How do I change RF using Kafka manager
I think it's possible to increase the replication for a topic after creation
https://cwiki.apache.org/confluence/display/KAFKA/Replication+tools
https://kafka.apache.org/081/ops.html
Increasing the replication factor of an existing partition is easy. Just specify the extra replicas in the custom reassignment json file and use it with the --execute option to increase the replication factor of the specified partitions.
There is a tool called kafkat. helped me figure out some problem with my kafka configuration. It allows for changes to RF after topic creation using scripts provided by kafka itself.
Running the following will make the changes, as well as giving you the old assignment json incase you need to rollback.
./kafka-reassign-partitions.sh --zookeeper 127.0.0.1 --reassignment-json-file /tmp/increase-rf.json --execute