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From Todd Palino <tpal...@gmail.com>
Subject Re: Log Cleaner Thread Stops
Date Fri, 25 Sep 2015 04:15:22 GMT
For now, that's the way it is. Historically, we've only monitored the lag
for our infrastructure applications. Other users are responsible for their
own checking, typically using the maxlag mbean or some application specific
metric. Besides the core, we've probably got a dozen or so consumers moved
over to Kafka committed offsets at this point.

Of course, just those apps do cover well over a hundred consumer groups :)

-Todd

On Thursday, September 24, 2015, James Cheng <jcheng@tivo.com> wrote:

>
> > On Sep 24, 2015, at 8:11 PM, Todd Palino <tpalino@gmail.com
> <javascript:;>> wrote:
> >
> > Well, in general you can't currently use compressed messages in any topic
> > that has compaction turned on regardless of whether or not you are using
> > Kafka-committed offsets. The log compaction thread will die either way.
> > There's only one compression thread for the broker that runs on all
> topics
> > that use compaction.
> >
> > Jason, to address your question, it's probably wise to wait for now.
> > Zookeeper offsets work, so unless it's broke, don't fix it for now. We're
> > using Kafka-committed offsets at LinkedIn for our mirror makers and our
> > auditor application (both of which are considered infrastructure
> > applications for Kafka), but we're not encouraging other internal users
> to
> > switch over just yet.
> >
>
> Burrow depends on kafka-commited offsets, doesn’t it? I guess that means
> Burrow is only being used to monitor your mirror makers and auditor
> application, then?
>
> -James
>
> > -Todd
> >
> >
> > On Wed, Sep 23, 2015 at 3:21 PM, James Cheng <jcheng@tivo.com
> <javascript:;>> wrote:
> >
> >>
> >> On Sep 18, 2015, at 10:25 AM, Todd Palino <tpalino@gmail.com
> <javascript:;>> wrote:
> >>
> >>> I think the last major issue with log compaction (that it couldn't
> handle
> >>> compressed messages) was committed as part of
> >>> https://issues.apache.org/jira/browse/KAFKA-1374 in August, but I'm
> not
> >>> certain what version this will end up in. It may be part of 0.8.2.2.
> >>>
> >>> Regardless, you'll probably be OK now. We've found that once we clean
> >> this
> >>> issue up once it doesn't appear to recur. As long as you're not writing
> >> in
> >>> compressed messages to a log compacted topic (and that won't happen
> with
> >>> __consumer_offsets, as it's managed by the brokers themselves - it
> would
> >>> only be if you were using other log compacted topics), you're likely in
> >> the
> >>> clear now.
> >>>
> >>
> >> Todd,
> >>
> >> If I understand your description of the problem, you are saying that
> >> enabling log compaction on a topic with compressed messages can (will?)
> >> cause the log cleaner to crash when it encounters those compressed
> >> messages. And the death of the cleaner thread will prevent log
> compaction
> >> from running on other topics, even ones that don't have compressed
> messages.
> >>
> >> That means if we have a cluster where we want to use log compaction on
> >> *any* topic, we need to either:
> >> 1) apply https://issues.apache.org/jira/browse/KAFKA-1374 (or upgrade
> to
> >> some version it is applied)
> >> OR
> >> 2) make sure that we don't use compressed messages in *any* topic that
> has
> >> log compaction turned on.
> >>
> >> And, more specifically, if we want to make use of __consumer_offsets,
> then
> >> we cannot use compressed messages in any topic that has compaction
> turned
> >> on.
> >>
> >> Is that right?
> >> -James
> >>
> >>> -Todd
> >>>
> >>>
> >>> On Fri, Sep 18, 2015 at 9:54 AM, John Holland <
> >>> john.holland@objectpartners.com <javascript:;>> wrote:
> >>>
> >>>> Thanks!
> >>>>
> >>>> I did what you suggested and it worked except it was necessary for me
> to
> >>>> remove the cleaner-offset-checkpoint file from the data directory and
> >>>> restart the servers.  The log indicates all is well.
> >>>>
> >>>> Do you know what version the fix to this will be in? I'm not looking
> >>>> forward to dealing with this on a reoccurring basis.
> >>>>
> >>>> -John
> >>>>
> >>>> On Fri, Sep 18, 2015 at 8:48 AM Todd Palino <tpalino@gmail.com
> <javascript:;>> wrote:
> >>>>
> >>>>> Yes, this is a known concern, and it should be fixed with recent
> >> commits.
> >>>>> In the meantime, you'll have to do a little manual cleanup.
> >>>>>
> >>>>> The problem you're running into is a corrupt message in the offsets
> >>>> topic.
> >>>>> We've seen this a lot. What you need to do is set the topic
> >> configuration
> >>>>> to remove the cleanup.policy config, and set retention.ms and
> >> segment.ms
> >>>>> to
> >>>>> something reasonably low. I suggest using a value of 3 or 4 times
> your
> >>>>> commit interval for consumers. Then wait until the log segments
are
> >>>> reaped
> >>>>> (wait twice as long as the retention.ms you chose, to be safe).
Once
> >>>> this
> >>>>> is done, you can set the topic configuration back the way it was
> >> (remove
> >>>>> segment.ms and retention.ms configs, and set
> cleanup.policy=compact).
> >>>>> Lastly, you'll need to do a rolling bounce of the cluster to restart
> >> the
> >>>>> brokers (which restarts the log cleaner threads). Technically, you
> only
> >>>>> need to restart brokers where the threads have died, but it's easier
> to
> >>>>> just restart all of them.
> >>>>>
> >>>>> Keep in mind that when you do this, you are deleting old offsets.
If
> >> your
> >>>>> consumers are all live and healthy, this shouldn't be a problem
> because
> >>>>> they will just continue to commit their offsets properly. But if
you
> >> have
> >>>>> an offline consumer, you'll lose the committed offsets by doing
this.
> >>>>>
> >>>>> -Todd
> >>>>>
> >>>>>
> >>>>> On Fri, Sep 18, 2015 at 5:31 AM, John Holland <
> >>>>> john.holland@objectpartners.com <javascript:;>> wrote:
> >>>>>
> >>>>>> I've been experiencing this issue across several of our environments
> >>>> ever
> >>>>>> since we enabled the log cleaner for the __consumer_offsets
topic.
> >>>>>>
> >>>>>> We are on version 0.8.2.1 of kafka, using the new producer.
 All of
> >> our
> >>>>>> consumers are set to commit to kafka only.
> >>>>>>
> >>>>>> Below is the stack trace in the log I've encountered across
several
> >>>>>> different clusters.  A simple restart of kafka will allow compaction
> >> to
> >>>>>> continue on all of the other partitions but the incorrect one
will
> >>>> always
> >>>>>> fail.
> >>>>>>
> >>>>>> Here are the values for it from the kafka-topics --describe
command:
> >>>>>>
> >>>>>> Topic:__consumer_offsets PartitionCount:50 ReplicationFactor:3
> >>>>>> Configs:segment.bytes=104857600,cleanup.policy=compact
> >>>>>>
> >>>>>> Are there any recommendations on how to prevent this and the
best
> way
> >>>> to
> >>>>>> recover from this exception?  This is causing disk space to
fill up
> >>>>> quickly
> >>>>>> on the node.
> >>>>>>
> >>>>>> I did see an open issue that seems very similar to this
> >>>>>> https://issues.apache.org/jira/browse/KAFKA-1641 but this is
the
> >>>>>> __consumer_offsets topic which I have not had any part in setting
up
> >>>> nor
> >>>>>> producing to.
> >>>>>>
> >>>>>> [2015-09-18 02:57:25,520] INFO Cleaner 0: Beginning cleaning
of log
> >>>>>> __consumer_offsets-17. (kafka.log.LogCleaner)
> >>>>>> [2015-09-18 02:57:25,520] INFO Cleaner 0: Building offset map
for
> >>>>>> __consumer_offsets-17... (kafka.log.LogCleaner)
> >>>>>> [2015-09-18 02:57:25,609] INFO Cleaner 0: Building offset map
for
> log
> >>>>>> __consumer_offsets-17 for 46 segments in offset range [468079184,
> >>>>>> 528707475). (kafka.log.LogCleaner)
> >>>>>> [2015-09-18 02:57:25,645] ERROR [kafka-log-cleaner-thread-0],
Error
> >> due
> >>>>> to
> >>>>>> (kafka.log.LogCleaner)
> >>>>>> java.lang.IllegalArgumentException: requirement failed: Last
clean
> >>>> offset
> >>>>>> is 468079184 but segment base offset is 0 for log
> >>>> __consumer_offsets-17.
> >>>>>>       at scala.Predef$.require(Predef.scala:233)
> >>>>>>       at kafka.log.Cleaner.buildOffsetMap(LogCleaner.scala:509)
> >>>>>>       at kafka.log.Cleaner.clean(LogCleaner.scala:307)
> >>>>>>       at
> >>>>>>
> kafka.log.LogCleaner$CleanerThread.cleanOrSleep(LogCleaner.scala:221)
> >>>>>>       at
> >>>>> kafka.log.LogCleaner$CleanerThread.doWork(LogCleaner.scala:199)
> >>>>>>       at
> >>>>> kafka.utils.ShutdownableThread.run(ShutdownableThread.scala:60)
> >>>>>> [2015-09-18 02:57:25,654] INFO [kafka-log-cleaner-thread-0],
Stopped
> >>>>>> (kafka.log.LogCleaner)
> >>>>>>
> >>>>>> -John
> >>>>>>
> >>>>>
> >>>>
> >>
> >>
>
>
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