""" 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.iterkeys() for role in config.get('clients', None): (remote,) = ctx.cluster.only(role).remotes.iterkeys() 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.iterkeys() delete_dev(remote, config.get('iface'))