Broker Metrics

These metrics are emitted by korvet-broker.

Metrics

Backpressure Connections

Current number of broker connections with backpressure applied.

Name: korvet.broker.backpressure.connections
Type: gauge

Backpressure Transitions

Backpressure lifecycle transitions, tagged by action=applied|released.

Name: korvet.broker.backpressure.transitions
Type: counter

Table 1. Tags
Key	Description
`action`	Backpressure action: `applied` or `released`.

Connections

Current number of active broker connections.

Name: korvet.broker.connections
Type: gauge

Failures

Number of broker failures, including lifecycle (start) and authentication failures (tagged operation=auth).

Name: korvet.broker.failures
Type: counter

Table 2. Tags
Key	Description
`error_type`	Failure category, lower-cased.
`operation`	Logical operation name.

Fetch Latency

Fetch request latency.

Name: korvet.broker.fetch
Type: timer
Base unit: seconds

Table 3. Tags
Key	Description
`topic`	Kafka topic name.

Frame Size

Broker Kafka frame size in bytes, by direction (request/response) and API key.

Name: korvet.broker.frame_size
Type: distribution summary
Base unit: bytes

Table 4. Tags
Key	Description
`api_key`	Kafka API key (request type) on the broker, lower-cased.
`direction`	Frame direction: `request` or `response`.

Log Start Offset

Log start offset per (topic, partition): earliest still-readable offset. Empty partitions report 0.

Name: korvet.broker.log_start_offset
Type: gauge

Table 5. Tags
Key	Description
`partition`	Kafka partition number, as a decimal string.
`topic`	Kafka topic name.

Lossy Records

Number of records affected by lossy offset mapping, by phase.

Name: korvet.broker.lossy_records
Type: counter

Table 6. Tags
Key	Description
`phase`	Lifecycle phase, lower-cased.
`topic`	Kafka topic name.

Max Offset

High watermark per (topic, partition): next offset to be assigned (i.e. latest visible offset + 1). Empty partitions report 0.

Name: korvet.broker.max_offset
Type: gauge

Table 7. Tags
Key	Description
`partition`	Kafka partition number, as a decimal string.
`topic`	Kafka topic name.

Pending

Current broker request bytes waiting on asynchronous completion.

Name: korvet.broker.pending
Type: gauge
Base unit: bytes

Produce Latency

Produce request latency.

Name: korvet.broker.produce
Type: timer
Base unit: seconds

Table 8. Tags
Key	Description
`topic`	Kafka topic name.

Produce Records

Number of records successfully produced.

Name: korvet.broker.produce.records
Type: counter
Base unit: records

Table 9. Tags
Key	Description
`topic`	Kafka topic name.

Rebalances

Number of consumer group rebalance lifecycle events.

Name: korvet.broker.rebalances
Type: counter

Table 10. Tags
Key	Description
`phase`	Lifecycle phase, lower-cased.

Request Latency

Broker Kafka API request latency, observed per request.

Name: korvet.broker.request
Type: timer
Base unit: seconds

Table 11. Tags
Key	Description
`api_key`	Kafka API key (request type) on the broker, lower-cased.
`result`	Outcome of the broker request, lower-cased.

Up

Whether the broker is currently running.

Name: korvet.broker.up
Type: gauge