Status

Current state: Under Discussion

Discussion thread: here [Change the link from the KIP proposal email archive to your own email thread]

JIRA: here

Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).

Motivation

An important part of deploying Kafka Connect is monitoring the health of the workers in a cluster and the connectors and tasks that have been deployed to the cluster. The Kafka Connect framework only has a few metrics capturing the number of connectors and tasks for each worker, so we propose to add metrics to monitor more information about the connectors, tasks, and workers. This proposal expressly avoids changes to the Connect API, and therefore does not address how connector implementations can define their own connector-specific metrics.

Public Interfaces

All of the following will be added via Kafka's metrics library like most of the metrics in the Kafka brokers and other components.

Connector Metrics

Number of records (meter)

Rebalance Metrics

• rebalance duration (max, avg)
• last rebalance time
• rebalance count

kafka.connect:type=connect-coordinator-metrics,name=assigned-connectors

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:

• 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

Describe the new thing you want to do in appropriate detail. This may be fairly extensive and have large subsections of its own. Or it may be a few sentences. Use judgement based on the scope of the change.

Compatibility, Deprecation, and Migration Plan

• What impact (if any) will there be on existing users?
• If we are changing behavior how will we phase out the older behavior?
• If we need special migration tools, describe them here.
• When will we remove the existing behavior?

Rejected Alternatives

If there are alternative ways of accomplishing the same thing, what were they? The purpose of this section is to motivate why the design is the way it is and not some other way.