KIP-345 introduced static membership.
In future works section it’s discussed the convenience of adding a new tool to remove instances from the group. Static membership doesn’t remove a member from the group until session timeout expires (usually a long time).
It’s been a while since static membership is around but that tool never made it.
We miss it so many times that we set up a quick solution.
Help option will show you
This tool helps to quickly remove instances from a running Kafka Streams app.
Option (* = required) Description
--------------------- -----------
* --application-id <String: id> The Kafka Streams application ID
(application.id).
--bootstrap-servers <String: urls> Comma-separated list of broker urls with
format: HOST1:PORT1,HOST2:PORT2 (default:
localhost:9092)
--config-file <String: file name> Property file containing configs to be
passed to admin clients and embedded
consumer.
--execute <Boolean: execute> Set this flag to true to execute remove
command. Otherwise just will inform you
of the result. (default: false)
--help Print usage information.
--instance-ids <String: list> Comma-separated list of instance ids. The
tool will remove this instances from the
list of members of the consumer group.
--prefix-keep <String: prefix> Remove all instances whose id doesn't match
this prefix
--version Print version information and exit.
Unless you set execute parameter to true, it wouldn’t do anything.
Both instance-ids and prefix-keep let you set up the instances to remove.
Running the tool without setting up a set of instances to remove will show you current instances.