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https://issues.apache.org/jira/browse/AURORA-1952?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16211737#comment-16211737
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Jordan Ly commented on AURORA-1952:
-----------------------------------
Hi [~mohitjaggi]!
It is possible for Mesos to send multiple offers for the same host in busy
scenarios. We acknowledge this in `OfferManagerImpl::addOffer`:
{noformat}
// We run a slight risk of a race here, which is acceptable. The worst
case is that we
// temporarily hold two offers for the same host, which should be
corrected when we return
// them after the return delay.
{noformat}
One scenario that can occur is that we hold two offers, but a rescind is issued
for one of them before we can compact them using return delay.
1. Aurora gets offer_1 for host_a
2. Aurora gets offer_2 for host_a
3. Aurora gets a rescind for offer_1
4. We remove offer_1 from HostOffers, but we also remove the AgentID and HostID
from their respective maps.
5. Aurora gets offer_3 for host_a and it seems like we do not have any offers
from that agent, despite the fact that we still have offer_2. We add the offer
and thus have 2 offers for the same agent.
One thing we can do is ensure that `HostOffers::remove` takes into account the
value to remove as well:
{noformat}
offersBySlave.remove(removed.getOffer().getAgentId()); // Add `,
removed` to args
offersByHost.remove(removed.getOffer().getHostname()); // Add `,
removed` to args
{noformat}
The race condition will still exist (but with a smaller probability). A longer
term solution would be to make `addOffer` synchronous in the sense that it will
decline the two offers for the same host no matter what. We are actually
running into this problem here: https://reviews.apache.org/r/63157/ so your
issue may be solved as a side-effect of this.
> race condition in offers by agent id map (and potentially others)
> caused(probably) a crash
> ------------------------------------------------------------------------------------------
>
> Key: AURORA-1952
> URL: https://issues.apache.org/jira/browse/AURORA-1952
> Project: Aurora
> Issue Type: Bug
> Components: Scheduler
> Affects Versions: 0.18.0
> Environment: nothing special
> Reporter: Mohit Jaggi
> Assignee: Mohit Jaggi
> Fix For: 0.18.0
>
>
> Crashed here
> https://github.com/apache/aurora/blob/master/src/main/java/org/apache/aurora/scheduler/preemptor/PendingTaskProcessor.java#L145
> due to duplicates in map. Most likely a concurrency issue. [~wfarner] pointed
> out the following code:
> I'm looking at this chunk here, where a concurrent map would not help.
> Optional<HostOffer> sameSlave =
> hostOffers.get(offer.getOffer().getAgentId());
> if (sameSlave.isPresent()) {
> // If there are existing offers for the slave, decline all of them so
> the master can
> // compact all of those offers into a single offer and send them back.
> LOG.info("Returning offers for " +
> offer.getOffer().getAgentId().getValue()
> + " for compaction.");
> decline(offer.getOffer().getId());
> removeAndDecline(sameSlave.get().getOffer().getId());
> } else {
> hostOffers.add(offer);
> --------- logs ----------
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: Sep 28, 2017 6:09:00 PM
> com.google.common.util.concurrent.ServiceManager$ServiceListener failed
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: SEVERE: Service
> PreemptorService [FAILED] has failed in the RUNNING state.
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]:
> java.lang.IllegalArgumentException: Multiple entries with same key:
> 1ed038e0-a3ef-4476-adfd-70c86241c5f7-S102=HostOffer{offer=id {
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: value:
> "f7b84805-a0c5-4405-be77-f7f1b7110405-O56597202"
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: }
> ...
> ...
> ep 28 18:09:00 machine1163 aurora-scheduler[14266]: ,
> hostAttributes=IHostAttributes{host=compute606-dca1.prod.uber.internal,
> attributes=[IAttribute{name=host, values=[compute606-dca1]},
> IAttribute{name=rack, values=[as13]}, IAttribute{name=pod, values=[d]},
> IAttribute{name=dedicated, values=[infra/cassandra]}], mode=NONE,
> slaveId=1ed038e0-a3ef-4476-adfd-70c86241c5f7-S102}}. To index multiple values
> under a key, use Multimaps.index.
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> com.google.common.collect.Maps.uniqueIndex(Maps.java:1251)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> com.google.common.collect.Maps.uniqueIndex(Maps.java:1208)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> org.apache.aurora.scheduler.preemptor.PendingTaskProcessor.lambda$run$0(PendingTaskProcessor.java:146)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> org.apache.aurora.scheduler.storage.db.DbStorage.read(DbStorage.java:147)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> org.mybatis.guice.transactional.TransactionalMethodInterceptor.invoke(TransactionalMethodInterceptor.java:101)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> org.apache.aurora.common.inject.TimedInterceptor.invoke(TimedInterceptor.java:83)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> org.apache.aurora.scheduler.storage.log.LogStorage.read(LogStorage.java:562)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> org.apache.aurora.scheduler.storage.CallOrderEnforcingStorage.read(CallOrderEnforcingStorage.java:113)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> org.apache.aurora.scheduler.preemptor.PendingTaskProcessor.run(PendingTaskProcessor.java:135)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> org.apache.aurora.common.inject.TimedInterceptor.invoke(TimedInterceptor.java:83)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> org.apache.aurora.scheduler.preemptor.PreemptorModule$PreemptorService.runOneIteration(PreemptorModule.java:161)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> com.google.common.util.concurrent.AbstractScheduledService$ServiceDelegate$Task.run(AbstractScheduledService.java:188)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> com.google.common.util.concurrent.Callables$4.run(Callables.java:122)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: at
> java.lang.Thread.run(Thread.java:748)
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: E0928 18:09:00.316
> [PreemptorService RUNNING, GuavaUtils$LifecycleShutdownListener:55] Service:
> PreemptorService [FAILED] failed unexpectedly. Triggering shutdown.
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: I0928 18:09:00.316
> [qtp1000734462-3068369, Slf4jRequestLog:60] 10.187.28.19 - -
> [28/Sep/2017:18:09:00 +0000] "POST //10.188.43.6:8082/api HTTP/1.1" 200 95
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: I0928 18:09:00.316
> [PreemptorService RUNNING, Lifecycle:84] Shutting down application
> Sep 28 18:09:00 machine1163 aurora-scheduler[14266]: I0928 18:09:00.316
> [PreemptorService RUNNING, ShutdownRegistry$ShutdownRegistryImpl:77]
> Executing 4 shutdown commands.
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