Hey Chris,
I think you should be able to use the reassignment tool to add replicas.
You should be able to do something similar to migrate the partitions away
from the old brokers and onto the new ones and also increase the
replication factor at the same time. I tested just increasing the
replication factor with the following commands:
kafka % ./bin/kafka-topics.sh --bootstrap-server localhost:9092 --topic
__consumer_offsets --describe | grep 'Partition: 49'
Topic: __consumer_offsets Partition: 49 Leader: 1 Replicas: 1 Isr: 1
Offline:
kafka % cat reassignment.json
{
"version": 1,
"partitions": [
{
"topic": "__consumer_offsets",
"partition": 49,
"replicas": [ 1, 0 ]
}
]
}
kafka % ./bin/kafka-reassign-partitions.sh --bootstrap-server
localhost:9092 --reassignment-json-file reassignment.json --execute
Current partition replica assignment
{"version":1,"partitions":[{"topic":"__consumer_offsets","partition":49,"replicas":[1],"log_dirs":["any"]}]}
Save this to use as the --reassignment-json-file option during rollback
Successfully started partition reassignment for __consumer_offsets-49
kafka % ./bin/kafka-topics.sh --bootstrap-server localhost:9092 --topic
__consumer_offsets --describe | grep 'Partition: 49'
Topic: __consumer_offsets Partition: 49 Leader: 1 Replicas: 1,0 Isr: 1,0
Offline:
Andrew
On Fri, Dec 16, 2022 at 9:46 AM Chris Peart <ch...@peart.me.uk> wrote:
>
>
> Hi,
>
> We have a kafka production cluster that was setup with the defaults for
> __consumer_offsets & __transaction_state topics.
>
> Is there a way to increase the replication factor from 1 to 3 using the
> kafka-reassign-partitions tool?
>
> We are also replacing our 4 brokers with new brokers, this has been
> completed so we now have an 8 broker cluster and have migrated all the
> topics to the new brokers using the reassign tool except for the
> __consumer_offsets & __transaction_state topics.
>
> We stopped kafka on the old brokers today but all out consumers failed
> due to the __consumer_offsets & __transaction_state topics residing on
> the old brokers.
>
> I'm thinking we should could move the __consumer_offsets &
> __transaction_state topics to the now brokers using the reassign tool, i
> have done this on our dev platform and all is good. If you think this is
> good idea we can then can stop kafka on the old nodes and then work on
> the replication factoron the new nodes?
>
> The problem i have is how do we change the replication factor to 3 after
> we migrate the __consumer_offsets & __transaction_state topics?
>
> Thanks in advance.
>
> Chris
