Spring Batch: How to start a job but not execute it, but execute it in an other java instance - spring-batch

Question

I plan to use Spring Batch. We like to initiate new jobs executions in our pods that are answering the frontend requests.
Pseudo Code:
#PostMapping(path = "/request-report/{id}")
public void requestReport(String id){
this.jobOperator.start("reportJob", new Properties("1"));
}
But we don't want the job to be executed in the frontend pod. For that we like to build a separate micro service pod.
I see the following solutions:
do a rest call from the frontend pod to the spring-batch pod and start the job there. i could do this, but if possible, i like to skip that step and integrate it over the spring batch db.
in the frontend pod i create JobLauncher that has SimpleAsyncTaskExecutor with size zero. So it will never execute a job.
https://docs.spring.io/spring-batch/docs/current/reference/html/job.html#configuringJobLauncher
#Bean
public JobLauncher jobLauncher() {
SimpleJobLauncher jobLauncher = new SimpleJobLauncher();
jobLauncher.setJobRepository(jobRepository());
jobLauncher.setTaskExecutor(new SimpleAsyncTaskExecutor());
jobLauncher.afterPropertiesSet();
return jobLauncher;
}
in the front end pod, i do not use the BatchAutoConfiguration but leaf out some stuff, but what?
I think i also have to write some software that scans the job table and check if there is a not started job present, and start is again in the spring-batch-pod.
Thanks for you help!

Answer 1

If you configure your job launcher with a SimpleAsyncTaskExecutor, it will start jobs in separate threads in the same JVM (hence in the same container and pod).
So unless you provide a custom TaskExecutor that launches jobs in separate JVM/container/pod, you would need to change your architecture to use a job queue. The section Launching Batch Jobs through Messages from the reference docs shows how to setup such pattern.