Group coordinator in 0.9

[Oleksiy Krivoshey <ol...@gmail.com>]

Hi!

Is it possible for the group coordinator for the same group to change from
one host to some other during cluster runtime? For example when the host
that used to be the coordinator is down - can Kafka cluster choose new
coordinator for the group? Or is it fixed?

Thanks!

Re: Group coordinator in 0.9

[Stevo Slavić <ss...@gmail.com>]

Hello Oleksiy,

All offsets for given consumer group are stored in (and fetched from) one
and only one partition of all partitions of __consumer_offsets topic. By
default __consumer_offsets has 50 partitions and for each of these
partitions replication factor is 3, so there is one lead and 2 extra
replicas.

If I'm not mistaken, offset/group coordinator for a given consumer group
lives on a broker in Kafka cluster which is lead for __consumer_offsets
topic partition used for offsets of that consumer group.

So your question is I guess equivalent to question - can a different broker
become a lead for a partition, for which answer is yes, as long as there
are alive replicas for that partition.

Kind regards,
Stevo Slavic.

On Sat, Jan 9, 2016 at 4:23 PM, Oleksiy Krivoshey <ol...@gmail.com>
wrote:

> Hi!
>
> Is it possible for the group coordinator for the same group to change from
> one host to some other during cluster runtime? For example when the host
> that used to be the coordinator is down - can Kafka cluster choose new
> coordinator for the group? Or is it fixed?
>
> Thanks!
>