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Posted to users@kafka.apache.org by Sven Ludwig <s_...@gmx.de> on 2016/12/12 12:57:32 UTC

RE: ActiveControllerCount is always will be either 0 or 1 in 3 nodes kafka cluster?

Hi,
 
in JMX each Kafka broker has a value 1 or 0 for ActiveControllerCount. As I understood from this thread, the sum of these values across the cluster should never be something other than 1. The documentation at http://docs.confluent.io/3.1.0/kafka/monitoring.html should be improved to make that clear. Currently it is misleading:

kafka.controller:type=KafkaController,name=ActiveControllerCount
Number of active controllers in the cluster. Alert if value is anything other than 1.

Suggested:

kafka.controller:type=KafkaController,name=ActiveControllerCount
Number of active controllers on a broker. Alert if the aggregated sum across all brokers in the cluster is anything other than 1, because in a cluster there should only be one broker with an active controller (cluster singleton).

Kind Regards,
Sven

Re: ActiveControllerCount is always will be either 0 or 1 in 3 nodes kafka cluster?

Posted by Tom Crayford <tc...@heroku.com>.
This is confluent documentation, not Apache documentation. I'd recommend
talking to Confluent about that.

On Mon, Dec 12, 2016 at 4:57 AM, Sven Ludwig <s_...@gmx.de> wrote:

> Hi,
>
> in JMX each Kafka broker has a value 1 or 0 for ActiveControllerCount. As
> I understood from this thread, the sum of these values across the cluster
> should never be something other than 1. The documentation at
> http://docs.confluent.io/3.1.0/kafka/monitoring.html should be improved
> to make that clear. Currently it is misleading:
>
> kafka.controller:type=KafkaController,name=ActiveControllerCount
> Number of active controllers in the cluster. Alert if value is anything
> other than 1.
>
> Suggested:
>
> kafka.controller:type=KafkaController,name=ActiveControllerCount
> Number of active controllers on a broker. Alert if the aggregated sum
> across all brokers in the cluster is anything other than 1, because in a
> cluster there should only be one broker with an active controller (cluster
> singleton).
>
> Kind Regards,
> Sven
>

Re: ActiveControllerCount is always will be either 0 or 1 in 3 nodes kafka cluster?

Posted by Apurva Mehta <ap...@confluent.io>.
Thanks Sven, I will followup and ensure that the document is tightened up.

Apurva

On Mon, Dec 12, 2016 at 4:57 AM, Sven Ludwig <s_...@gmx.de> wrote:

> Hi,
>
> in JMX each Kafka broker has a value 1 or 0 for ActiveControllerCount. As
> I understood from this thread, the sum of these values across the cluster
> should never be something other than 1. The documentation at
> http://docs.confluent.io/3.1.0/kafka/monitoring.html should be improved
> to make that clear. Currently it is misleading:
>
> kafka.controller:type=KafkaController,name=ActiveControllerCount
> Number of active controllers in the cluster. Alert if value is anything
> other than 1.
>
> Suggested:
>
> kafka.controller:type=KafkaController,name=ActiveControllerCount
> Number of active controllers on a broker. Alert if the aggregated sum
> across all brokers in the cluster is anything other than 1, because in a
> cluster there should only be one broker with an active controller (cluster
> singleton).
>
> Kind Regards,
> Sven
>