespaces():
with add_namespace() as ns1:
with add_namespace() as ns2:
yield ns1, ns2
def add_veth_pair(ns1, ns2, veth1, veth2, address1, address2):
e('ip link add %(veth1)s netns %(ns1)s type veth '
'peer name %(veth2)s netns %(ns2)s', prefix='')
e('%(ns1)s ip link show %(veth1)s')
e('%(ns2)s ip link show %(veth2)s')
e('%(ns1)s ip -4 addr add %(address1)s/24 brd 255.255.255.0 '
'scope global dev %(veth1)s')
e('%(ns2)s ip -4 addr add %(address2)s/24 brd 255.255.255.0 '
'scope global dev %(veth2)s')
e('%(ns1)s ip link set %(veth1)s up')
e('%(ns2)s ip link set %(veth2)s up')
class TestNetns(unittest.TestCase):
def test_neutron_netns_cmds(self):
"""Exercise the netns functionality required by neutron.
- Check that a veth pair can be configured to transit traffic
between 2 namespaces
- Check that iptables filtering can be configured
- Check that iptables routing can be configured
"""
# Naming scheme [resource][id]_[namespace id]
veth1_1 = 'veth1_1'
veth1_2 = 'veth1_2'
address1_1 = '192.168.0.1'
address1_2 = '192.168.0.2'
with add_namespaces() as (ns1, ns2):
# Check that inter-namespace connectivity can be established
add_veth_pair(ns1, ns2, veth1_1, veth1_2, address1_1, address1_2)
e('%(ns1)s ip link list')
e('%(ns1)s ip link show %(veth1_1)s')
e('%(ns1)s arping -A -U -I %(veth1_1)s '
'-c 1 %(address1_1)s')
e('%(ns2)s route add default gw %(address1_1)s')
e('%(ns2)s ping -c 1 -w 1 %(address1_1)s')
e('ping -c 1 -w 1 %(address1_1)s', prefix='', return_code=1,
error_msg='Namespace isolation not supported!')
# Check that iptables filtering and save/restore can be performed
try:
iptables_filename = os.path.join(
tempfile.gettempdir(),
'iptables-%s' % str(uuid.uuid4()))
e('%%(ns1)s iptables-save > %s' % iptables_filename)
e('%(ns1)s iptables -A INPUT -p icmp --icmp-type 8 -j DROP')
e('%(ns2)s ping -c 1 -w 1 %(address1_1)s', return_code=1)
e('%%(ns1)s iptables-restore < %s' % iptables_filename)
e('%(ns2)s ping -c 1 -w 1 %(address1_1)s')
finally:
if os.path.exists(iptables_filename):
os.unlink(iptables_filename)
# Create another namespace (ns3) that is connected to ns1
# via a different subnet, so that traffic between ns3 and
# ns2 will have to be routed by ns1:
#
# ns2 <- 192.168.0.0/24 -> ns1 <- 192.168.1.0/24 -> ns3
#
with add_namespace() as ns3:
veth2_1 = 'veth2_1'
veth2_3 = 'veth2_3'
address2_1 = '192.168.1.1'
address2_3 = '192.168.1.2'
add_veth_pair(ns1, ns3, veth2_1, veth2_3,
address2_1, address2_3)
e('%(ns1)s sysctl -w net.ipv4.ip_forward=1')
e('%(ns1)s iptables -t nat -A POSTROUTING -o %(veth2_1)s -j '
'MASQUERADE')
e('%(ns1)s iptables -A FORWARD -i %(veth2_1)s -o %(veth1_1)s '
'-m state --state RELATED,ESTABLISHED -j ACCEPT')
e('%(ns1)s iptables -A FORWARD -i %(veth1_1)s -o %(veth2_1)s '
'-j ACCEPT')
e('%(ns2)s ping -c 1 -w 1 %(address2_3)s')
# Check that links can be torn down
e('%(ns1)s ip -4 addr del %(address1_1)s/24 '
'dev %(veth1_1)s')
e('%(ns1)s ip link delete %(veth1_1)s')
def test_domain_socket_access(self):
"""Check that a domain socket can be accessed regardless of namespace.
Neutron extends nova' metadata service - which identifies VM's
by their ip addresses - to configurations with overlapping
ips. Support is provided by:
- a proxy in each namespace (neutron-ns-metadata-proxy)
- the proxy can uniquely identify a given VM by its ip
address in the context of the router or network of the
namespace.
- a metadata agent (neutron-metadata-agent) that forwards
requests from the namespace proxies to nova's metadata
service.
Communication between the proxies and the agent is over a unix
domain socket. It is necessary that access to a domain socket
not be restricted by namespace, or such communication will not
be possible.
"""
try:
execute('which nc')
except Exception:
self.fail("The 'nc' command is not available - please install it.")
sock_filename = os.path.join(tempfile.gettempdir(),
'testsock-%s' % str(uuid.uuid4()))
server = None
try:
# Create a server in the root namespace attached to a domain socket
server = e('nc -lU %(sock_filename)s', sudo=False, prefix='',
block=False)
# Attempt to connect to the domain socket from within a namespace
with add_namespace() as ns:
e('%(ns)s nc -U %(sock_filename)s', input='magic',
error_msg='Unable to communicate between namespaces via '
'domain sockets.')
finally:
if server:
server.kill()
if os.path.exists(sock_filename):
os.unlink(sock_filename)
if __name__ == '__main__':
unittest.main()