Kubernetes Example

Background

This example demonstrates deploying Apache Flink StateFun, together with a single remote function to kubernetes.

All the components are already pre-configured and contains all the resource definitions ready to be applied with kubectl. All the resources are deployed to a dedicated namespace - statefun.

What's inside?

The following components will be installed:

1. Apache Kafka
2. MinIO (S3 compatible object store)
3. A StateFun service functions.py
4. Apache Flink Cluster that executes a StateFun Job. Take a look at module.yaml config-map. The resources defined at [statefun-runtime.yaml](04-statefun/ 01-statefun-runtime.yaml) are already pre-configured for that specific example.

Prerequisites

minikube config set memory 5120
minikube start
minikube ssh 'sudo ip link set docker0 promisc on'
eval $(minikube -p minikube docker-env)

Create the statefun namespace.

kubectl create -f 00-namespace
kubectl config set-context --current --namespace statefun

Create auxiliary services that are need for this example:

kubectl create -f 01-minio
kubectl create -f 02-kafka

Create the function:

NOTE: please make sure that you've run eval $(minikube -p minikube docker-env) In your current terminal session.

cd 03-functions
make image
make service
cd ..

Start the StateFun runtime

kubectl create -f 04-statefun

Open the Flink's WEB UI

 kubectl port-forward svc/statefun-master-rest 8081:8081 -n statefun

Now you can explore Apache Flink's WEB interface:

http://localhost:8081/#/overview

Interact with the Function!

In one terminal run:

bin/show-function-logs.sh

And in another run:

bin/invoke-function.sh

When prompted with:

Please enter a target id:

try writing your name.

Please enter a message:

Write any message you would like.

In the previous console you will see: Hello from <name>: you wrote <message>!

Teardown

kubectl delete namespace statefun
minikube stop