jelmerk/flink-cancel-restart-job-without-checkpointing

Java

Steps to reproduce

Bring up zookeeper, kafka and flink
```
docker-compose up -d
```
Build the job
```
mvn clean package
```

Deploy the job

docker exec -i -t flink /opt/flink/bin/flink run -q -d /app/flink-app-1.0.jar

View the flink console output
```
docker-compose logs -f -t flink
```
Send some messages to the kafka topic

Leave the console output running then in another terminal start the console producer
```
docker exec -i -t kafka /opt/kafka/bin/kafka-console-producer.sh --topic mytopic --broker-list kafka:9092
```
Enter the following lines of text
```
message 1
message 2
```
If you look at your other terminal these messages should be in the console output
Save the state of the job

Open yet another terminal and execute
```
docker exec -i -t flink /opt/flink/bin/flink list
```
to find out the job id.

and then cancel the job with a savepoint
```
docker exec -i -t flink /opt/flink/bin/flink cancel -s <job id>
```
The output wil indicate where the savepoint has been created

redeploy the job from a savepoint

docker exec -i -t flink /opt/flink/bin/flink run -q -d -s <savepoint> /app/flink-app-1.0.jar

Send more messages and make the job blow up and restart itself

Switch back to the terminal that runs the kafka console producer and enter the following lines of text
```
message 3
message 4
message 5
implode
```

The implode message will make the flink job throw an exception and restart itself but it will start processing messages from the save point!

Because this app does not do checkpointing when the savepoint was created might be a long long long time ago by the time an exception occurs