Kafka

Configuration Options

Required Options

bootstrap_servers(required)

A comma-separated list of host and port pairs that are the addresses of the Kafka brokers in a "bootstrap" Kafka cluster that a Kafka client connects to initially to bootstrap itself.

Type	Syntax	Default	Example
string	literal		["10.14.22.123:9092,10.14.23.332:9092"]

inputs(required)

A list of upstream source or transform IDs. Wildcards (*) are supported.

See configuration for more info.

Type	Syntax	Default	Example
array	literal		["my-source-or-transform-id","prefix-*"]

encoding(required)

Configures the encoding specific sink behavior.

Type	Syntax	Default	Example
hash	literal		[]

topic(required)

The Kafka topic name to write events to.

Type	Syntax	Default	Example
string	literal		["topic-1234","logs-{{unit}}-%Y-%m-%d"]

type(required)

The component type. This is a required field for all components and tells Vector which component to use.

Type	Syntax	Default	Example
string	literal		["kafka"]

Advanced Options

key_field(optional)

The log field name or tags key to use for the topic key. If the field does not exist in the log or in tags, a blank value will be used. If unspecified, the key is not sent. Kafka uses a hash of the key to choose the partition or uses round-robin if the record has no key.

Type	Syntax	Default	Example
string	literal		["user_id"]

librdkafka_options(optional)

Advanced options. See librdkafka documentation for details.

Type	Syntax	Default	Example
hash			[{"client.id":"${ENV_VAR}","fetch.error.backoff.ms":"1000","socket.send.buffer.bytes":"100"}]

message_timeout_ms(optional)

Local message timeout.

Type	Syntax	Default	Example
uint		300000	[150000,450000]

sasl(optional)

Options for SASL/SCRAM authentication support.

Type	Syntax	Default	Example
hash	literal		[]

socket_timeout_ms(optional)

Default timeout for network requests.

Type	Syntax	Default	Example
uint		60000	[30000,60000]

buffer(optional)

Configures the sink specific buffer behavior.

Type	Syntax	Default	Example
hash	literal		[]

batch(optional)

Configures the sink batching behavior.

Type	Syntax	Default	Example
hash			[]

compression(optional)

The compression strategy used to compress the encoded event data before transmission.

Some cloud storage API clients and browsers will handle decompression transparently, so files may not always appear to be compressed depending how they are accessed.

Type	Syntax	Default	Example
string	literal	none

healthcheck(optional)

Health check options for the sink.

Type	Syntax	Default	Example
hash			[]

tls(optional)

Configures the TLS options for incoming connections.

Type	Syntax	Default	Example
hash	literal		[]

How it Works

librdkafka

The kafka sink uses librdkafka under the hood. This is a battle-tested, high performance, and reliable library that facilitates communication with Kafka. As Vector produces static MUSL builds, this dependency is packaged with Vector, meaning you do not need to install it.

State

This component is stateless, meaning its behavior is consistent across each input.

Health checks

Health checks ensure that the downstream service is accessible and ready to accept data. This check is performed upon sink initialization. If the health check fails an error will be logged and Vector will proceed to start.

Transport Layer Security (TLS)

Vector uses OpenSSL for TLS protocols due to OpenSSL's maturity. You can enable and adjust TLS behavior using the tls.* options.

Buffers and batches

This component buffers & batches data as shown in the diagram above. You'll notice that Vector treats these concepts differently, instead of treating them as global concepts, Vector treats them as sink specific concepts. This isolates sinks, ensuring services disruptions are contained and delivery guarantees are honored.

Batches are flushed when 1 of 2 conditions are met:

The batch age meets or exceeds the configured timeout_secs.
The batch size meets or exceeds the configured max_size or max_events.

Buffers are controlled via the buffer.* options.