"""
Task to run tests with network delay between two remotes using tc and netem.
Reference:https://wiki.linuxfoundation.org/networking/netem.
"""
import logging
import contextlib
from teuthology import misc as teuthology
from cStringIO import StringIO
from teuthology.orchestra import run
from teuthology import contextutil
from paramiko import SSHException
import socket
import time
import gevent
import argparse
log = logging.getLogger(__name__)
def set_priority(interface):
# create a priority queueing discipline
return ['sudo', 'tc', 'qdisc', 'add', 'dev', interface, 'root', 'handle', '1:', 'prio']
def show_tc(interface):
# shows tc device present
return ['sudo', 'tc', 'qdisc', 'show', 'dev', interface]
def del_tc(interface):
return ['sudo', 'tc', 'qdisc', 'del', 'dev', interface, 'root']
def cmd_prefix(interface):
# prepare command to set delay
cmd1 = ['sudo', 'tc', 'qdisc', 'add', 'dev', interface, 'parent',
'1:1', 'handle', '2:', 'netem', 'delay']
# prepare command to change delay
cmd2 = ['sudo', 'tc', 'qdisc', 'replace', 'dev', interface, 'root', 'netem', 'delay']
# prepare command to apply filter to the matched ip/host
cmd3 = ['sudo', 'tc', 'filter', 'add', 'dev', interface,
'parent', '1:0', 'protocol', 'ip', 'pref', '55',
'handle', '::55', 'u32', 'match', 'ip', 'dst']
return cmd1, cmd2, cmd3
def static_delay(remote, host, interface, delay):
""" Sets a constant delay between two hosts to emulate network delays using tc qdisc and netem"""
set_delay, change_delay, set_ip = cmd_prefix(interface)
ip = socket.gethostbyname(host.hostname)
r = remote.run(args=show_tc(interface), stdout=StringIO())
if r.stdout.getvalue().strip().find('refcnt') == -1:
# call set_priority() func to create priority queue
# if not already created(indicated by -1)
log.info('Create priority queue')
remote.run(args=set_priority(interface))
# set static delay, with +/- 5ms jitter with normal distribution as default
log.info('Setting delay to %s' % delay)
set_delay.extend(['%s' % delay, '5ms', 'distribution', 'normal'])
remote.run(args=set_delay)
# set delay to a particular remote node via ip
log.info('Delay set on %s' % remote)
set_ip.extend(['%s' % ip, 'flowid', '2:1'])
remote.run(args=set_ip)
else:
# if the device is already created, only change the delay
log.info('Setting delay to %s' % delay)
change_delay.extend(['%s' % delay, '5ms', 'distribution', 'normal'])
remote.run(args=change_delay)
def variable_delay(remote, host, interface, delay_range=[]):
""" Vary delay between two values"""
set_delay, change_delay, set_ip = cmd_prefix(interface)
ip = socket.gethostbyname(host.hostname)
# delay1 has to be lower than delay2
delay1 = delay_range[0]
delay2 = delay_range[1]
r = remote.run(args=show_tc(interface), stdout=StringIO())
if r.stdout.getvalue().strip().find('refcnt') == -1:
# call set_priority() func to create priority queue
# if not already created(indicated by -1)
remote.run(args=set_priority(interface))
# set variable delay
log.info('Setting varying delay')
set_delay.extend(['%s' % delay1, '%s' % delay2])
remote.run(args=set_delay)
# set delay to a particular remote node via ip
log.info('Delay set on %s' % remote)
set_ip.extend(['%s' % ip, 'flowid', '2:1'])
remote.run(args=set_ip)
else:
# if the device is already created, only change the delay
log.info('Setting varying delay')
change_delay.extend(['%s' % delay1, '%s' % delay2])
remote.run(args=change_delay)
def delete_dev(remote, interface):
""" Delete the qdisc if present"""
log.info('Delete tc')
r = remote.run(args=show_tc(interface), stdout=StringIO())
if r.stdout.getvalue().strip().find('refcnt') != -1:
remote.run(args=del_tc(interface))
class Toggle:
stop_event = gevent.event.Event()
def __init__(self, ctx, remote, host, interface, interval):
self.ctx = ctx
self.remote = remote
self.host = host
self.interval = interval
self.interface = interface
self.ip = socket.gethostbyname(self.host.hostname)
def packet_drop(self):
""" Drop packets to the remote ip specified"""
_, _, set_ip = cmd_prefix(self.interface)
r = self.remote.run(args=show_tc(self.interface), stdout=StringIO())
if r.stdout.getvalue().strip().find('refcnt') == -1:
self.remote.run(args=set_priority(self.interface))
# packet drop to specific ip
log.info('Drop all packets to %s' % self.host)
set_ip.extend(['%s' % self.ip, 'action', 'drop'])
self.remote.run(args=set_ip)
def link_toggle(self):
"""
For toggling packet drop and recovery in regular interval.
If interval is 5s, link is up for 5s and link is down for 5s
"""
while not self.stop_event.is_set():
self.stop_event.wait(timeout=self.interval)
# simulate link down
try:
self.packet_drop()
log.info('link down')
except SSHException as e:
log.debug('Failed to run command')
self.stop_event.wait(timeout=self.interval)
# if qdisc exist,delete it.
try:
delete_dev(self.remote, self.interface)
log.info('link up')
except SSHException as e:
log.debug('Failed to run command')
def begin(self, gname):
self.thread = gevent.spawn(self.link_toggle)
self.ctx.netem.names[gname] = self.thread
def end(self, gname):
self.stop_event.set()
log.info('gname is {}'.format(self.ctx.netem.names[gname]))
self.ctx.netem.names[gname].get()
def cleanup(self):
"""
Invoked during unwinding if the test fails or exits before executing task 'link_recover'
"""
log.info('Clean up')
self.stop_event.set()
self.thread.get()
@contextlib.contextmanager
def task(ctx, config):
"""
- netem:
clients: [c1.rgw.0]
iface: eno1
dst_client: [c2.rgw.1]
delay: 10ms
- netem:
clients: [c1.rgw.0]
iface: eno1
dst_client: [c2.rgw.1]
delay_range: [10ms, 20ms] # (min, max)
- netem:
clients: [rgw.1, mon.0]
iface: eno1
gname: t1
dst_client: [c2.rgw.1]
link_toggle_interval: 10 # no unit mentioned. By default takes seconds.
- netem:
clients: [rgw.1, mon.0]
iface: eno1
link_recover: [t1, t2]
"""
log.info('config %s' % config)
assert isinstance(config, dict), \
"please list clients to run on"
if not hasattr(ctx, 'netem'):
ctx.netem = argparse.Namespace()
ctx.netem.names = {}
if config.get('dst_client') is not None:
dst = config.get('dst_client')
(host,) = ctx.cluster.only(dst).remotes.keys()
for role in config.get('clients', None):
(remote,) = ctx.cluster.only(role).remotes.keys()
ctx.netem.remote = remote
if config.get('delay', False):
static_delay(remote, host, config.get('iface'), config.get('delay'))
if config.get('delay_range', False):
variable_delay(remote, host, config.get('iface'), config.get('delay_range'))
if config.get('link_toggle_interval', False):
log.info('Toggling link for %s' % config.get('link_toggle_interval'))
global toggle
toggle = Toggle(ctx, remote, host, config.get('iface'), config.get('link_toggle_interval'))
toggle.begin(config.get('gname'))
if config.get('link_recover', False):
log.info('Recovering link')
for gname in config.get('link_recover'):
toggle.end(gname)
log.info('sleeping')
time.sleep(config.get('link_toggle_interval'))
delete_dev(ctx.netem.remote, config.get('iface'))
del ctx.netem.names[gname]
try:
yield
finally:
if ctx.netem.names:
toggle.cleanup()
for role in config.get('clients'):
(remote,) = ctx.cluster.only(role).remotes.keys()
delete_dev(remote, config.get('iface'))