Hi Mike,
What Kafka version are you using? I tried the latest trunk (0.7) and the
attributes I see are:
Broker/partition,fetch offset,consumer offset
The values seem to be correct - and if you want to get the latest available
offset/consumer lag there are mbean operations (not attributes) that also
seem to work correctly.
On Wed, Nov 21, 2012 at 7:57 AM, Mike Heffner <m...@librato.com> wrote:
> Well, I've currently "solved" the monitoring problem on our end by skipping
> the JMX attributes and using the 'kafka-rb' Ruby gem to read the latest
> offset for the topic. This is the comparison of offsets read from the
> consumer, JMX, and the Ruby gem:
>
> Storm Consumer offset:
> ---------------------------------
> "offset"=>2847272176, "partition"=>2, "broker"=>{"host"=>"10.120.x.x",
> "port"=>9092}, "topic"=>"mcommits"}
>
> JMX Attributes:
> ---------------------
> attrs: {"CurrentOffset"=>162919578, "Name"=>"mcommits-2",
> "NumAppendedMessages"=>7285958, "NumberOfSegments"=>3, "Size"=>1236661577}
>
> OFFSETS command sent from Ruby gem:
> ------------------------------------------------------------
> 10.120.x.x:mcommits:2: latest offset: 2847274728
>
> This is the output of the log file directory for this topic:partition:
>
> -rw-r--r-- 1 root root 536871010 2012-11-16 05:36
> 00000000001610613151.kafka
> -rw-r--r-- 1 root root 536870989 2012-11-20 14:28
> 00000000002147484161.kafka
> -rw-r--r-- 1 root root 162919578 2012-11-21 15:48
> 00000000002684355150.kafka
>
> So, the "latest offset" from the Ruby gem matches what I would expect to
> see -- only slightly ahead of the active consumer. AFAICT, the values from
> JMX aren't usable to monitor this. Should I file a bug or feature request
> to publish an offset in the JMX attributes that matches the 'latest offset'
> read from the Kakfa server?
>
> Cheers,
>
> Mike
>
>
> On Wed, Nov 21, 2012 at 12:08 AM, Jun Rao <jun...@gmail.com> wrote:
>
> > The attribute getCurrentOffset gives the log end offset. It's not
> > necessarily the log size though since older segments could be deleted.
> >
> > Thanks,
> >
> > Jun
> >
> > On Tue, Nov 20, 2012 at 1:12 PM, Mike Heffner <m...@librato.com> wrote:
> >
> > > Jun,
> > >
> > > Do you have any idea on what the JMX attribute values on the beans "
> > > kafka:type=kafka.logs.{topic name}-{partition idx}" represent then? It
> > > seems like these should correctly represent the current offsets of the
> > > producer logs? They appeared to track correctly for a while, but once
> the
> > > log size grew, they seemed to no longer be correct. Is there
> potentially
> > a
> > > bug in these values are large log sizes?
> > >
> > > I can try the other interface, but it would be nice to know what's
> wrong
> > > with the current JMX values.
> > >
> > > Thanks,
> > >
> > > Mike
> > >
> > >
> > > On Tue, Nov 20, 2012 at 12:12 PM, Jun Rao <jun...@gmail.com> wrote:
> > >
> > > > The tool gets the end offset of the log using getOffsetBefore and the
> > > > consumer offset from ZK. It then calculates the lag.
> > > >
> > > > We do have a JMX for lag in ZookeeperConsumerConnector. The api is
> the
> > > > following, but you need to provide topic/brokerid/partitionid.
> > > >
> > > > /**
> > > > * JMX interface for monitoring consumer
> > > > */
> > > > trait ZookeeperConsumerConnectorMBean {
> > > > def getPartOwnerStats: String
> > > > def getConsumerGroup: String
> > > > def getOffsetLag(topic: String, brokerId: Int, partitionId: Int):
> > Long
> > > > def getConsumedOffset(topic: String, brokerId: Int, partitionId:
> > Int):
> > > > Long
> > > > def getLatestOffset(topic: String, brokerId: Int, partitionId:
> Int):
> > > Long
> > > > }
> > > >
> > > > Thanks
> > > >
> > > > Jun
> > > >
> > > > On Tue, Nov 20, 2012 at 8:03 AM, Mike Heffner <m...@librato.com>
> > wrote:
> > > >
> > > > > I have not tried that yet, I was hoping to use an existing Ruby
> > > > monitoring
> > > > > process that we use to monitor several other existing resources. I
> > > also
> > > > > don't want to make changes to the Kafka consumer code, as it's part
> > of
> > > a
> > > > > bundled package (Storm).
> > > > >
> > > > > Where does ConsumerOffsetChecker pull its information from?
> Shouldn't
> > > the
> > > > > values from JMX match? Guess I might need to look at its source
> code
> > to
> > > > > figure out what it's doing.
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > On Tue, Nov 20, 2012 at 12:34 AM, Jun Rao <jun...@gmail.com>
> wrote:
> > > > >
> > > > > > Instead of using jmx, have you tried using ConsumerOffsetChecker
> to
> > > > > figure
> > > > > > out the consumer lag?
> > > > > >
> > > > > > Thanks,
> > > > > >
> > > > > > Jun
> > > > > >
> > > > > > On Mon, Nov 19, 2012 at 7:10 PM, Mike Heffner <m...@librato.com>
> > > > wrote:
> > > > > >
> > > > > > > Hi,
> > > > > > >
> > > > > > > I am trying to write a custom monitoring script for our Kafka
> > setup
> > > > and
> > > > > > > would like some help understanding how to interpret the JMX
> > > > attributes.
> > > > > > >
> > > > > > > In our setup, the consumers are writing their current offset
> to a
> > > > path
> > > > > in
> > > > > > > ZK. This is the value they are getting back from a call
> > > > > > > to SimpleConsumer.getOffsetsBefore(). A snapshot of this value
> > > looks
> > > > > > like:
> > > > > > >
> > > > > > > {"offset"=>5338008447, "partition"=>2,
> > > > "broker"=>{"host"=>"10.x.x.94",
> > > > > > > "port"=>9092}, "topic"=>"mcommits"}
> > > > > > >
> > > > > > > Using the MX4J interface, I poll the
> > > > > > > bean "kafka:type=kafka.logs.mcommits-2" on host 10.x.x.94 and
> get
> > > the
> > > > > > > attribute values:
> > > > > > >
> > > > > > > {"CurrentOffset"=>506171524, "Name"=>"mcommits-2",
> > > > > > > "NumAppendedMessages"=>10526508, "NumberOfSegments"=>4,
> > > > > > "Size"=>2116784530}
> > > > > > >
> > > > > > > At the time both of these values were snapshotted, this
> consumer
> > > was
> > > > > > close
> > > > > > > to the end of the log file. In that case, I would expect both
> > > offsets
> > > > > to
> > > > > > be
> > > > > > > fairly similar, however the consumer offset is >> the producer
> > log
> > > > > > offset,
> > > > > > > which doesn't make sense.
> > > > > > >
> > > > > > > Clearly there is something I'm not understanding. How do I use
> > the
> > > > JMX
> > > > > > > attributes to calculate how far behind the consumer is from the
> > end
> > > > of
> > > > > > the
> > > > > > > log file? In this scenario the consumer offset is >> both the
> > > > > > CurrentOffset
> > > > > > > value and the Size value. Is there a way of interpreting these
> > > values
> > > > > > that
> > > > > > > I'm not seeing?
> > > > > > >
> > > > > > >
> > > > > > > Thanks,
> > > > > > >
> > > > > > > Mike
> > > > > > >
> > > > > > > --
> > > > > > >
> > > > > > > Mike Heffner <m...@librato.com>
> > > > > > > Librato, Inc.
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > >
> > > > > Mike Heffner <m...@librato.com>
> > > > > Librato, Inc.
> > > > >
> > > >
> > >
> > >
> > >
> > > --
> > >
> > > Mike Heffner <m...@librato.com>
> > > Librato, Inc.
> > >
> >
>
>
>
> --
>
> Mike Heffner <m...@librato.com>
> Librato, Inc.
>
