redpanda

A Kafka output using the Franz Kafka client library.

Common

# Common config fields, showing default values
output:
  label: ""
  redpanda:
    seed_brokers: [] # No default (optional)
    topic: "" # No default (required)
    key: "" # No default (optional)
    partition: "" # No default (optional)
    metadata:
      include_prefixes: []
      include_patterns: []
    max_in_flight: 256
    batching:
      count: 0
      byte_size: 0
      period: ""
      check: ""

Advanced

# All config fields, showing default values
output:
  label: ""
  redpanda:
    seed_brokers: [] # No default (optional)
    client_id: "redpanda-connect"
    tls:
      enabled: false
      skip_cert_verify: false
      enable_renegotiation: false
      root_cas: ""
      root_cas_file: ""
      client_certs: []
    sasl: [] # No default (optional)
    metadata_max_age: "1m"
    request_timeout_overhead: "10s"
    conn_idle_timeout: "20s"
    tcp:
      connect_timeout: "0s"
      keep_alive:
        idle: "15s"
        interval: "15s"
        count: 9
      tcp_user_timeout: "0s"
    topic: "" # No default (required)
    key: "" # No default (optional)
    partition: "" # No default (optional)
    metadata:
      include_prefixes: []
      include_patterns: []
    timestamp_ms: "" # No default (optional)
    max_in_flight: 256
    batching:
      count: 0
      byte_size: 0
      period: ""
      check: ""
      processors: [] # No default (optional)
    inject_tracing_map: "" # No default (optional)
    partitioner: "" # No default (optional)
    idempotent_write: true
    acks: "all"
    compression: "" # No default (optional)
    allow_auto_topic_creation: true
    timeout: "10s"
    max_message_bytes: "1MiB"
    broker_write_max_bytes: "100MiB"
    max_buffered_records: 10000
    max_buffered_bytes: "0"
    max_in_flight_requests: 1
    record_retries: 0
    record_delivery_timeout: "0s"

Writes a batch of messages to Kafka brokers and waits for acknowledgement before propagating it back to the input.

Examples

Simple Common Output

Data is generated and written to a topic bar, targeting the cluster configured within the redpanda block at the bottom. This is useful as it allows us to configure TLS and SASL only once for potentially multiple inputs and outputs.

input:
  generate:
    interval: 1s
    mapping: 'root.name = fake("name")'

pipeline:
  processors:
    - mutation: |
        root.id = uuid_v4()
        root.loud_name = this.name.uppercase()

output:
  redpanda:
    topic: bar
    key: ${! @id }

redpanda:
  seed_brokers: [ "127.0.0.1:9092" ]
  tls:
    enabled: true
  sasl:
    - mechanism: SCRAM-SHA-512
      password: bar
      username: foo

Fields

seed_brokers

A list of broker addresses to connect to in order to establish connections. If an item of the list contains commas it will be expanded into multiple addresses. When this field is omitted the global redpanda block will be referenced for connection details.

Type: array of string

client_id

An identifier for the client connection.

Type: string
Default: "redpanda-connect"

tls

Custom TLS settings can be used to override system defaults.

Type: object

tls.enabled

Whether custom TLS settings are enabled.

Type: bool
Default: false

tls.skip_cert_verify

Whether to skip server side certificate verification.

Type: bool
Default: false

tls.enable_renegotiation

Whether to allow the remote server to repeatedly request renegotiation. Enable this option if you're seeing the error message local error: tls: no renegotiation.

Type: bool
Default: false

tls.root_cas

An optional root certificate authority to use. This is a string, representing a certificate chain from the parent trusted root certificate, to possible intermediate signing certificates, to the host certificate.

Secret

This field contains sensitive information. Use a secret reference rather than a literal value.

Type: string
Default: ""

tls.root_cas_file

An optional path of a root certificate authority file to use. This is a file, often with a .pem extension, containing a certificate chain from the parent trusted root certificate, to possible intermediate signing certificates, to the host certificate.

Type: string
Default: ""

tls.client_certs

A list of client certificates to use. For each certificate either the fields cert and key, or cert_file and key_file should be specified, but not both.

Type: array of object
Default: []

tls.client_certs[].cert

A plain text certificate to use.

Type: string
Default: ""

tls.client_certs[].key

A plain text certificate key to use.

Secret

This field contains sensitive information. Use a secret reference rather than a literal value.

Type: string
Default: ""

tls.client_certs[].cert_file

The path of a certificate to use.

Type: string
Default: ""

tls.client_certs[].key_file

The path of a certificate key to use.

Type: string
Default: ""

tls.client_certs[].password

A plain text password for when the private key is password encrypted in PKCS#1 or PKCS#8 format. The obsolete pbeWithMD5AndDES-CBC algorithm is not supported for the PKCS#8 format.

Because the obsolete pbeWithMD5AndDES-CBC algorithm does not authenticate the ciphertext, it is vulnerable to padding oracle attacks that can let an attacker recover the plaintext.

Secret

This field contains sensitive information. Use a secret reference rather than a literal value.

Type: string
Default: ""

sasl

Specify one or more methods of SASL authentication. SASL is tried in order; if the broker supports the first mechanism, all connections will use that mechanism. If the first mechanism fails, the client will pick the first supported mechanism. If the broker does not support any client mechanisms, connections will fail.

Type: array of object

sasl[].mechanism

The SASL mechanism to use.

Type: string

Option	Summary
AWS_MSK_IAM	AWS IAM based authentication as specified by the 'aws-msk-iam-auth' java library.
OAUTHBEARER	OAuth Bearer based authentication.
PLAIN	Plain text authentication.
REDPANDA_CLOUD_SERVICE_ACCOUNT	Redpanda Cloud Service Account authentication when running in Redpanda Cloud.
SCRAM-SHA-256	SCRAM based authentication as specified in RFC5802.
SCRAM-SHA-512	SCRAM based authentication as specified in RFC5802.
none	Disable sasl authentication

sasl[].username

A username to provide for PLAIN or SCRAM-* authentication.

Type: string
Default: ""

sasl[].password

A password to provide for PLAIN or SCRAM-* authentication.

Secret

This field contains sensitive information. Use a secret reference rather than a literal value.

Type: string
Default: ""

sasl[].token

The token to use for a single session's OAUTHBEARER authentication.

Secret

This field contains sensitive information. Use a secret reference rather than a literal value.

Type: string
Default: ""

sasl[].extensions

Key/value pairs to add to OAUTHBEARER authentication requests.

Type: map of string

sasl[].aws

Contains AWS specific fields for when the mechanism is set to AWS_MSK_IAM.

Type: object

sasl[].aws.region

The AWS region to target.

Type: string

sasl[].aws.endpoint

Allows you to specify a custom endpoint for the AWS API.

Type: string

sasl[].aws.tcp

TCP socket configuration.

Type: object

sasl[].aws.tcp.connect_timeout

Maximum amount of time a dial will wait for a connect to complete. Zero disables.

Type: string
Default: "0s"

sasl[].aws.tcp.keep_alive

TCP keep-alive probe configuration.

Type: object

sasl[].aws.tcp.keep_alive.idle

Duration the connection must be idle before sending the first keep-alive probe. Zero defaults to 15s. Negative values disable keep-alive probes.

Type: string
Default: "15s"

sasl[].aws.tcp.keep_alive.interval

Duration between keep-alive probes. Zero defaults to 15s.

Type: string
Default: "15s"

sasl[].aws.tcp.keep_alive.count

Maximum unanswered keep-alive probes before dropping the connection. Zero defaults to 9.

Type: int
Default: 9

sasl[].aws.tcp.tcp_user_timeout

Maximum time to wait for acknowledgment of transmitted data before killing the connection. Linux-only (kernel 2.6.37+), ignored on other platforms. When enabled, keep_alive.idle must be greater than this value per RFC 5482. Zero disables.

Type: string
Default: "0s"

sasl[].aws.credentials

Optional manual configuration of AWS credentials to use. More information can be found in this document.

Type: object

sasl[].aws.credentials.profile

A profile from ~/.aws/credentials to use.

Type: string

sasl[].aws.credentials.id

The ID of credentials to use.

Type: string

sasl[].aws.credentials.secret

The secret for the credentials being used.

Secret

This field contains sensitive information. Use a secret reference rather than a literal value.

Type: string

sasl[].aws.credentials.token

The token for the credentials being used, required when using short term credentials.

Secret

This field contains sensitive information. Use a secret reference rather than a literal value.

Type: string

sasl[].aws.credentials.from_ec2_role

Use the credentials of a host EC2 machine configured to assume an IAM role associated with the instance.

Type: bool

sasl[].aws.credentials.role

A role ARN to assume.

Type: string

sasl[].aws.credentials.role_external_id

An external ID to provide when assuming a role.

Type: string

metadata_max_age

The maximum age of metadata before it is refreshed. This interval also controls how frequently regex topic patterns are re-evaluated to discover new matching topics.

Type: string
Default: "1m"

request_timeout_overhead

The request time overhead. Uses the given time as overhead while deadlining requests. Roughly equivalent to request.timeout.ms, but grants additional time to requests that have timeout fields.

Type: string
Default: "10s"

conn_idle_timeout

The rough amount of time to allow connections to idle before they are closed.

Type: string
Default: "20s"

tcp

TCP socket configuration.

Type: object

tcp.connect_timeout

Maximum amount of time a dial will wait for a connect to complete. Zero disables.

Type: string
Default: "0s"

tcp.keep_alive

TCP keep-alive probe configuration.

Type: object

tcp.keep_alive.idle

Duration the connection must be idle before sending the first keep-alive probe. Zero defaults to 15s. Negative values disable keep-alive probes.

Type: string
Default: "15s"

tcp.keep_alive.interval

Duration between keep-alive probes. Zero defaults to 15s.

Type: string
Default: "15s"

tcp.keep_alive.count

Maximum unanswered keep-alive probes before dropping the connection. Zero defaults to 9.

Type: int
Default: 9

tcp.tcp_user_timeout

Maximum time to wait for acknowledgment of transmitted data before killing the connection. Linux-only (kernel 2.6.37+), ignored on other platforms. When enabled, keep_alive.idle must be greater than this value per RFC 5482. Zero disables.

Type: string
Default: "0s"

topic

A topic to write messages to.

This field supports interpolation functions.

Type: string

key

An optional key to populate for each message.

This field supports interpolation functions.

Type: string

partition

An optional explicit partition to set for each message. This field is only relevant when the partitioner is set to manual. The provided interpolation string must be a valid integer.

This field supports interpolation functions.

Type: string

metadata

Determine which (if any) metadata values should be added to messages as headers.

Type: object

metadata.include_prefixes

Provide a list of explicit metadata key prefixes to match against.

Type: array of string
Default: []

metadata.include_patterns

Provide a list of explicit metadata key regular expression (re2) patterns to match against.

Type: array of string
Default: []

timestamp_ms

An optional timestamp to set for each message expressed in milliseconds. When left empty, the current timestamp is used.

This field supports interpolation functions.

Type: string

max_in_flight

The maximum number of batches to be sending in parallel at any given time.

Type: int
Default: 256

batching

Optional explicit batching policy for the output. Note that when batches are formed at the input level they can be expanded by this policy, but not contracted. When consuming data from a Redpanda input it is recommended to tune batches from the input config via the max_yield_batch_bytes field, or the unordered_processing.batching field if appropriate.

Type: object

batching.count

A number of messages at which the batch should be flushed. If 0 disables count based batching.

Type: int
Default: 0

batching.byte_size

An amount of bytes at which the batch should be flushed. If 0 disables size based batching.

Type: int
Default: 0

batching.period

A period in which an incomplete batch should be flushed regardless of its size.

Type: string
Default: ""

batching.check

A Bloblang query that should return a boolean value indicating whether a message should end a batch.

Type: string
Default: ""

batching.processors

A list of processors to apply to a batch as it is flushed. This allows you to aggregate and archive the batch however you see fit. Please note that all resulting messages are flushed as a single batch, therefore splitting the batch into smaller batches using these processors is a no-op.

Type: array of processor

inject_tracing_map

EXPERIMENTAL: A Bloblang mapping used to inject an object containing tracing propagation information into outbound messages. The specification of the injected fields will match the format used by the service wide tracer.

Type: string

partitioner

Override the default murmur2 hashing partitioner.

Type: string

Option	Summary
least_backup	Chooses the least backed up partition (the partition with the fewest amount of buffered records). Partitions are selected per batch.
manual	Manually select a partition for each message, requires the field partition to be specified.
murmur2_hash	Kafka's default hash algorithm that uses a 32-bit murmur2 hash of the key to compute which partition the record will be on.
round_robin	Round-robin's messages through all available partitions. This algorithm has lower throughput and causes higher CPU load on brokers, but can be useful if you want to ensure an even distribution of records to partitions.

idempotent_write

Enable the idempotent write producer option. When enabled, the producer initializes a producer ID and uses it to guarantee exactly-once semantics per partition (no duplicates on retries). This requires the IDEMPOTENT_WRITE permission on the CLUSTER resource. If your cluster does not grant this permission or uses ACLs restrictively, disable this option. Note: Idempotent writes are strictly a win for data integrity but may be unavailable in restricted environments (e.g., some managed Kafka services, Redpanda with strict ACLs). Disabling this option is safe and only affects retry behavior—duplicates may occur on producer retries, but the pipeline will continue to function normally.

Type: bool
Default: true

acks

The number of acknowledgements the leader broker must receive from ISR brokers before responding to the produce request. When idempotent_write is enabled this must be set to all.

Type: string
Default: "all"

Option	Summary
all	Wait for all in-sync replicas to acknowledge (acks=-1). Required when idempotent_write is enabled.
leader	Wait for the leader broker to acknowledge (acks=1). Messages are lost if the leader fails before replication.
none	Do not wait for any acknowledgement (acks=0). Highest throughput but messages may be lost.

compression

Optionally set an explicit compression type. The default preference is to use snappy when the broker supports it, and fall back to none if not.

Type: string

Options: lz4, snappy, gzip, none, zstd

allow_auto_topic_creation

Enables topics to be auto created if they do not exist when fetching their metadata.

Type: bool
Default: true

timeout

The maximum period of time to wait for message sends before abandoning the request and retrying

Type: string
Default: "10s"

max_message_bytes

The maximum size of a produced record batch in bytes. A MESSAGE_TOO_LARGE error is returned if a batch exceeds this limit. This field maps to the max.message.bytes Kafka property. Ensure the Redpanda broker's kafka_batch_max_bytes property is at least as large as this value, see https://docs.redpanda.com/current/reference/properties/cluster-properties/#kafka_batch_max_bytes.

Type: string
Default: "1MiB"

broker_write_max_bytes

The upper bound for the number of bytes written to a broker connection in a single write. This field corresponds to Kafka's socket.request.max.bytes.

Type: string
Default: "100MiB"

max_buffered_records

The maximum number of records the client will buffer in memory before blocking. When this limit is reached, Produce() calls will block until buffered records are delivered and space frees up. Increase this value for high-throughput pipelines to avoid back-pressure stalls.

Type: int
Default: 10000

max_buffered_bytes

The maximum number of bytes the client will buffer in memory before blocking. When this limit is reached, Produce() calls will block until buffered records are delivered. Set to 0 to disable the byte-level limit (only max_buffered_records applies). This limit is checked after max_buffered_records.

Type: string
Default: "0"

max_in_flight_requests

The maximum number of produce requests in flight per broker connection. While idempotent_write is enabled (the default) this must be 1, as the client relies on a single in-flight request per broker to guarantee ordering. To use higher values you must set idempotent_write to false, which allows requests to be pipelined for throughput but may cause duplicate and out-of-order delivery on retries. Note that this is distinct from the output's max_in_flight field, which counts message batches being written in parallel rather than produce requests on the wire. A value of 1 is not a throughput ceiling: records from concurrent writes are coalesced into fewer, larger produce requests.

Type: int
Default: 1

record_retries

The maximum number of times a record produce is retried on failure before the record is failed. When a record fails, all records buffered in the same partition are also failed to preserve gapless ordering. Set to 0 for unlimited retries (the default). With idempotent_write enabled, retries are only enforced when safe to do so without creating invalid sequence numbers.

Type: int
Default: 0

record_delivery_timeout

The maximum time a record can sit in the producer buffer before it is failed, roughly equivalent to Kafka's delivery.timeout.ms. This is evaluated before writing a request or after a produce response. When a record times out, all records in the same partition are also failed. Set to 0s for no timeout (the default). With idempotent_write enabled, timeouts are only enforced when safe to do so without creating invalid sequence numbers.

Type: string
Default: "0s"