Tim Harper created MESOS-8171:
---------------------------------
Summary: Using a failoverTimeout of 0 with Mesos native scheduler
client can result in infinite subscribe loop
Key: MESOS-8171
URL: https://issues.apache.org/jira/browse/MESOS-8171
Project: Mesos
Issue Type: Bug
Components: c++ api, java api, scheduler driver
Affects Versions: 1.4.0
Reporter: Tim Harper
Priority: Minor
Over the past year, the Marathon team has been plagued with an issue that hits
our CI builds periodically in which the scheduler driver enters a tight loop,
sending 10,000s of SUBSCRIBE calls to the master per second. I turned on debug
logging for the client and the server, and it pointed to an issue with the
{{doReliableRegistration}} method in sched.cpp. Here's the logs:
{code}
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.099815
13397 process.cpp:1383] libprocess is initialized on 127.0.1.1:60957 with 8
worker threads
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.118237
13397 logging.cpp:199] Logging to STDERR
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.128921
13416 sched.cpp:232] Version: 1.4.0
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.151785
13791 group.cpp:341] Group process (zookeeper-group(1)@127.0.1.1:60957)
connected to ZooKeeper
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.151823
13791 group.cpp:831] Syncing group operations: queue size (joins, cancels,
datas) = (0, 0, 0)
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.151837
13791 group.cpp:419] Trying to create path '/mesos' in ZooKeeper
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.152586
13791 group.cpp:758] Found non-sequence node 'log_replicas' at '/mesos' in
ZooKeeper
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.152662
13791 detector.cpp:152] Detected a new leader: (id='0')
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.152762
13791 group.cpp:700] Trying to get '/mesos/json.info_0000000000' in ZooKeeper
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.157148
13791 zookeeper.cpp:262] A new leading master ([email protected]:32856)
is detected
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.157347
13787 sched.cpp:336] New master detected at [email protected]:32856
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.157557
13787 sched.cpp:352] No credentials provided. Attempting to register without
authentication
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.157565
13787 sched.cpp:836] Sending SUBSCRIBE call to [email protected]:32856
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.157635
13787 sched.cpp:869] Will retry registration in 0ns if necessary
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.158979
13785 sched.cpp:836] Sending SUBSCRIBE call to [email protected]:32856
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159029
13785 sched.cpp:869] Will retry registration in 0ns if necessary
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159265
13790 sched.cpp:836] Sending SUBSCRIBE call to [email protected]:32856
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159303
13790 sched.cpp:869] Will retry registration in 0ns if necessary
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159479
13786 sched.cpp:836] Sending SUBSCRIBE call to [email protected]:32856
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159521
13786 sched.cpp:869] Will retry registration in 0ns if necessary
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159622
13788 sched.cpp:836] Sending SUBSCRIBE call to [email protected]:32856
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159658
13788 sched.cpp:869] Will retry registration in 0ns if necessary
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159749
13789 sched.cpp:836] Sending SUBSCRIBE call to [email protected]:32856
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159785
13789 sched.cpp:869] Will retry registration in 0ns if necessary
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159878
13792 sched.cpp:836] Sending SUBSCRIBE call to [email protected]:32856
WARN [05:39:39 EventsIntegrationTest-LocalMarathon-32858] I1104 05:39:39.159916
13792 sched.cpp:869] Will retry registration in 0ns if necessary
{code}
In Marathon, when we are running our tests, we set the failoverTimeout to 0 in
order to cause the Mesos master to immediately forget about a framework when it
disconnects.
On line 860 of sched.cpp, the retry-delay is set to 1/10th the failoverTimeout,
which provides the best explanation for why the value is 0:
{code}
/Users/tim/src/m8e/mesos/src/sched/sched.cpp
818 | void doReliableRegistration(Duration maxBackoff)
819 | {
...
851 | // Bound the maximum backoff by 'REGISTRATION_RETRY_INTERVAL_MAX'.
852 | maxBackoff =
853 | std::min(maxBackoff, scheduler::REGISTRATION_RETRY_INTERVAL_MAX);
854 |
855 | // If failover timeout is present, bound the maximum backoff
856 | // by 1/10th of the failover timeout.
857 | if (framework.has_failover_timeout()) {
858 | Try<Duration> duration =
Duration::create(framework.failover_timeout());
859 | if (duration.isSome()) {
860 | maxBackoff = std::min(maxBackoff, duration.get() / 10);
861 | }
862 | }
863 |
864 | // Determine the delay for next attempt by picking a random
865 | // duration between 0 and 'maxBackoff'.
866 | // TODO(vinod): Use random numbers from <random> header.
867 | Duration delay = maxBackoff * ((double) os::random() / RAND_MAX);
868 |
869 | VLOG(1) << "Will retry registration in " << delay << " if necessary";
870 |
871 | // Backoff.
872 | frameworkRegistrationTimer = process::delay(
873 | delay, self(), &Self::doReliableRegistration, maxBackoff * 2);
874 | }
875 |
{code}
Reading through the code, it seems that once this value is 0, it will always be
zero, since backoff is multiplicative.
Also, a separate issue, but, am I reading this wrong? It seems like maxBackoff
will always approach zero, since it is multiplied by a number between {{[0,
1.0]}}. Should it be adding this random amount, instead?
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