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Another limitation is that RJR does not provide access to the JobResult of a completed job, so we may need to return the UNKNOWN result, when we failover in application mode (FLINK-21928). Having access to a JobResult, after the job has completed, would also pave the road for supporting multi-stage jobs in ApplicationMode and highly available job drivers in general.

Public Interfaces

Briefly list any new interfaces that will be introduced as part of this proposal or any existing interfaces that will be removed or changed. The purpose of this section is to concisely call out the public contract that will come along with this feature.

A public interface is any change to the following:

• RunningJobsRegistry will be replaced by JobResultStore
• k8s- and ZK-specific implementations of RunningJobsRegistry will be replaced by a file-based approach
  • Users that use a customized HA implementation might be affected by this change because the HAServices interface is going to be modified
• New configuration parameters are going to be introduced to make the file-based JobResultStore implementation configurable
• REST API for the JobResult might be extended to also include the cleanup state of this Job

• Binary log format

• The network protocol and api behavior

• Any class in the public packages under clientsConfiguration, especially client configuration

  • org/apache/kafka/common/serialization

  • org/apache/kafka/common

  • org/apache/kafka/common/errors

  • org/apache/kafka/clients/producer

  • org/apache/kafka/clients/consumer (eventually, once stable)

• Monitoring

• Command line tools and arguments

• Anything else that will likely break existing users in some way when they upgrade

Proposed Changes

In this document we propose removing RJR and introducing a new opt-in component, the JobResultStore (JSR).

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