THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
Status
Current state: Under Discussion
Discussion thread: here
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. Although producers and consumers used in Kafka Connect can be monitored, the Kafka Connect framework only has a few metrics capturing the number of connectors and tasks for each worker. To augment these existing metrics, we propose to add metrics to monitor more information about the connectors, tasks, and workers. All metrics reported by each worker are scoped by the activities within that worker.
There are several things that are out of scope for this proposal, though they may be addressed in future KIPs. First, this proposal expressly avoids changes to the Connect API, and therefore does not address how connector implementations can define their own connector-specific metrics. Second, Kafka Connect does not have any existing mechanism to aggregate the metrics reported by each worker.
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. The context of all metrics are limited to the worker where the metrics are being reported, and all metrics include the worker ID in the MBean attribute (similarly to how Kafka producer and consumer metrics include the client ID).
Connector Metrics
| Metric Name | Description | MBean attribute |
|---|---|---|
| connector-type | The type of the connector, one of: source, sink | kafka.connect:type=connector-metrics,name=connector-type,connector=([-.\w]+) |
| connector-class | The name of the connector class | kafka.connect:type=connector-metrics,name=connector-class,connector=([-.\w]+) |
| connector-version | The version of the connector class, as reported by the connector in this worker | kafka.connect:type=connector-metrics,name=connector-version,connector=([-.\w]+) |
| status | The current status of the connector in this worker, one of: running, paused, stopped | kafka.connect:type=connector-metrics,name=status,connector=([-.\w]+) |
Common Task Metrics
| Metric Name | Description | MBean attribute |
|---|---|---|
| status | The current status of this task, one of: unassigned, running, paused, failed, destroyed | kafka.connect:type=task-metrics,name=status,connector=([-.\w]+),task=([\d]+) |
| pause-ratio | The fraction of time this task has spent in the paused state. | kafka.connect:type=task-metrics,name=pause-ratio ,connector=([-.\w]+),task=([\d]+) |
| offset-commit-success-percentage | The average percentage of this task's offset commit attempts that succeeded | kafka.connect:type=task-metrics,name=offset-commit-success-percentage,connector=([-.\w]+),task=([\d]+) |
| offset-commit-failure-percentage | The average percentage of this task's offset commit attempts that failed or had an error | kafka.connect:type=task-metrics,name=offset-commit-failure-percentage,connector=([-.\w]+),task=([\d]+) |
| offset-commit-avg-time | The average time taken by this task to commit offsets | kafka.connect:type=task-metrics,name=offset-commit-max-time,connector=([-.\w]+),task=([\d]+) |
| offset-commit-max-time | The maximum time taken by this task to commit offsets | kafka.connect:type=task-metrics,name=offset-commit-max-time,connector=([-.\w]+),task=([\d]+) |
| batch-size-max | The maximum size of the batches processed by the connector | kafka.connect:type=task-metrics,name=batch-size-max,connector=([-.\w]+),task=([\d]+) |
| batch-size-avg | The average size of the batches processed by the connector | kafka.connect:type=task-metrics,name=batch-size-avg,connector=([-.\w]+),task=([\d]+) |
Source Task Metrics
| Metric Name | Description | MBean attribute |
|---|---|---|
| source-record-poll-rate | The average per-second number of records produced/polled (before transformation) by this task belonging to the named source connector in this worker. This is before transformations are applied. | kafka.connect:type=source-task-metrics,name=source-record-produce-rate,connector=([-.\w]+),task=([\d]+) |
| source-record-write-rate | The average per-second number of records per second output from the transformations and written to Kafka for this task belonging to the named source connector in this worker. This is after transformations are applied. | kafka.connect:type=source-task-metrics,name=source-record-write-rate,connector=([-.\w]+),task=([\d]+) |
Sink Task Metrics
| Metric Name | Description | MBean attribute |
|---|---|---|
| sink-record-read-rate | The average per-second number of records read from Kafka for this task belonging to the named sink connector in this worker. This is before transformations are applied. | kafka.connect:type=sink-task-metrics,name=sink-record-read-rate,connector=([-.\w]+),task=([\d]+) |
| sink-record-send-rate | The average per-second numbrer of records output from the transformations and sent to this task belonging to the named sink connector in this worker. This is after transformations are applied and excludes any records filtered out by the transformations. | kafka.connect:type=sink-task-metrics,name=sink-record-process-rate ,connector=([-.\w]+),task=([\d]+) |
| sink-record-lag-max | The maximum lag in terms of number of records for any partition in this window | kafka.connect:type=sink-task-metrics,name=sink-record-lag-max,connector=([-.\w]+),task=([\d]+) |
| sink-record-{topic}-{partition}.records-lag | The latest lag in terms of number of records behind the consumer the offset commits are for the topic partition. | kafka.connect:type=sink-task-metrics,name=sink-record-{topic}-{partition}-lag,connector=([-.\w]+),task=([\d]+) |
| sink-record-{topic}-{partition}.records-lag-avg | The average lag in terms of number of records behind the consumer the offset commits are for the topic partition. | kafka.connect:type=sink-task-metrics,name=sink-record-{topic}-{partition}-lag-avg,connector=([-.\w]+),task=([\d]+) |
| sink-record-{topic}-{partition}.records-lag-max | The maximum lag in terms of number of records behind the consumer the offset commits are for the topic partition. | kafka.connect:type=sink-task-metrics,name=sink-record-{topic}-{partition}-lag-max,connector=([-.\w]+),task=([\d]+) |
| partition-count | The number of topic partitions assigned to this task belonging to the named sink connector in this worker. | kafka.connect:type=sink-connector-metrics,name=partition-count,connector=([-.\w]+),task=([\d]+) |
Worker Metrics
| Metric Name | Description | MBean attribute |
|---|---|---|
assigned-tasks | The number of tasks run in this worker (existing metric) | kafka.connect:type=connect-coordinator-metrics,name=assigned-tasks |
| assigned-connectors | The number of connectors run in this worker (existing metric) | kafka.connect:type=connect-coordinator-metrics,name=assigned-connectors |
task-count | The number of tasks run in this worker | kafka.connect:type=connect-worker-metrics,name=task-count |
| connector-count | The number of connectors run in this worker | kafka.connect:type=connect-worker-metrics,name=connector-count |
| leader-name | The name of the group leader | kafka.connect:type=connect-worker-metrics,name=leader-name |
| state | The state of this worker, one of: rebalancing, running | kafka.connect:type=connect-worker-metrics,name=state |
Worker Rebalance Metrics
| Metric Name | Description | MBean attribute |
|---|---|---|
| rebalance-success-total | The total number of this worker's successful rebalances | kafka.connect:type=connect-worker-rebalance-metrics,name=rebalance-success-total |
| rebalance-success-percentage | The average percentage of this worker's rebalances that succeeded | kafka.connect:type=connect-worker-rebalance-metrics,name=rebalance-success-percentage |
| rebalance-failure-total | The total number of this worker's failed rebalances | kafka.connect:type=connect-worker-rebalance-metrics,name=rebalance-failure-total |
| rebalance-failure-percentage | The average percentage of this worker's rebalances that failed | kafka.connect:type=connect-worker-rebalance-metrics,name=rebalance-failure-percentage |
| rebalance-max-time | The maximum time spent by this worker to rebalance | kafka.connect:type=connect-worker-rebalance-metrics,name=rebalance-max-time |
| rebalance-99p-time | The 99th percentile time spent by this worker to rebalance during the last window (defaults to an hour) | kafka.connect:type=connect-worker-rebalance-metrics,name=rebalance-99p-time |
| rebalance-95p-time | The 95th percentile time spent by this worker to rebalance during the last window (defaults to an hour) | kafka.connect:type=connect-worker-rebalance-metrics,name=rebalance-95p-time |
| rebalance-90p-time | The 90th percentile time spent by this worker to rebalance during the last window (defaults to an hour) | kafka.connect:type=connect-worker-rebalance-metrics,name=rebalance-90p-time |
| rebalance-75p-time | The 75th percentile time spent by this worker to rebalance during the last window (defaults to an hour) | kafka.connect:type=connect-worker-rebalance-metrics,name=rebalance-75p-time |
| time-since-last-rebalance | The time since the most recent rebalance in this worker | kafka.connect:type=connect-worker-rebalance-metrics,name=time-since-last-rebalance |
| task-failure-rate | The number of tasks that failed in this worker | kafka.connect:type=connect-worker-rebalance-metrics,name=task-failure-rate |
Worker REST Metrics
| Metric Name | Description | MBean attribute |
|---|---|---|
| request-rate | The average per second number of requests handled by the REST endpoints in this worker | kafka.connect:type=worker-rest-metrics,name=request-rate |
Proposed Changes
We will add the relevant metrics as specified in the Public Interfaces section, except for the two existing metrics that will be left unmodified.
Compatibility, Deprecation, and Migration Plan
Two existing metrics exist but will not be changed.
Rejected Alternatives
None
The average per-second number of retried record sends for a topic.