[KAFKA-8629] Kafka Streams Apps to support small native images through GraalVM

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 2.3.0
• Component/s: streams
• Environment: OSX ; Linux on Docker
• Assignee: Andy Muir
• Reporter: Andy Muir
• Created: 04/Jul/19 06:41
• Updated: 14/Feb/21 16:22

Description

I'm investigating using GraalVM to help with reducing docker image size and required resources for a simple Kafka Streams microservice. To this end, I'm looking at running a microservice which:
1) consumes from a Kafka topic (XML)
2) Transforms into JSON
3) Produces to a new Kafka topic.

The Kafka Streams app running in the JVM works fine.

When I attempt to build it to a GraalVM native image (binary executable which does not require the JVM, hence smaller image size and less resources), I encountered a few incompatibilities with the source code in Kafka.

I've implemented a workaround for each of these in a fork (link to follow) to help establish if it is feasible. I don't intend (at this stage) for the changes to be applied to the broker - I'm only after Kafka Streams for now. I'm not sure whether it'd be a good idea for the broker itself to run as a native image!

There were 2 issues getting the native image with kafka streams:
1) Some Reflection use cases using MethodHandle
2) Anything JMX

To work around these issues, I have:
1) Replaced use of MethodHandle with alternatives
2) Commented out the JMX code in a few places

While the first may be sustainable, I'd expect that the 2nd option should be put behind a configuration switch to allow the existing code to be used by default and turning off JMX if configured.

I haven't created a PR for now, as I'd like feedback to decide if it is going to be feasible to carry this forwards.